# system

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The compiler depends on the System module to work properly and the System module depends on the compiler. Most of the routines listed here use special compiler magic.

Each module implicitly imports the System module; it must not be listed explicitly. Because of this there cannot be a user-defined module named `system`.

# System module

The System module imports several separate modules, and their documentation is in separate files:

- iterators
- exceptions
- assertions
- dollars
- ctypes
- repr_v2

Here is a short overview of the most commonly used functions from the `system` module. Function names in the tables below are clickable and will take you to the full documentation of the function.

There are many more functions available than the ones listed in this overview. Use the table of contents on the left-hand side and/or `Ctrl+F` to navigate through this module.

## Strings and characters

Proc | Usage
--- | ---
len(s) | Return the length of a string
chr(i) | Convert an `int` in the range `0..255` to a character
ord(c) | Return `int` value of a character
a & b | Concatenate two strings
s.add(c) | Add character to the string
$ | Convert various types to string

See also:

- strutils module for common string functions
- strformat module for string interpolation and formatting
- unicode module for Unicode UTF-8 handling
- strscans for `scanf` and `scanp` macros, which offer easier substring extraction than regular expressions
- strtabs module for efficient hash tables (dictionaries, in some programming languages) mapping from strings to strings

## Seqs

Proc | Usage
--- | ---
newSeq | Create a new sequence of a given length
newSeqOfCap | Create a new sequence with zero length and a given capacity
setLen | Set the length of a sequence
len | Return the length of a sequence
@ | Turn an array into a sequence
add | Add an item to the sequence
insert | Insert an item at a specific position
delete | Delete an item while preserving the order of elements (`O(n)` operation)
del | `O(1)` removal, doesn't preserve the order
pop | Remove and return last item of a sequence
x & y | Concatenate two sequences
x[a .. b] | Slice of a sequence (both ends included)
x[a .. ^b] | Slice of a sequence but `b` is a reversed index (both ends included)
x[a ..< b] | Slice of a sequence (excluded upper bound)

See also:

- sequtils module for operations on container types (including strings)
- json module for a structure which allows heterogeneous members
- lists module for linked lists

## Sets

Built-in bit sets.

Proc | Usage
--- | ---
incl | Include element `y` in the set `x`
excl | Exclude element `y` from the set `x`
card | Return the cardinality of the set, i.e. the number of elements
a * b | Intersection
a + b | Union
a - b | Difference
contains | Check if an element is in the set
a < b | Check if `a` is a subset of `b`

See also:

- setutils module for bit set convenience functions
- sets module for hash sets
- intsets module for efficient int sets

## Numbers

Proc | Usage | Also known as (in other languages)
--- | --- | ---
div | Integer division | `//`
mod | Integer modulo (remainder) | `%`
shl | Shift left | `<<`
shr | Shift right | `>>`
ashr | Arithmetic shift right |
and | Bitwise `and` | `&`
or | Bitwise `or` | `|`
xor | Bitwise `xor` | `^`
not | Bitwise `not` (complement) | `~`
toInt | Convert floating-point number into an `int` |
toFloat | Convert an integer into a `float` |

See also:

- math module for mathematical operations like trigonometric functions, logarithms, square and cubic roots, etc.
- complex module for operations on complex numbers
- rationals module for rational numbers

## Ordinals

Ordinal type includes integer, bool, character, and enumeration types, as well as their subtypes.

Proc | Usage
--- | ---
succ | Successor of the value
pred | Predecessor of the value
inc | Increment the ordinal
dec | Decrement the ordinal
high | Return the highest possible value
low | Return the lowest possible value
ord | Return `int` value of an ordinal value

## Misc

Proc | Usage
--- | ---
is | Check if two arguments are of the same type
isnot | Negated version of `is`
!= | Not equals
addr | Take the address of a memory location
T and F | Boolean `and`
T or F | Boolean `or`
T xor F | Boolean `xor` (exclusive or)
not T | Boolean `not`
a[^x] | Take the element at the reversed index `x`
a .. b | Binary slice that constructs an interval `[a, b]`
a ..^ b | Interval `[a, b]` but `b` as reversed index
a ..< b | Interval `[a, b)` (excluded upper bound)
runnableExamples | Create testable documentation

Default new string implementation used by Nim's core.Default seq implementation used by Nim's core.

Channel support for threads.

Note: This is part of the system module. Do not import it directly. To activate thread support compile with the `--threads:on` command line switch.

Note: Channels are designed for the `Thread` type. They are unstable when used with `spawn`

Note: The current implementation of message passing does not work with cyclic data structures.

Note: Channels cannot be passed between threads. Use globals or pass them by `ptr`.

# Example

The following is a simple example of two different ways to use channels: blocking and non-blocking.

    # Be sure to compile with --threads:on.
    # The channels and threads modules are part of system and should not be
    # imported.
    import std/os

    # Channels can either be:
    #  - declared at the module level, or
    #  - passed to procedures by ptr (raw pointer) -- see note on safety.
    #
    # For simplicity, in this example a channel is declared at module scope.
    # Channels are generic, and they include support for passing objects between
    # threads.
    # Note that objects passed through channels will be deeply copied.
    var chan: Channel[string]

    # This proc will be run in another thread using the threads module.
    proc firstWorker() =
      chan.send("Hello World!")

    # This is another proc to run in a background thread. This proc takes a while
    # to send the message since it sleeps for 2 seconds (or 2000 milliseconds).
    proc secondWorker() =
      sleep(2000)
      chan.send("Another message")

    # Initialize the channel.
    chan.open()

    # Launch the worker.
    var worker1: Thread[void]
    createThread(worker1, firstWorker)

    # Block until the message arrives, then print it out.
    echo chan.recv() # "Hello World!"

    # Wait for the thread to exit before moving on to the next example.
    worker1.joinThread()

    # Launch the other worker.
    var worker2: Thread[void]
    createThread(worker2, secondWorker)
    # This time, use a non-blocking approach with tryRecv.
    # Since the main thread is not blocked, it could be used to perform other
    # useful work while it waits for data to arrive on the channel.
    while true:
      let tried = chan.tryRecv()
      if tried.dataAvailable:
        echo tried.msg # "Another message"
        break

      echo "Pretend I'm doing useful work..."
      # For this example, sleep in order not to flood stdout with the above
      # message.
      sleep(400)

    # Wait for the second thread to exit before cleaning up the channel.
    worker2.joinThread()

    # Clean up the channel.
    chan.close()

## Sample output

The program should output something similar to this, but keep in mind that exact results may vary in the real world:

    Hello World!
    Pretend I'm doing useful work...
    Pretend I'm doing useful work...
    Pretend I'm doing useful work...
    Pretend I'm doing useful work...
    Pretend I'm doing useful work...
    Another message

## Passing Channels Safely

Note that when passing objects to procedures on another thread by pointer (for example through a thread's argument), objects created using the default allocator will use thread-local, GC-managed memory. Thus it is generally safer to store channel objects in global variables (as in the above example), in which case they will use a process-wide (thread-safe) shared heap.

However, it is possible to manually allocate shared memory for channels using e.g. `system.allocShared0` and pass these pointers through thread arguments:

    proc worker(channel: ptr Channel[string]) =
      let greeting = channel[].recv()
      echo greeting

    proc localChannelExample() =
      # Use allocShared0 to allocate some shared-heap memory and zero it.
      # The usual warnings about dealing with raw pointers apply. Exercise caution.
      var channel = cast[ptr Channel[string]](
        allocShared0(sizeof(Channel[string]))
      )
      channel[].open()
      # Create a thread which will receive the channel as an argument.
      var thread: Thread[ptr Channel[string]]
      createThread(thread, worker, channel)
      channel[].send("Hello from the main thread!")
      # Clean up resources.
      thread.joinThread()
      channel[].close()
      deallocShared(channel)

    localChannelExample() # "Hello from the main thread!"

# Imports

exceptions, since, ctypes, sysatomics, ansi_c, syslocks, threadtypes, miscdollars, stacktraces, assertions, iterators, coro_detection, dollars, typedthreads, countbits_impl, digitsutils, digitsutils, repr_v2, widestrs, syncio

# Types

    AllocStats = object

  Source Edit

    any {....deprecated: "Deprecated since v1.5; Use auto instead.".} = distinct auto

  Deprecated: Deprecated since v1.5; Use auto instead.
  Deprecated; Use `auto` instead. See https://github.com/nim-lang/RFCs/issues/281 Source Edit

    array[I; T] {.magic: "Array".}

  Generic type to construct fixed-length arrays. Source Edit

    auto {.magic: Expr.}

  Meta type for automatic type determination. Source Edit

    BackwardsIndex = distinct int

  Type that is constructed by `^` for reversed array accesses. (See ^ template) Source Edit

    bool {.magic: "Bool".} = enum
      false = 0, true = 1

  Built-in boolean type. Source Edit

    byte = uint8

  This is an alias for `uint8`, that is an unsigned integer, 8 bits wide. Source Edit

    CatchableError = object of Exception

  Abstract class for all exceptions that are catchable. Source Edit

    Channel[TMsg] {....gcsafe.} = RawChannel

  a channel for thread communication Source Edit

    char {.magic: Char.}

  Built-in 8 bit character type (unsigned). Source Edit

    csize {.importc: "size_t", nodecl, ...deprecated: "use `csize_t` instead".} = int

  Deprecated: use `csize_t` instead
  This isn't the same as `size_t` in C. Don't use it. Source Edit

    cstring {.magic: Cstring.}

  Built-in cstring (compatible string) type. Source Edit

    Defect = object of Exception

  Abstract base class for all exceptions that Nim's runtime raises but that are strictly uncatchable as they can also be mapped to a `quit` / `trap` / `exit` operation. Source Edit

    Endianness = enum
      littleEndian, bigEndian

  Type describing the endianness of a processor. Source Edit

    Exception {.compilerproc, magic: "Exception".} = object of RootObj
      parent*: ref Exception     ## Parent exception (can be used as a stack).
      name*: cstring             ## The exception's name is its Nim identifier.
                                 ## This field is filled automatically in the
                                 ## `raise` statement.
      msg* {.exportc: "message".}: string ## The exception's message. Not
                                          ## providing an exception message
                                          ## is bad style.
      when defined(js):
        trace*: string
      else:
        trace*: seq[StackTraceEntry]

  Base exception class.

  Each exception has to inherit from `Exception`. See the full exception hierarchy.

  Source Edit

    float {.magic: Float.}

  Default floating point type. Source Edit

    float32 {.magic: Float32.}

  32 bit floating point type. Source Edit

    float64 {.magic: Float.}

  64 bit floating point type. Source Edit

    ForeignCell = object
      data*: pointer

  Source Edit

    ForLoopStmt {.compilerproc.} = object

  A special type that marks a macro as a for-loop macro. See "For Loop Macro". Source Edit

    GC_Strategy = enum
      gcThroughput,             ## optimize for throughput
      gcResponsiveness,         ## optimize for responsiveness (default)
      gcOptimizeTime,           ## optimize for speed
      gcOptimizeSpace            ## optimize for memory footprint

  The strategy the GC should use for the application. Source Edit

    HSlice[T; U] = object
      a*: T                      ## The lower bound (inclusive).
      b*: U                      ## The upper bound (inclusive).

  "Heterogeneous" slice type. Source Edit

    int {.magic: Int.}

  Default integer type; bitwidth depends on architecture, but is always the same as a pointer. Source Edit

    int8 {.magic: Int8.}

  Signed 8 bit integer type. Source Edit

    int16 {.magic: Int16.}

  Signed 16 bit integer type. Source Edit

    int32 {.magic: Int32.}

  Signed 32 bit integer type. Source Edit

    int64 {.magic: Int64.}

  Signed 64 bit integer type. Source Edit

    iterable[T] {.magic: IterableType.}

  Represents an expression that yields `T` Source Edit

    JsRoot = ref object of RootObj

  Root type of the JavaScript object hierarchy Source Edit

    lent[T] {.magic: "BuiltinType".}

  Source Edit

    Natural = range[0 .. high(int)]

  is an `int` type ranging from zero to the maximum value of an `int`. This type is often useful for documentation and debugging. Source Edit

    NimNode {.magic: "PNimrodNode".} = ref NimNodeObj

  Represents a Nim AST node. Macros operate on this type. Source Edit

    NimSeqV2[T] = object

  Source Edit

    openArray[T] {.magic: "OpenArray".}

  Generic type to construct open arrays. Open arrays are implemented as a pointer to the array data and a length field. Source Edit

    Ordinal[T] {.magic: Ordinal.}

  Generic ordinal type. Includes integer, bool, character, and enumeration types as well as their subtypes. See also `SomeOrdinal`. Source Edit

    owned[T] {.magic: "BuiltinType".}

  type constructor to mark a ref/ptr or a closure as `owned`. Source Edit

    PFrame = ptr TFrame

  Represents a runtime frame of the call stack; part of the debugger API. Source Edit

    pointer {.magic: Pointer.}

  Built-in pointer type, use the `addr` operator to get a pointer to a variable. Source Edit

    Positive = range[1 .. high(int)]

  is an `int` type ranging from one to the maximum value of an `int`. This type is often useful for documentation and debugging. Source Edit

    ptr[T] {.magic: Pointer.}

  Built-in generic untraced pointer type. Source Edit

    range[T] {.magic: "Range".}

  Generic type to construct range types. Source Edit

    ref[T] {.magic: Pointer.}

  Built-in generic traced pointer type. Source Edit

    RootEffect {.compilerproc.} = object of RootObj

  Base effect class.

  Each effect should inherit from `RootEffect` unless you know what you're doing.

  Source Edit

    RootObj {.compilerproc, inheritable.} = object

  The root of Nim's object hierarchy.

  Objects should inherit from `RootObj` or one of its descendants. However, objects that have no ancestor are also allowed.

  Source Edit

    RootRef = ref RootObj

  Reference to `RootObj`. Source Edit

    seq[T] {.magic: "Seq".}

  Generic type to construct sequences. Source Edit

    set[T] {.magic: "Set".}

  Generic type to construct bit sets. Source Edit

    sink[T] {.magic: "BuiltinType".}

  Source Edit

    Slice[T] = HSlice[T, T]

  An alias for `HSlice[T, T]`. Source Edit

    SomeFloat = float | float32 | float64

  Type class matching all floating point number types. Source Edit

    SomeInteger = SomeSignedInt | SomeUnsignedInt

  Type class matching all integer types. Source Edit

    SomeNumber = SomeInteger | SomeFloat

  Type class matching all number types. Source Edit

    SomeOrdinal = int | int8 | int16 | int32 | int64 | bool | enum | uint | uint8 |
        uint16 |
        uint32 |
        uint64

  Type class matching all ordinal types; however this includes enums with holes. See also `Ordinal` Source Edit

    SomeSignedInt = int | int8 | int16 | int32 | int64

  Type class matching all signed integer types. Source Edit

    SomeUnsignedInt = uint | uint8 | uint16 | uint32 | uint64

  Type class matching all unsigned integer types. Source Edit

    StackTraceEntry = object
      procname*: cstring         ## Name of the proc that is currently executing.
      line*: int                 ## Line number of the proc that is currently executing.
      filename*: cstring         ## Filename of the proc that is currently executing.
      when NimStackTraceMsgs:
        frameMsg*: string ## When a stacktrace is generated in a given frame and
                          ## rendered at a later time, we should ensure the stacktrace
                          ## data isn't invalidated; any pointer into PFrame is
                          ## subject to being invalidated so shouldn't be stored.
      when defined(nimStackTraceOverride):
        programCounter*: uint ## Program counter - will be used to get the rest of the info,
                              ## when `$` is called on this type. We can't use
                              ## "cuintptr_t" in here.
        procnameStr*, filenameStr*: string ## GC-ed alternatives to "procname" and "filename"

  In debug mode exceptions store the stack trace that led to them. A `StackTraceEntry` is a single entry of the stack trace. Source Edit

    static[T] {.magic: "Static".}

  Meta type representing all values that can be evaluated at compile-time.

  The type coercion `static(x)` can be used to force the compile-time evaluation of the given expression `x`.

  Source Edit

    string {.magic: String.}

  Built-in string type. Source Edit

    TaintedString {....deprecated: "Deprecated since 1.5".} = string

  Deprecated: Deprecated since 1.5
  Source Edit

    TFrame {.importc, nodecl, final.} = object
      prev*: PFrame              ## Previous frame; used for chaining the call stack.
      procname*: cstring         ## Name of the proc that is currently executing.
      line*: int                 ## Line number of the proc that is currently executing.
      filename*: cstring         ## Filename of the proc that is currently executing.
      len*: int16                ## Length of the inspectable slots.
      calldepth*: int16          ## Used for max call depth checking.
      when NimStackTraceMsgs:
        frameMsgLen*: int        ## end position in frameMsgBuf for this frame.

  The frame itself. Source Edit

    type[T] {.magic: "Type".}

  Meta type representing the type of all type values.

  The coercion `type(x)` can be used to obtain the type of the given expression `x`.

  Source Edit

    typed {.magic: Stmt.}

  Meta type to denote an expression that is resolved (for templates). Source Edit

    typedesc {.magic: TypeDesc.}

  Meta type to denote a type description. Source Edit

    TypeOfMode = enum
      typeOfProc,               ## Prefer the interpretation that means `x` is a proc call.
      typeOfIter                 ## Prefer the interpretation that means `x` is an iterator call.

  Possible modes of `typeof`. Source Edit

    uint {.magic: UInt.}

  Unsigned default integer type. Source Edit

    uint8 {.magic: UInt8.}

  Unsigned 8 bit integer type. Source Edit

    uint16 {.magic: UInt16.}

  Unsigned 16 bit integer type. Source Edit

    uint32 {.magic: UInt32.}

  Unsigned 32 bit integer type. Source Edit

    uint64 {.magic: UInt64.}

  Unsigned 64 bit integer type. Source Edit

    UncheckedArray[T] {.magic: "UncheckedArray".}

  Source Edit

    untyped {.magic: Expr.}

  Meta type to denote an expression that is not resolved (for templates). Source Edit

    varargs[T] {.magic: "Varargs".}

  Generic type to construct a varargs type. Source Edit

    void {.magic: "VoidType".}

  Meta type to denote the absence of any type. Source Edit

# Vars

    errorMessageWriter: (proc (msg: string) {....tags: [WriteIOEffect], gcsafe,
        nimcall, ...raises: [].})

  Function that will be called instead of `stdmsg.write` when printing stacktrace. Unstable API. Source Edit

    globalRaiseHook: proc (e: ref Exception): bool {.nimcall, ...gcsafe.}

  With this hook you can influence exception handling on a global level. If not nil, every 'raise' statement ends up calling this hook.
  Warning: Ordinary application code should never set this hook! You better know what you do when setting this.

  If `globalRaiseHook` returns false, the exception is caught and does not propagate further through the call stack.

  Source Edit

    localRaiseHook {.threadvar.}: proc (e: ref Exception): bool {.nimcall, ...gcsafe.}

  With this hook you can influence exception handling on a thread local level. If not nil, every 'raise' statement ends up calling this hook.
  Warning: Ordinary application code should never set this hook! You better know what you do when setting this.

  If `localRaiseHook` returns false, the exception is caught and does not propagate further through the call stack.

  Source Edit

    nimThreadDestructionHandlers {.threadvar.}: seq[
        proc () {.closure, ...gcsafe, raises: [].}]

  Source Edit

    onUnhandledException: (proc (errorMsg: string) {.nimcall, ...gcsafe.})

  Set this error handler to override the existing behaviour on an unhandled exception.

  The default is to write a stacktrace to `stderr` and then call `quit(1)`. Unstable API.

  Source Edit

    outOfMemHook: proc () {.nimcall, ...tags: [], gcsafe, raises: [].}

  Set this variable to provide a procedure that should be called in case of an out of memory event. The standard handler writes an error message and terminates the program.

  `outOfMemHook` can be used to raise an exception in case of OOM like so:

      var gOutOfMem: ref EOutOfMemory
      new(gOutOfMem) # need to be allocated *before* OOM really happened!
      gOutOfMem.msg = "out of memory"

      proc handleOOM() =
        raise gOutOfMem

      system.outOfMemHook = handleOOM

  If the handler does not raise an exception, ordinary control flow continues and the program is terminated.

  Source Edit

    programResult {.compilerproc, exportc: "nim_program_result".}: int

  deprecated, prefer `quit` or `exitprocs.getProgramResult`, `exitprocs.setProgramResult`. Source Edit

    unhandledExceptionHook: proc (e: ref Exception) {.nimcall, ...tags: [], gcsafe,
        raises: [].}

  Set this variable to provide a procedure that should be called in case of an `unhandle exception` event. The standard handler writes an error message and terminates the program, except when using `--os:any` Source Edit

# Lets

    nimvm {.magic: "Nimvm", compileTime.}: bool = false

  May be used only in `when` expression. It is true in Nim VM context and false otherwise. Source Edit

# Consts

    appType {.magic: "AppType".}: string = ""

  A string that describes the application type. Possible values: `"console"`, `"gui"`, `"lib"`. Source Edit

    CompileDate {.magic: "CompileDate".}: string = "0000-00-00"

  The date (in UTC) of compilation as a string of the form `YYYY-MM-DD`. This works thanks to compiler magic. Source Edit

    CompileTime {.magic: "CompileTime".}: string = "00:00:00"

  The time (in UTC) of compilation as a string of the form `HH:MM:SS`. This works thanks to compiler magic. Source Edit

    cpuEndian {.magic: "CpuEndian".}: Endianness = littleEndian

  The endianness of the target CPU. This is a valuable piece of information for low-level code only. This works thanks to compiler magic. Source Edit

    hostCPU {.magic: "HostCPU".}: string = ""

  A string that describes the host CPU.

  Possible values: `"i386"`, `"alpha"`, `"powerpc"`, `"powerpc64"`, `"powerpc64el"`, `"sparc"`, `"amd64"`, `"mips"`, `"mipsel"`, `"arm"`, `"arm64"`, `"mips64"`, `"mips64el"`, `"riscv32"`, `"riscv64"`, `"loongarch64"`, `"s390x"`.

  Source Edit

    hostOS {.magic: "HostOS".}: string = ""

  A string that describes the host operating system.

  Possible values: `"windows"`, `"macosx"`, `"linux"`, `"netbsd"`, `"freebsd"`, `"openbsd"`, `"solaris"`, `"aix"`, `"haiku"`, `"standalone"`.

  Source Edit

    Inf = 0x7FF0000000000000'f64

  Contains the IEEE floating point value of positive infinity. Source Edit

    isMainModule {.magic: "IsMainModule".}: bool = false

  True only when accessed in the main module. This works thanks to compiler magic. It is useful to embed testing code in a module. Source Edit

    NaN = 0x7FFFFFFFFFFFFFFF'f64

  Contains an IEEE floating point value of Not A Number.

  Note that you cannot compare a floating point value to this value and expect a reasonable result - use the `isNaN` or `classify` procedure in the math module for checking for NaN.

  Source Edit

    NegInf = 0xFFF0000000000000'f64

  Contains the IEEE floating point value of negative infinity. Source Edit

    NimMajor {.intdefine.}: int = 2

  is the major number of Nim's version. Example:

      when (NimMajor, NimMinor, NimPatch) >= (1, 3, 1): discard

  Source Edit

    NimMinor {.intdefine.}: int = 2

  is the minor number of Nim's version. Odd for devel, even for releases. Source Edit

    NimPatch {.intdefine.}: int = 8

  is the patch number of Nim's version. Odd for devel, even for releases. Source Edit

    NimVersion: string = "2.2.8"

  is the version of Nim as a string. Source Edit

    off = false

  Alias for `false`. Source Edit

    on = true

  Alias for `true`. Source Edit

    QuitFailure = 1

  is the value that should be passed to quit to indicate failure. Source Edit

    QuitSuccess = 0

  is the value that should be passed to quit to indicate success. Source Edit

# Procs

    proc `%%`(x, y: int): int {.inline, ...raises: [], tags: [], forbids: [].}

  Treats `x` and `y` as unsigned and compute the modulo of `x` and `y`.

  The result is truncated to fit into the result. This implements modulo arithmetic. No overflow errors are possible.

  Source Edit

    proc `%%`(x, y: int8): int8 {.inline, ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `%%`(x, y: int16): int16 {.inline, ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `%%`(x, y: int32): int32 {.inline, ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `%%`(x, y: int64): int64 {.inline, ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `&`(x, y: char): string {.magic: "ConStrStr", noSideEffect, ...raises: [],
                                   tags: [], forbids: [].}

  Concatenates characters `x` and `y` into a string.

      assert('a' & 'b' == "ab")

  Source Edit

    proc `&`(x, y: string): string {.magic: "ConStrStr", noSideEffect, ...raises: [],
                                     tags: [], forbids: [].}

  Concatenates strings `x` and `y`.

      assert("ab" & "cd" == "abcd")

  Source Edit

    proc `&`(x: char; y: string): string {.magic: "ConStrStr", noSideEffect,
                                           ...raises: [], tags: [], forbids: [].}

  Concatenates `x` with `y`.

      assert('a' & "bc" == "abc")

  Source Edit

    proc `&`(x: string; y: char): string {.magic: "ConStrStr", noSideEffect,
                                           ...raises: [], tags: [], forbids: [].}

  Concatenates `x` with `y`.

      assert("ab" & 'c' == "abc")

  Source Edit

    proc `&`[T](x, y: sink seq[T]): seq[T] {.noSideEffect.}

  Concatenates two sequences.

  Requires copying of the sequences.

      assert(@[1, 2, 3, 4] & @[5, 6] == @[1, 2, 3, 4, 5, 6])

  See also:

  - add(var seq[T], openArray[T])
  Source Edit

    proc `&`[T](x: sink seq[T]; y: sink T): seq[T] {.noSideEffect.}

  Appends element y to the end of the sequence.

  Requires copying of the sequence.

      assert(@[1, 2, 3] & 4 == @[1, 2, 3, 4])

  See also:

  - add(var seq[T], T)
  Source Edit

    proc `&`[T](x: sink T; y: sink seq[T]): seq[T] {.noSideEffect.}

  Prepends the element x to the beginning of the sequence.

  Requires copying of the sequence.

      assert(1 & @[2, 3, 4] == @[1, 2, 3, 4])

  Source Edit

    proc `&=`(x: var string; y: string) {.magic: "AppendStrStr", noSideEffect,
                                          ...raises: [], tags: [], forbids: [].}

  Appends in place to a string.

      var a = "abc"
      a &= "de" # a <- "abcde"

  Source Edit

    proc `*`(x, y: float): float {.magic: "MulF64", noSideEffect, ...raises: [],
                                   tags: [], forbids: [].}

  Source Edit

    proc `*`(x, y: float32): float32 {.magic: "MulF64", noSideEffect, ...raises: [],
                                       tags: [], forbids: [].}

  Source Edit

    proc `*`(x, y: int): int {.magic: "MulI", noSideEffect, ...raises: [], tags: [],
                               forbids: [].}

  Binary `*` operator for an integer. Source Edit

    proc `*`(x, y: int8): int8 {.magic: "MulI", noSideEffect, ...raises: [], tags: [],
                                 forbids: [].}

  Source Edit

    proc `*`(x, y: int16): int16 {.magic: "MulI", noSideEffect, ...raises: [],
                                   tags: [], forbids: [].}

  Source Edit

    proc `*`(x, y: int32): int32 {.magic: "MulI", noSideEffect, ...raises: [],
                                   tags: [], forbids: [].}

  Source Edit

    proc `*`(x, y: int64): int64 {.magic: "MulI", noSideEffect, ...raises: [],
                                   tags: [], forbids: [].}

  Source Edit

    proc `*`(x, y: uint): uint {.magic: "MulU", noSideEffect, ...raises: [], tags: [],
                                 forbids: [].}

  Binary `*` operator for unsigned integers. Source Edit

    proc `*`(x, y: uint8): uint8 {.magic: "MulU", noSideEffect, ...raises: [],
                                   tags: [], forbids: [].}

  Source Edit

    proc `*`(x, y: uint16): uint16 {.magic: "MulU", noSideEffect, ...raises: [],
                                     tags: [], forbids: [].}

  Source Edit

    proc `*`(x, y: uint32): uint32 {.magic: "MulU", noSideEffect, ...raises: [],
                                     tags: [], forbids: [].}

  Source Edit

    proc `*`(x, y: uint64): uint64 {.magic: "MulU", noSideEffect, ...raises: [],
                                     tags: [], forbids: [].}

  Source Edit

    func `*`[T](x, y: set[T]): set[T] {.magic: "MulSet", ...raises: [], tags: [],
                                        forbids: [].}

  This operator computes the intersection of two sets.

  Example:

      assert {1, 2, 3} * {2, 3, 4} == {2, 3}

  Source Edit

    proc `*%`(x, y: int): int {.inline, ...raises: [], tags: [], forbids: [].}

  Treats `x` and `y` as unsigned and multiplies them.

  The result is truncated to fit into the result. This implements modulo arithmetic. No overflow errors are possible.

  Source Edit

    proc `*%`(x, y: int8): int8 {.inline, ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `*%`(x, y: int16): int16 {.inline, ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `*%`(x, y: int32): int32 {.inline, ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `*%`(x, y: int64): int64 {.inline, ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `*=`[T: float | float32 | float64](x: var T; y: T) {.inline, noSideEffect.}

  Multiplies in place a floating point number. Source Edit

    proc `*=`[T: SomeInteger](x: var T; y: T) {.inline, noSideEffect.}

  Binary `*=` operator for integers. Source Edit

    proc `+`(x, y: float): float {.magic: "AddF64", noSideEffect, ...raises: [],
                                   tags: [], forbids: [].}

  Source Edit

    proc `+`(x, y: float32): float32 {.magic: "AddF64", noSideEffect, ...raises: [],
                                       tags: [], forbids: [].}

  Source Edit

    proc `+`(x, y: int): int {.magic: "AddI", noSideEffect, ...raises: [], tags: [],
                               forbids: [].}

  Binary `+` operator for an integer. Source Edit

    proc `+`(x, y: int8): int8 {.magic: "AddI", noSideEffect, ...raises: [], tags: [],
                                 forbids: [].}

  Source Edit

    proc `+`(x, y: int16): int16 {.magic: "AddI", noSideEffect, ...raises: [],
                                   tags: [], forbids: [].}

  Source Edit

    proc `+`(x, y: int32): int32 {.magic: "AddI", noSideEffect, ...raises: [],
                                   tags: [], forbids: [].}

  Source Edit

    proc `+`(x, y: int64): int64 {.magic: "AddI", noSideEffect, ...raises: [],
                                   tags: [], forbids: [].}

  Source Edit

    proc `+`(x, y: uint): uint {.magic: "AddU", noSideEffect, ...raises: [], tags: [],
                                 forbids: [].}

  Binary `+` operator for unsigned integers. Source Edit

    proc `+`(x, y: uint8): uint8 {.magic: "AddU", noSideEffect, ...raises: [],
                                   tags: [], forbids: [].}

  Source Edit

    proc `+`(x, y: uint16): uint16 {.magic: "AddU", noSideEffect, ...raises: [],
                                     tags: [], forbids: [].}

  Source Edit

    proc `+`(x, y: uint32): uint32 {.magic: "AddU", noSideEffect, ...raises: [],
                                     tags: [], forbids: [].}

  Source Edit

    proc `+`(x, y: uint64): uint64 {.magic: "AddU", noSideEffect, ...raises: [],
                                     tags: [], forbids: [].}

  Source Edit

    proc `+`(x: float): float {.magic: "UnaryPlusF64", noSideEffect, ...raises: [],
                                tags: [], forbids: [].}

  Source Edit

    proc `+`(x: float32): float32 {.magic: "UnaryPlusF64", noSideEffect, ...raises: [],
                                    tags: [], forbids: [].}

  Source Edit

    proc `+`(x: int): int {.magic: "UnaryPlusI", noSideEffect, ...raises: [], tags: [],
                            forbids: [].}

  Unary `+` operator for an integer. Has no effect. Source Edit

    proc `+`(x: int8): int8 {.magic: "UnaryPlusI", noSideEffect, ...raises: [],
                              tags: [], forbids: [].}

  Source Edit

    proc `+`(x: int16): int16 {.magic: "UnaryPlusI", noSideEffect, ...raises: [],
                                tags: [], forbids: [].}

  Source Edit

    proc `+`(x: int32): int32 {.magic: "UnaryPlusI", noSideEffect, ...raises: [],
                                tags: [], forbids: [].}

  Source Edit

    proc `+`(x: int64): int64 {.magic: "UnaryPlusI", noSideEffect, ...raises: [],
                                tags: [], forbids: [].}

  Source Edit

    func `+`[T](x, y: set[T]): set[T] {.magic: "PlusSet", ...raises: [], tags: [],
                                        forbids: [].}

  This operator computes the union of two sets.

  Example:

      assert {1, 2, 3} + {2, 3, 4} == {1, 2, 3, 4}

  Source Edit

    proc `+%`(x, y: int): int {.inline, ...raises: [], tags: [], forbids: [].}

  Treats `x` and `y` as unsigned and adds them.

  The result is truncated to fit into the result. This implements modulo arithmetic. No overflow errors are possible.

  Source Edit

    proc `+%`(x, y: int8): int8 {.inline, ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `+%`(x, y: int16): int16 {.inline, ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `+%`(x, y: int32): int32 {.inline, ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `+%`(x, y: int64): int64 {.inline, ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `+=`[T: float | float32 | float64](x: var T; y: T) {.inline, noSideEffect.}

  Increments in place a floating point number. Source Edit

    proc `+=`[T: SomeInteger](x: var T; y: T) {.magic: "Inc", noSideEffect,
        ...raises: [], tags: [], forbids: [].}

  Increments an integer. Source Edit

    proc `-`(a, b: AllocStats): AllocStats {....raises: [], tags: [], forbids: [].}

  Source Edit

    proc `-`(x, y: float): float {.magic: "SubF64", noSideEffect, ...raises: [],
                                   tags: [], forbids: [].}

  Source Edit

    proc `-`(x, y: float32): float32 {.magic: "SubF64", noSideEffect, ...raises: [],
                                       tags: [], forbids: [].}

  Source Edit

    proc `-`(x, y: int): int {.magic: "SubI", noSideEffect, ...raises: [], tags: [],
                               forbids: [].}

  Binary `-` operator for an integer. Source Edit

    proc `-`(x, y: int8): int8 {.magic: "SubI", noSideEffect, ...raises: [], tags: [],
                                 forbids: [].}

  Source Edit

    proc `-`(x, y: int16): int16 {.magic: "SubI", noSideEffect, ...raises: [],
                                   tags: [], forbids: [].}

  Source Edit

    proc `-`(x, y: int32): int32 {.magic: "SubI", noSideEffect, ...raises: [],
                                   tags: [], forbids: [].}

  Source Edit

    proc `-`(x, y: int64): int64 {.magic: "SubI", noSideEffect, ...raises: [],
                                   tags: [], forbids: [].}

  Source Edit

    proc `-`(x, y: uint): uint {.magic: "SubU", noSideEffect, ...raises: [], tags: [],
                                 forbids: [].}

  Binary `-` operator for unsigned integers. Source Edit

    proc `-`(x, y: uint8): uint8 {.magic: "SubU", noSideEffect, ...raises: [],
                                   tags: [], forbids: [].}

  Source Edit

    proc `-`(x, y: uint16): uint16 {.magic: "SubU", noSideEffect, ...raises: [],
                                     tags: [], forbids: [].}

  Source Edit

    proc `-`(x, y: uint32): uint32 {.magic: "SubU", noSideEffect, ...raises: [],
                                     tags: [], forbids: [].}

  Source Edit

    proc `-`(x, y: uint64): uint64 {.magic: "SubU", noSideEffect, ...raises: [],
                                     tags: [], forbids: [].}

  Source Edit

    proc `-`(x: float): float {.magic: "UnaryMinusF64", noSideEffect, ...raises: [],
                                tags: [], forbids: [].}

  Source Edit

    proc `-`(x: float32): float32 {.magic: "UnaryMinusF64", noSideEffect,
                                    ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `-`(x: int): int {.magic: "UnaryMinusI", noSideEffect, ...raises: [],
                            tags: [], forbids: [].}

  Unary `-` operator for an integer. Negates `x`. Source Edit

    proc `-`(x: int8): int8 {.magic: "UnaryMinusI", noSideEffect, ...raises: [],
                              tags: [], forbids: [].}

  Source Edit

    proc `-`(x: int16): int16 {.magic: "UnaryMinusI", noSideEffect, ...raises: [],
                                tags: [], forbids: [].}

  Source Edit

    proc `-`(x: int32): int32 {.magic: "UnaryMinusI", noSideEffect, ...raises: [],
                                tags: [], forbids: [].}

  Source Edit

    proc `-`(x: int64): int64 {.magic: "UnaryMinusI64", noSideEffect, ...raises: [],
                                tags: [], forbids: [].}

  Source Edit

    func `-`[T](x, y: set[T]): set[T] {.magic: "MinusSet", ...raises: [], tags: [],
                                        forbids: [].}

  This operator computes the difference of two sets.

  Example:

      assert {1, 2, 3} - {2, 3, 4} == {1}

  Source Edit

    proc `-%`(x, y: int): int {.inline, ...raises: [], tags: [], forbids: [].}

  Treats `x` and `y` as unsigned and subtracts them.

  The result is truncated to fit into the result. This implements modulo arithmetic. No overflow errors are possible.

  Source Edit

    proc `-%`(x, y: int8): int8 {.inline, ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `-%`(x, y: int16): int16 {.inline, ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `-%`(x, y: int32): int32 {.inline, ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `-%`(x, y: int64): int64 {.inline, ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `-=`[T: float | float32 | float64](x: var T; y: T) {.inline, noSideEffect.}

  Decrements in place a floating point number. Source Edit

    proc `-=`[T: SomeInteger](x: var T; y: T) {.magic: "Dec", noSideEffect,
        ...raises: [], tags: [], forbids: [].}

  Decrements an integer. Source Edit

    proc `..`[T, U](a: sink T; b: sink U): HSlice[T, U] {.noSideEffect, inline,
        magic: "DotDot", ...raises: [], tags: [], forbids: [].}

  Binary slice operator that constructs an interval `[a, b]`, both `a` and `b` are inclusive.

  Slices can also be used in the set constructor and in ordinal case statements, but then they are special-cased by the compiler.

      let a = [10, 20, 30, 40, 50]
      echo a[2 .. 3] # @[30, 40]

  Source Edit

    proc `..`[T](b: sink T): HSlice[int, T] {.noSideEffect, inline, magic: "DotDot",
        ...deprecated: "replace `..b` with `0..b`", raises: [], tags: [], forbids: [].}

  Deprecated: replace `..b` with `0..b`

  Unary slice operator that constructs an interval `[default(int), b]`.

      let a = [10, 20, 30, 40, 50]
      echo a[.. 2] # @[10, 20, 30]

  Source Edit

    proc `/`(x, y: float): float {.magic: "DivF64", noSideEffect, ...raises: [],
                                   tags: [], forbids: [].}

  Source Edit

    proc `/`(x, y: float32): float32 {.magic: "DivF64", noSideEffect, ...raises: [],
                                       tags: [], forbids: [].}

  Source Edit

    proc `/`(x, y: int): float {.inline, noSideEffect, ...raises: [], tags: [],
                                 forbids: [].}

  Division of integers that results in a float.

      echo 7 / 5 # => 1.4

  See also:

  - div
  - mod
  Source Edit

    proc `/%`(x, y: int): int {.inline, ...raises: [], tags: [], forbids: [].}

  Treats `x` and `y` as unsigned and divides them.

  The result is truncated to fit into the result. This implements modulo arithmetic. No overflow errors are possible.

  Source Edit

    proc `/%`(x, y: int8): int8 {.inline, ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `/%`(x, y: int16): int16 {.inline, ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `/%`(x, y: int32): int32 {.inline, ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `/%`(x, y: int64): int64 {.inline, ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `/=`(x: var float64; y: float64) {.inline, noSideEffect, ...raises: [],
                                            tags: [], forbids: [].}

  Divides in place a floating point number. Source Edit

    proc `/=`[T: float | float32](x: var T; y: T) {.inline, noSideEffect.}

  Divides in place a floating point number. Source Edit

    proc `<`(x, y: bool): bool {.magic: "LtB", noSideEffect, ...raises: [], tags: [],
                                 forbids: [].}

  Source Edit

    proc `<`(x, y: char): bool {.magic: "LtCh", noSideEffect, ...raises: [], tags: [],
                                 forbids: [].}

  Compares two chars and returns true if `x` is lexicographically before `y` (uppercase letters come before lowercase letters).

  Example:

      let
        a = 'a'
        b = 'b'
        c = 'Z'
      assert a < b
      assert not (a < a)
      assert not (a < c)

  Source Edit

    proc `<`(x, y: float): bool {.magic: "LtF64", noSideEffect, ...raises: [],
                                  tags: [], forbids: [].}

  Source Edit

    proc `<`(x, y: float32): bool {.magic: "LtF64", noSideEffect, ...raises: [],
                                    tags: [], forbids: [].}

  Source Edit

    proc `<`(x, y: int): bool {.magic: "LtI", noSideEffect, ...raises: [], tags: [],
                                forbids: [].}

  Returns true if `x` is less than `y`. Source Edit

    proc `<`(x, y: int8): bool {.magic: "LtI", noSideEffect, ...raises: [], tags: [],
                                 forbids: [].}

  Source Edit

    proc `<`(x, y: int16): bool {.magic: "LtI", noSideEffect, ...raises: [], tags: [],
                                  forbids: [].}

  Source Edit

    proc `<`(x, y: int32): bool {.magic: "LtI", noSideEffect, ...raises: [], tags: [],
                                  forbids: [].}

  Source Edit

    proc `<`(x, y: int64): bool {.magic: "LtI", noSideEffect, ...raises: [], tags: [],
                                  forbids: [].}

  Source Edit

    proc `<`(x, y: pointer): bool {.magic: "LtPtr", noSideEffect, ...raises: [],
                                    tags: [], forbids: [].}

  Source Edit

    proc `<`(x, y: string): bool {.magic: "LtStr", noSideEffect, ...raises: [],
                                   tags: [], forbids: [].}

  Compares two strings and returns true if `x` is lexicographically before `y` (uppercase letters come before lowercase letters).

  Example:

      let
        a = "abc"
        b = "abd"
        c = "ZZZ"
      assert a < b
      assert not (a < a)
      assert not (a < c)

  Source Edit

    proc `<`(x, y: uint): bool {.magic: "LtU", noSideEffect, ...raises: [], tags: [],
                                 forbids: [].}

  Returns true if `x < y`. Source Edit

    proc `<`(x, y: uint8): bool {.magic: "LtU", noSideEffect, ...raises: [], tags: [],
                                  forbids: [].}

  Source Edit

    proc `<`(x, y: uint16): bool {.magic: "LtU", noSideEffect, ...raises: [], tags: [],
                                   forbids: [].}

  Source Edit

    proc `<`(x, y: uint32): bool {.magic: "LtU", noSideEffect, ...raises: [], tags: [],
                                   forbids: [].}

  Source Edit

    proc `<`(x, y: uint64): bool {.magic: "LtU", noSideEffect, ...raises: [], tags: [],
                                   forbids: [].}

  Source Edit

    proc `<`[Enum: enum](x, y: Enum): bool {.magic: "LtEnum", noSideEffect,
        ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `<`[T: tuple](x, y: T): bool

  Generic lexicographic `<` operator for tuples that is lifted from the components of `x` and `y`. This implementation uses `cmp`. Source Edit

    proc `<`[T](x, y: ptr T): bool {.magic: "LtPtr", noSideEffect, ...raises: [],
                                     tags: [], forbids: [].}

  Source Edit

    proc `<`[T](x, y: ref T): bool {.magic: "LtPtr", noSideEffect, ...raises: [],
                                     tags: [], forbids: [].}

  Source Edit

    proc `<`[T](x, y: set[T]): bool {.magic: "LtSet", noSideEffect, ...raises: [],
                                      tags: [], forbids: [].}

  Returns true if `x` is a strict or proper subset of `y`.

  A strict or proper subset `x` has all of its members in `y` but `y` has more elements than `y`.

  Example:

      let
        a = {3, 5}
        b = {1, 3, 5, 7}
        c = {2}
      assert a < b
      assert not (a < a)
      assert not (a < c)

  Source Edit

    proc `<%`(x, y: int): bool {.inline, ...raises: [], tags: [], forbids: [].}

  Treats `x` and `y` as unsigned and compares them. Returns true if `unsigned(x) < unsigned(y)`. Source Edit

    proc `<%`(x, y: int8): bool {.inline, ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `<%`(x, y: int16): bool {.inline, ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `<%`(x, y: int32): bool {.inline, ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `<%`(x, y: int64): bool {.inline, ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `<=`(x, y: bool): bool {.magic: "LeB", noSideEffect, ...raises: [], tags: [],
                                  forbids: [].}

  Source Edit

    proc `<=`(x, y: char): bool {.magic: "LeCh", noSideEffect, ...raises: [], tags: [],
                                  forbids: [].}

  Compares two chars and returns true if `x` is lexicographically before `y` (uppercase letters come before lowercase letters).

  Example:

      let
        a = 'a'
        b = 'b'
        c = 'Z'
      assert a <= b
      assert a <= a
      assert not (a <= c)

  Source Edit

    proc `<=`(x, y: float): bool {.magic: "LeF64", noSideEffect, ...raises: [],
                                   tags: [], forbids: [].}

  Source Edit

    proc `<=`(x, y: float32): bool {.magic: "LeF64", noSideEffect, ...raises: [],
                                     tags: [], forbids: [].}

  Source Edit

    proc `<=`(x, y: int): bool {.magic: "LeI", noSideEffect, ...raises: [], tags: [],
                                 forbids: [].}

  Returns true if `x` is less than or equal to `y`. Source Edit

    proc `<=`(x, y: int8): bool {.magic: "LeI", noSideEffect, ...raises: [], tags: [],
                                  forbids: [].}

  Source Edit

    proc `<=`(x, y: int16): bool {.magic: "LeI", noSideEffect, ...raises: [], tags: [],
                                   forbids: [].}

  Source Edit

    proc `<=`(x, y: int32): bool {.magic: "LeI", noSideEffect, ...raises: [], tags: [],
                                   forbids: [].}

  Source Edit

    proc `<=`(x, y: int64): bool {.magic: "LeI", noSideEffect, ...raises: [], tags: [],
                                   forbids: [].}

  Source Edit

    proc `<=`(x, y: pointer): bool {.magic: "LePtr", noSideEffect, ...raises: [],
                                     tags: [], forbids: [].}

  Source Edit

    proc `<=`(x, y: string): bool {.magic: "LeStr", noSideEffect, ...raises: [],
                                    tags: [], forbids: [].}

  Compares two strings and returns true if `x` is lexicographically before `y` (uppercase letters come before lowercase letters).

  Example:

      let
        a = "abc"
        b = "abd"
        c = "ZZZ"
      assert a <= b
      assert a <= a
      assert not (a <= c)

  Source Edit

    proc `<=`(x, y: uint): bool {.magic: "LeU", noSideEffect, ...raises: [], tags: [],
                                  forbids: [].}

  Returns true if `x <= y`. Source Edit

    proc `<=`(x, y: uint8): bool {.magic: "LeU", noSideEffect, ...raises: [], tags: [],
                                   forbids: [].}

  Source Edit

    proc `<=`(x, y: uint16): bool {.magic: "LeU", noSideEffect, ...raises: [],
                                    tags: [], forbids: [].}

  Source Edit

    proc `<=`(x, y: uint32): bool {.magic: "LeU", noSideEffect, ...raises: [],
                                    tags: [], forbids: [].}

  Source Edit

    proc `<=`(x, y: uint64): bool {.magic: "LeU", noSideEffect, ...raises: [],
                                    tags: [], forbids: [].}

  Source Edit

    proc `<=`[Enum: enum](x, y: Enum): bool {.magic: "LeEnum", noSideEffect,
        ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `<=`[T: tuple](x, y: T): bool

  Generic lexicographic `<=` operator for tuples that is lifted from the components of `x` and `y`. This implementation uses `cmp`. Source Edit

    proc `<=`[T](x, y: ref T): bool {.magic: "LePtr", noSideEffect, ...raises: [],
                                      tags: [], forbids: [].}

  Source Edit

    proc `<=`[T](x, y: set[T]): bool {.magic: "LeSet", noSideEffect, ...raises: [],
                                       tags: [], forbids: [].}

  Returns true if `x` is a subset of `y`.

  A subset `x` has all of its members in `y` and `y` doesn't necessarily have more members than `x`. That is, `x` can be equal to `y`.

  Example:

      let
        a = {3, 5}
        b = {1, 3, 5, 7}
        c = {2}
      assert a <= b
      assert a <= a
      assert not (a <= c)

  Source Edit

    proc `<=%`(x, y: int): bool {.inline, ...raises: [], tags: [], forbids: [].}

  Treats `x` and `y` as unsigned and compares them. Returns true if `unsigned(x) <= unsigned(y)`. Source Edit

    proc `<=%`(x, y: int8): bool {.inline, ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `<=%`(x, y: int16): bool {.inline, ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `<=%`(x, y: int32): bool {.inline, ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `<=%`(x, y: int64): bool {.inline, ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `=`[T](dest: var T; src: T) {.noSideEffect, magic: "Asgn", ...raises: [],
                                       tags: [], forbids: [].}

  Source Edit

    proc `==`(x, y: bool): bool {.magic: "EqB", noSideEffect, ...raises: [], tags: [],
                                  forbids: [].}

  Checks for equality between two `bool` variables. Source Edit

    proc `==`(x, y: char): bool {.magic: "EqCh", noSideEffect, ...raises: [], tags: [],
                                  forbids: [].}

  Checks for equality between two `char` variables. Source Edit

    proc `==`(x, y: cstring): bool {.magic: "EqCString", noSideEffect, inline,
                                     ...raises: [], tags: [], forbids: [].}

  Checks for equality between two `cstring` variables. Source Edit

    proc `==`(x, y: float): bool {.magic: "EqF64", noSideEffect, ...raises: [],
                                   tags: [], forbids: [].}

  Source Edit

    proc `==`(x, y: float32): bool {.magic: "EqF64", noSideEffect, ...raises: [],
                                     tags: [], forbids: [].}

  Source Edit

    proc `==`(x, y: int): bool {.magic: "EqI", noSideEffect, ...raises: [], tags: [],
                                 forbids: [].}

  Compares two integers for equality. Source Edit

    proc `==`(x, y: int8): bool {.magic: "EqI", noSideEffect, ...raises: [], tags: [],
                                  forbids: [].}

  Source Edit

    proc `==`(x, y: int16): bool {.magic: "EqI", noSideEffect, ...raises: [], tags: [],
                                   forbids: [].}

  Source Edit

    proc `==`(x, y: int32): bool {.magic: "EqI", noSideEffect, ...raises: [], tags: [],
                                   forbids: [].}

  Source Edit

    proc `==`(x, y: int64): bool {.magic: "EqI", noSideEffect, ...raises: [], tags: [],
                                   forbids: [].}

  Source Edit

    proc `==`(x, y: pointer): bool {.magic: "EqRef", noSideEffect, ...raises: [],
                                     tags: [], forbids: [].}

  Checks for equality between two `pointer` variables.

  Example:

      var # this is a wildly dangerous example
        a = cast[pointer](0)
        b = cast[pointer](nil)
      assert a == b # true due to the special meaning of `nil`/0 as a pointer

  Source Edit

    proc `==`(x, y: string): bool {.magic: "EqStr", noSideEffect, ...raises: [],
                                    tags: [], forbids: [].}

  Checks for equality between two `string` variables. Source Edit

    proc `==`(x, y: uint): bool {.magic: "EqI", noSideEffect, ...raises: [], tags: [],
                                  forbids: [].}

  Compares two unsigned integers for equality. Source Edit

    proc `==`(x, y: uint8): bool {.magic: "EqI", noSideEffect, ...raises: [], tags: [],
                                   forbids: [].}

  Source Edit

    proc `==`(x, y: uint16): bool {.magic: "EqI", noSideEffect, ...raises: [],
                                    tags: [], forbids: [].}

  Source Edit

    proc `==`(x, y: uint32): bool {.magic: "EqI", noSideEffect, ...raises: [],
                                    tags: [], forbids: [].}

  Source Edit

    proc `==`(x, y: uint64): bool {.magic: "EqI", noSideEffect, ...raises: [],
                                    tags: [], forbids: [].}

  Source Edit

    proc `==`(x: string; y: typeof(nil) | typeof(nil)): bool {.
        error: "\'nil\' is invalid for \'string\'".}

  Source Edit

    proc `==`(x: typeof(nil) | typeof(nil); y: string): bool {.
        error: "\'nil\' is invalid for \'string\'".}

  Source Edit

    proc `==`[Enum: enum](x, y: Enum): bool {.magic: "EqEnum", noSideEffect,
        ...raises: [], tags: [], forbids: [].}

  Checks whether values within the same enum have the same underlying value.

  Example:

      type
        Enum1 = enum
          field1 = 3, field2
        Enum2 = enum
          place1, place2 = 3
      var
        e1 = field1
        e2 = place2.ord.Enum1
      assert e1 == e2
      assert not compiles(e1 == place2) # raises error

  Source Edit

    proc `==`[I, T](x, y: array[I, T]): bool

  Source Edit

    proc `==`[T: proc | iterator](x, y: T): bool {.magic: "EqProc", noSideEffect,
        ...raises: [], tags: [], forbids: [].}

  Checks that two `proc` variables refer to the same procedure. Source Edit

    proc `==`[T: tuple | object](x, y: T): bool

  Generic `==` operator for tuples that is lifted from the components. of `x` and `y`. Source Edit

    proc `==`[T](x, y: openArray[T]): bool

  Source Edit

    proc `==`[T](x, y: ptr T): bool {.magic: "EqRef", noSideEffect, ...raises: [],
                                      tags: [], forbids: [].}

  Checks that two `ptr` variables refer to the same item. Source Edit

    proc `==`[T](x, y: ref T): bool {.magic: "EqRef", noSideEffect, ...raises: [],
                                      tags: [], forbids: [].}

  Checks that two `ref` variables refer to the same item. Source Edit

    proc `==`[T](x, y: seq[T]): bool {.noSideEffect.}

  Generic equals operator for sequences: relies on a equals operator for the element type `T`. Source Edit

    proc `==`[T](x, y: set[T]): bool {.magic: "EqSet", noSideEffect, ...raises: [],
                                       tags: [], forbids: [].}

  Checks for equality between two variables of type `set`.

  Example:

      assert {1, 2, 2, 3} == {1, 2, 3} # duplication in sets is ignored

  Source Edit

    proc `=copy`[T](dest: var T; src: T) {.noSideEffect, magic: "Asgn", ...raises: [],
                                           tags: [], forbids: [].}

  Source Edit

    proc `=destroy`(x: string) {.inline, magic: "Destroy", enforceNoRaises,
                                 ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `=destroy`[T](x: ref T) {.inline, magic: "Destroy", ...raises: [], tags: [],
                                   forbids: [].}

  Source Edit

    proc `=destroy`[T](x: seq[T]) {.inline, magic: "Destroy", ...raises: [], tags: [],
                                    forbids: [].}

  Source Edit

    proc `=destroy`[T](x: var T) {.inline, magic: "Destroy", ...raises: [], tags: [],
                                   forbids: [].}

  Generic destructor implementation that can be overridden. Source Edit

    proc `=dup`[T](x: T): T {.inline, magic: "Dup", ...raises: [], tags: [],
                              forbids: [].}

  Generic dup implementation that can be overridden. Source Edit

    proc `=sink`[T](x: var T; y: T) {.inline, nodestroy, magic: "Asgn", ...raises: [],
                                      tags: [], forbids: [].}

  Generic sink implementation that can be overridden. Source Edit

    proc `=trace`[T](x: var T; env: pointer) {.inline, magic: "Trace", ...raises: [],
        tags: [], forbids: [].}

  Generic trace implementation that can be overridden. Source Edit

    proc `=wasMoved`[T](obj: var T) {.magic: "WasMoved", noSideEffect, ...raises: [],
                                      tags: [], forbids: [].}

  Generic wasMoved implementation that can be overridden. Source Edit

    proc `@`[IDX, T](a: sink array[IDX, T]): seq[T] {.magic: "ArrToSeq",
        noSideEffect, ...raises: [], tags: [], forbids: [].}

  Turns an array into a sequence.

  This most often useful for constructing sequences with the array constructor: `@[1, 2, 3]` has the type `seq[int]`, while `[1, 2, 3]` has the type `array[0..2, int]`.

      let
        a = [1, 3, 5]
        b = "foo"

      echo @a # => @[1, 3, 5]
      echo @b # => @['f', 'o', 'o']

  Source Edit

    proc `@`[T](a: openArray[T]): seq[T] {.magic: "OpenArrayToSeq", ...raises: [],
                                           tags: [], forbids: [].}

  Turns an openArray into a sequence.

  This is not as efficient as turning a fixed length array into a sequence as it always copies every element of `a`.

  Source Edit

    proc `[]`(s: string; i: BackwardsIndex): char {.inline, systemRaisesDefect,
        ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `[]`(s: var string; i: BackwardsIndex): var char {.inline,
        systemRaisesDefect, ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `[]`[I: Ordinal; T](a: T; i: I): T {.noSideEffect, magic: "ArrGet",
        ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `[]`[Idx, T; U, V: Ordinal](a: array[Idx, T]; x: HSlice[U, V]): seq[T] {.
        systemRaisesDefect.}

  Slice operation for arrays. Returns the inclusive range `[a[x.a], a[x.b]]`:

      var a = [1, 2, 3, 4]
      assert a[0..2] == @[1, 2, 3]

  See also:

  - toOpenArray(array[I, T];I,I)
  Source Edit

    proc `[]`[Idx, T](a: array[Idx, T]; i: BackwardsIndex): T {.inline,
        systemRaisesDefect.}

  Source Edit

    proc `[]`[Idx, T](a: var array[Idx, T]; i: BackwardsIndex): var T {.inline,
        systemRaisesDefect.}

  Source Edit

    proc `[]`[T, U: Ordinal](s: string; x: HSlice[T, U]): string {.inline,
        systemRaisesDefect.}

  Slice operation for strings. Returns the inclusive range `[s[x.a], s[x.b]]`:

      var s = "abcdef"
      assert s[1..3] == "bcd"

  Source Edit

    proc `[]`[T; U, V: Ordinal](s: openArray[T]; x: HSlice[U, V]): seq[T] {.
        systemRaisesDefect.}

  Slice operation for sequences. Returns the inclusive range `[s[x.a], s[x.b]]`:

      var s = @[1, 2, 3, 4]
      assert s[0..2] == @[1, 2, 3]

  See also:

  - toOpenArray(openArray[T];int,int)
  Source Edit

    proc `[]`[T](s: openArray[T]; i: BackwardsIndex): T {.inline, systemRaisesDefect.}

  Source Edit

    proc `[]`[T](s: var openArray[T]; i: BackwardsIndex): var T {.inline,
        systemRaisesDefect.}

  Source Edit

    proc `[]=`(s: var string; i: BackwardsIndex; x: char) {.inline,
        systemRaisesDefect, ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `[]=`[I: Ordinal; T, S](a: T; i: I; x: sink S) {.noSideEffect,
        magic: "ArrPut", ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `[]=`[Idx, T; U, V: Ordinal](a: var array[Idx, T]; x: HSlice[U, V];
                                      b: openArray[T]) {.systemRaisesDefect.}

  Slice assignment for arrays.

      var a = [10, 20, 30, 40, 50]
      a[1..2] = @[99, 88]
      assert a == [10, 99, 88, 40, 50]

  Source Edit

    proc `[]=`[Idx, T](a: var array[Idx, T]; i: BackwardsIndex; x: T) {.inline,
        systemRaisesDefect.}

  Source Edit

    proc `[]=`[T, U: Ordinal](s: var string; x: HSlice[T, U]; b: string) {.
        systemRaisesDefect.}

  Slice assignment for strings.

  If `b.len` is not exactly the number of elements that are referred to by `x`, a splice is performed:

  Example:

      var s = "abcdefgh"
      s[1 .. ^2] = "xyz"
      assert s == "axyzh"

  Source Edit

    proc `[]=`[T; U, V: Ordinal](s: var seq[T]; x: HSlice[U, V]; b: openArray[T]) {.
        systemRaisesDefect.}

  Slice assignment for sequences.

  If `b.len` is not exactly the number of elements that are referred to by `x`, a splice is performed.

  Example:

      var s = @"abcdefgh"
      s[1 .. ^2] = @"xyz"
      assert s == @"axyzh"

  Source Edit

    proc `[]=`[T](s: var openArray[T]; i: BackwardsIndex; x: T) {.inline,
        systemRaisesDefect.}

  Source Edit

    func abs(x: int): int {.magic: "AbsI", inline, ...raises: [], tags: [], forbids: [].}

  Source Edit

    func abs(x: int8): int8 {.magic: "AbsI", inline, ...raises: [], tags: [],
                              forbids: [].}

  Source Edit

    func abs(x: int16): int16 {.magic: "AbsI", inline, ...raises: [], tags: [],
                                forbids: [].}

  Source Edit

    func abs(x: int32): int32 {.magic: "AbsI", inline, ...raises: [], tags: [],
                                forbids: [].}

  Source Edit

    func abs(x: int64): int64 {.magic: "AbsI", inline, ...raises: [], tags: [],
                                forbids: [].}

  Returns the absolute value of `x`.

  If `x` is `low(x)` (that is -MININT for its type), an overflow exception is thrown (if overflow checking is turned on).

  Source Edit

    proc abs[T: float64 | float32](x: T): T {.noSideEffect, inline.}

  Source Edit

    proc add(x: var cstring; y: cstring) {.magic: "AppendStrStr", ...raises: [],
                                           tags: [], forbids: [].}

  Appends `y` to `x` in place. Only implemented for JS backend.

  Example:

      when defined(js):
        var tmp: cstring = ""
        tmp.add(cstring("ab"))
        tmp.add(cstring("cd"))
        doAssert tmp == cstring("abcd")

  Source Edit

    proc add(x: var string; y: char) {.magic: "AppendStrCh", noSideEffect,
                                       ...raises: [], tags: [], forbids: [].}

  Appends `y` to `x` in place.

      var tmp = ""
      tmp.add('a')
      tmp.add('b')
      assert(tmp == "ab")

  Source Edit

    proc add(x: var string; y: cstring) {.asmNoStackFrame, ...raises: [], tags: [],
                                          forbids: [].}

  Appends `y` to `x` in place.

  Example:

      var tmp = ""
      tmp.add(cstring("ab"))
      tmp.add(cstring("cd"))
      doAssert tmp == "abcd"

  Source Edit

    proc add(x: var string; y: string) {.magic: "AppendStrStr", noSideEffect,
                                         ...raises: [], tags: [], forbids: [].}

  Concatenates `x` and `y` in place.

  See also `strbasics.add`.

  Example:

      var tmp = ""
      tmp.add("ab")
      tmp.add("cd")
      assert tmp == "abcd"

  Source Edit

    proc add[T](x: var seq[T]; y: openArray[T]) {.noSideEffect.}

  Generic proc for adding a container `y` to a container `x`.

  For containers that have an order, `add` means append. New generic containers should also call their adding proc `add` for consistency. Generic code becomes much easier to write if the Nim naming scheme is respected.

  See also:

  - & proc

  Example:

      var a = @["a1", "a2"]
      a.add(["b1", "b2"])
      assert a == @["a1", "a2", "b1", "b2"]
      var c = @["c0", "c1", "c2", "c3"]
      a.add(c.toOpenArray(1, 2))
      assert a == @["a1", "a2", "b1", "b2", "c1", "c2"]

  Source Edit

    proc add[T](x: var seq[T]; y: sink T) {.magic: "AppendSeqElem", noSideEffect,
                                            nodestroy, ...raises: [], tags: [],
                                            forbids: [].}

  Generic proc for adding a data item `y` to a container `x`.

  For containers that have an order, `add` means append. New generic containers should also call their adding proc `add` for consistency. Generic code becomes much easier to write if the Nim naming scheme is respected.

  Source Edit

    proc addEscapedChar(s: var string; c: char) {.noSideEffect, inline, ...raises: [],
        tags: [], forbids: [].}

  Adds a char to string `s` and applies the following escaping:
  - replaces any `\` by `\\`
  - replaces any `'` by `\'`
  - replaces any `"` by `\"`
  - replaces any `\a` by `\\a`
  - replaces any `\b` by `\\b`
  - replaces any `\t` by `\\t`
  - replaces any `\n` by `\\n`
  - replaces any `\v` by `\\v`
  - replaces any `\f` by `\\f`
  - replaces any `\r` by `\\r`
  - replaces any `\e` by `\\e`
  - replaces any other character not in the set `{\21..\126}` by `\xHH` where `HH` is its hexadecimal value

  The procedure has been designed so that its output is usable for many different common syntaxes.

  Warning: This is not correct for producing ANSI C code!
  Source Edit

    proc addQuitProc(quitProc: proc () {.noconv.}) {.importc: "atexit",
        header: "<stdlib.h>", ...deprecated: "use exitprocs.addExitProc", raises: [],
        tags: [], forbids: [].}

  Deprecated: use exitprocs.addExitProc

  Adds/registers a quit procedure.

  Each call to `addQuitProc` registers another quit procedure. Up to 30 procedures can be registered. They are executed on a last-in, first-out basis (that is, the last function registered is the first to be executed). `addQuitProc` raises an EOutOfIndex exception if `quitProc` cannot be registered.

  Source Edit

    proc addQuoted[T](s: var string; x: T)

  Appends `x` to string `s` in place, applying quoting and escaping if `x` is a string or char.

  See addEscapedChar for the escaping scheme. When `x` is a string, characters in the range `{\128..\255}` are never escaped so that multibyte UTF-8 characters are untouched (note that this behavior is different from `addEscapedChar`).

  The Nim standard library uses this function on the elements of collections when producing a string representation of a collection. It is recommended to use this function as well for user-side collections. Users may overload `addQuoted` for custom (string-like) types if they want to implement a customized element representation.

      var tmp = ""
      tmp.addQuoted(1)
      tmp.add(", ")
      tmp.addQuoted("string")
      tmp.add(", ")
      tmp.addQuoted('c')
      assert(tmp == """1, "string", 'c'""")

  Source Edit

    proc `addr`[T](x: T): ptr T {.magic: "Addr", noSideEffect, ...raises: [], tags: [],
                                  forbids: [].}

  Builtin `addr` operator for taking the address of a memory location.
  Note: This works for `let` variables or parameters for better interop with C. When you use it to write a wrapper for a C library and take the address of `let` variables or parameters, you should always check that the original library does never write to data behind the pointer that is returned from this procedure.

  Cannot be overloaded.

      var
        buf: seq[char] = @['a','b','c']
        p = buf[1].addr
      echo p.repr # ref 0x7faa35c40059 --> 'b'
      echo p[]    # b

  Source Edit

    proc alignof(x: typedesc): int {.magic: "AlignOf", noSideEffect, ...raises: [],
                                     tags: [], forbids: [].}

  Source Edit

    proc alignof[T](x: T): int {.magic: "AlignOf", noSideEffect, ...raises: [],
                                 tags: [], forbids: [].}

  Source Edit

    proc alloc0Impl(size: Natural): pointer {.noconv, ...gcsafe, tags: [], gcsafe,
        raises: [], forbids: [].}

  Source Edit

    proc allocCStringArray(a: openArray[string]): cstringArray {....raises: [],
        tags: [], forbids: [].}

  Creates a NULL terminated cstringArray from `a`. The result has to be freed with `deallocCStringArray` after it's not needed anymore. Source Edit

    proc allocImpl(size: Natural): pointer {.noconv, ...gcsafe, tags: [], gcsafe,
        raises: [], forbids: [].}

  Source Edit

    proc allocShared0Impl(size: Natural): pointer {.noconv, ...gcsafe, gcsafe,
        raises: [], tags: [], forbids: [].}

  Source Edit

    proc allocSharedImpl(size: Natural): pointer {.noconv, compilerproc, ...gcsafe,
        gcsafe, raises: [], tags: [], forbids: [].}

  Source Edit

    proc `and`(a, b: typedesc): typedesc {.magic: "TypeTrait", noSideEffect,
                                           ...raises: [], tags: [], forbids: [].}

  Constructs an `and` meta class. Source Edit

    proc `and`(x, y: bool): bool {.magic: "And", noSideEffect, ...raises: [], tags: [],
                                   forbids: [].}

  Boolean `and`; returns true if `x == y == true` (if both arguments are true).

  Evaluation is lazy: if `x` is false, `y` will not even be evaluated.

  Source Edit

    proc `and`(x, y: int): int {.magic: "BitandI", noSideEffect, ...raises: [],
                                 tags: [], forbids: [].}

  Computes the `bitwise and` of numbers `x` and `y`.

  Example:

      assert (0b0011 and 0b0101) == 0b0001
      assert (0b0111 and 0b1100) == 0b0100

  Source Edit

    proc `and`(x, y: int8): int8 {.magic: "BitandI", noSideEffect, ...raises: [],
                                   tags: [], forbids: [].}

  Source Edit

    proc `and`(x, y: int16): int16 {.magic: "BitandI", noSideEffect, ...raises: [],
                                     tags: [], forbids: [].}

  Source Edit

    proc `and`(x, y: int32): int32 {.magic: "BitandI", noSideEffect, ...raises: [],
                                     tags: [], forbids: [].}

  Source Edit

    proc `and`(x, y: int64): int64 {.magic: "BitandI", noSideEffect, ...raises: [],
                                     tags: [], forbids: [].}

  Source Edit

    proc `and`(x, y: uint): uint {.magic: "BitandI", noSideEffect, ...raises: [],
                                   tags: [], forbids: [].}

  Computes the `bitwise and` of numbers `x` and `y`. Source Edit

    proc `and`(x, y: uint8): uint8 {.magic: "BitandI", noSideEffect, ...raises: [],
                                     tags: [], forbids: [].}

  Source Edit

    proc `and`(x, y: uint16): uint16 {.magic: "BitandI", noSideEffect, ...raises: [],
                                       tags: [], forbids: [].}

  Source Edit

    proc `and`(x, y: uint32): uint32 {.magic: "BitandI", noSideEffect, ...raises: [],
                                       tags: [], forbids: [].}

  Source Edit

    proc `and`(x, y: uint64): uint64 {.magic: "BitandI", noSideEffect, ...raises: [],
                                       tags: [], forbids: [].}

  Source Edit

    proc arrayWith[T](y: T; size: static int): array[size, T] {.noinit, nodestroy,
        ...raises: [].}

  Creates a new array filled with `y`. Source Edit

    proc arrayWithDefault[T](size: static int): array[size, T] {.noinit, nodestroy,
        ...raises: [].}

  Creates a new array filled with `default(T)`. Source Edit

    proc ashr(x: int8; y: SomeInteger): int8 {.magic: "AshrI", noSideEffect,
        ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc ashr(x: int16; y: SomeInteger): int16 {.magic: "AshrI", noSideEffect,
        ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc ashr(x: int32; y: SomeInteger): int32 {.magic: "AshrI", noSideEffect,
        ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc ashr(x: int64; y: SomeInteger): int64 {.magic: "AshrI", noSideEffect,
        ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc ashr(x: int; y: SomeInteger): int {.magic: "AshrI", noSideEffect,
        ...raises: [], tags: [], forbids: [].}

  Shifts right by pushing copies of the leftmost bit in from the left, and let the rightmost bits fall off. `y` (the number of positions to shift) is reduced to modulo `sizeof(x) * 8`. That is `ashr(15'i32, 35)` is equivalent to `ashr(15'i32, 3)`.

  Note that `ashr` is not an operator so use the normal function call syntax for it.

  See also:

  - shr func

  Example:

      assert ashr(0b0001_0000'i8, 2) == 0b0000_0100'i8
      assert ashr(0b1000_0000'i8, 8) == 0b1000_0000'i8
      assert ashr(0b1000_0000'i8, 1) == 0b1100_0000'i8

  Source Edit

    proc astToStr[T](x: T): string {.magic: "AstToStr", noSideEffect, ...raises: [],
                                     tags: [], forbids: [].}

  Converts the AST of `x` into a string representation. This is very useful for debugging. Source Edit

    func capacity(self: string): int {.inline, ...raises: [], tags: [], forbids: [].}

  Returns the current capacity of the string.

  Example:

      var str = newStringOfCap(cap = 42)
      str.add "Nim"
      assert str.capacity == 42

  Source Edit

    func capacity[T](self: seq[T]): int {.inline.}

  Returns the current capacity of the seq.

  Example:

      var lst = newSeqOfCap[string](cap = 42)
      lst.add "Nim"
      assert lst.capacity == 42

  Source Edit

    func card[T](x: set[T]): int {.magic: "Card", ...raises: [], tags: [], forbids: [].}

  Returns the cardinality of the set `x`, i.e. the number of elements in the set.

  Example:

      var a = {1, 3, 5, 7}
      assert card(a) == 4
      var b = {1, 3, 5, 7, 5}
      assert card(b) == 4 # repeated 5 doesn't count

  Source Edit

    func chr(u: range[0 .. 255]): char {.magic: "Chr", ...raises: [], tags: [],
                                         forbids: [].}

  Converts `u` to a `char`, same as `char(u)`.

  Example:

      doAssert chr(65) == 'A'
      doAssert chr(255) == '\255'
      doAssert chr(255) == char(255)
      doAssert not compiles chr(256)
      doAssert not compiles char(256)
      var x = 256
      doAssertRaises(RangeDefect): discard chr(x)
      doAssertRaises(RangeDefect): discard char(x)

  Source Edit

    proc clamp[T](x, a, b: T): T

  Limits the value `x` within the interval [a, b]. This proc is equivalent to but faster than `max(a, min(b, x))`.
  Warning: `a <= b` is assumed and will not be checked (currently).

  See also: `math.clamp` for a version that takes a `Slice[T]` instead.

  Example:

      assert (1.4).clamp(0.0, 1.0) == 1.0
      assert (0.5).clamp(0.0, 1.0) == 0.5
      assert 4.clamp(1, 3) == max(1, min(3, 4))

  Source Edit

    proc close[TMsg](c: var Channel[TMsg]) {....raises: [], gcsafe.}

  Closes a channel `c` and frees its associated resources. Source Edit

    proc cmp(x, y: string): int {.noSideEffect, ...raises: [], tags: [], forbids: [].}

  Compare proc for strings. More efficient than the generic version.

  Note: The precise result values depend on the used C runtime library and can differ between operating systems!

  Source Edit

    proc cmp[T](x, y: T): int

  Generic compare proc.

  Returns:

  - a value less than zero, if `x < y`
  - a value greater than zero, if `x > y`
  - zero, if `x == y`

  This is useful for writing generic algorithms without performance loss. This generic implementation uses the `==` and `<` operators.

      import std/algorithm
      echo sorted(@[4, 2, 6, 5, 8, 7], cmp[int])

  Source Edit

    proc cmpMem(a, b: pointer; size: Natural): int {.inline, noSideEffect, ...tags: [],
        raises: [], enforceNoRaises, ...forbids: [].}

  Compares the memory blocks `a` and `b`. `size` bytes will be compared.

  Returns:

  - a value less than zero, if `a < b`
  - a value greater than zero, if `a > b`
  - zero, if `a == b`

  Like any procedure dealing with raw memory this is unsafe.

  Source Edit

    proc compileOption(option, arg: string): bool {.magic: "CompileOptionArg",
        noSideEffect, ...raises: [], tags: [], forbids: [].}

  Can be used to determine an enum compile-time option.

  See also:

  - compileOption for `on|off` options
  - defined
  - std/compilesettings module

  Example:

      when compileOption("opt", "size") and compileOption("gc", "boehm"):
        discard "compiled with optimization for size and uses Boehm's GC"

  Source Edit

    proc compileOption(option: string): bool {.magic: "CompileOption", noSideEffect,
        ...raises: [], tags: [], forbids: [].}

  Can be used to determine an `on|off` compile-time option.

  See also:

  - compileOption for enum options
  - defined
  - std/compilesettings module

  Example: cmd: --floatChecks:off

      static: doAssert not compileOption("floatchecks")
      {.push floatChecks: on.}
      static: doAssert compileOption("floatchecks")
      # floating point NaN and Inf checks enabled in this scope
      {.pop.}

  Source Edit

    proc compiles(x: untyped): bool {.magic: "Compiles", noSideEffect, compileTime,
                                      ...raises: [], tags: [], forbids: [].}

  Special compile-time procedure that checks whether `x` can be compiled without any semantic error. This can be used to check whether a type supports some operation:

      when compiles(3 + 4):
        echo "'+' for integers is available"

  Source Edit

    proc contains[T](a: openArray[T]; item: T): bool {.inline.}

  Returns true if `item` is in `a` or false if not found. This is a shortcut for `find(a, item) >= 0`.

  This allows the `in` operator: `a.contains(item)` is the same as `item in a`.

      var a = @[1, 3, 5]
      assert a.contains(5)
      assert 3 in a
      assert 99 notin a

  Source Edit

    func contains[T](x: set[T]; y: T): bool {.magic: "InSet", ...raises: [], tags: [],
        forbids: [].}

  One should overload this proc if one wants to overload the `in` operator.

  The parameters are in reverse order! `a in b` is a template for `contains(b, a)`. This is because the unification algorithm that Nim uses for overload resolution works from left to right. But for the `in` operator that would be the wrong direction for this piece of code:

  Example:

      var s: set[range['a'..'z']] = {'a'..'c'}
      assert s.contains('c')
      assert 'b' in s
      assert 'd' notin s
      assert set['a'..'z'] is set[range['a'..'z']]

  If `in` had been declared as `[T](elem: T, s: set[T])` then `T` would have been bound to `char`. But `s` is not compatible to type `set[char]`! The solution is to bind `T` to `range['a'..'z']`. This is achieved by reversing the parameters for `contains`; `in` then passes its arguments in reverse order. Source Edit

    proc contains[U, V, W](s: HSlice[U, V]; value: W): bool {.noSideEffect, inline.}

  Checks if `value` is within the range of `s`; returns true if `value >= s.a and value <= s.b`.

      assert((1..3).contains(1) == true)
      assert((1..3).contains(2) == true)
      assert((1..3).contains(4) == false)

  Source Edit

    proc copyMem(dest, source: pointer; size: Natural) {.inline, ...gcsafe, tags: [],
        raises: [], enforceNoRaises, ...forbids: [].}

  Copies the contents from the memory at `source` to the memory at `dest`. Exactly `size` bytes will be copied. The memory regions may not overlap. Like any procedure dealing with raw memory this is unsafe. Source Edit

    proc create(T: typedesc; size = 1.Positive): ptr T:type {.inline, ...gcsafe,
        raises: [].}

  Allocates a new memory block with at least `T.sizeof * size` bytes.

  The block has to be freed with resize(block, 0) or dealloc(block). The block is initialized with all bytes containing zero, so it is somewhat safer than createU.

  The allocated memory belongs to its allocating thread! Use createShared to allocate from a shared heap.

  Source Edit

    proc createShared(T: typedesc; size = 1.Positive): ptr T:type {.inline.}

  Allocates a new memory block on the shared heap with at least `T.sizeof * size` bytes.

  The block has to be freed with resizeShared(block, 0) or freeShared(block).

  The block is initialized with all bytes containing zero, so it is somewhat safer than createSharedU.

  Source Edit

    proc createSharedU(T: typedesc; size = 1.Positive): ptr T:type {.inline,
        ...tags: [], gcsafe, raises: [].}

  Allocates a new memory block on the shared heap with at least `T.sizeof * size` bytes.

  The block has to be freed with resizeShared(block, 0) or freeShared(block).

  The block is not initialized, so reading from it before writing to it is undefined behaviour!

  See also:

  - createShared
  Source Edit

    proc createU(T: typedesc; size = 1.Positive): ptr T:type {.inline, ...gcsafe,
        raises: [].}

  Allocates a new memory block with at least `T.sizeof * size` bytes.

  The block has to be freed with resize(block, 0) or dealloc(block). The block is not initialized, so reading from it before writing to it is undefined behaviour!

  The allocated memory belongs to its allocating thread! Use createSharedU to allocate from a shared heap.

  See also:

  - create
  Source Edit

    proc cstringArrayToSeq(a: cstringArray): seq[string] {....raises: [], tags: [],
        forbids: [].}

  Converts a `cstringArray` to a `seq[string]`. `a` is supposed to be terminated by `nil`. Source Edit

    proc cstringArrayToSeq(a: cstringArray; len: Natural): seq[string] {....raises: [],
        tags: [], forbids: [].}

  Converts a `cstringArray` to a `seq[string]`. `a` is supposed to be of length `len`. Source Edit

    proc dealloc(p: pointer) {.noconv, compilerproc, ...gcsafe, gcsafe, raises: [],
                               tags: [], forbids: [].}

  Frees the memory allocated with `alloc`, `alloc0`, `realloc`, `create` or `createU`.

  This procedure is dangerous! If one forgets to free the memory a leak occurs; if one tries to access freed memory (or just freeing it twice!) a core dump may happen or other memory may be corrupted.

  The freed memory must belong to its allocating thread! Use deallocShared to deallocate from a shared heap.

  Source Edit

    proc deallocCStringArray(a: cstringArray) {....raises: [], tags: [], forbids: [].}

  Frees a NULL terminated cstringArray. Source Edit

    proc deallocImpl(p: pointer) {.noconv, ...gcsafe, tags: [], gcsafe, raises: [],
                                   forbids: [].}

  Source Edit

    proc deallocShared(p: pointer) {.noconv, compilerproc, ...gcsafe, gcsafe,
                                     raises: [], tags: [], forbids: [].}

  Frees the memory allocated with `allocShared`, `allocShared0` or `reallocShared`.

  This procedure is dangerous! If one forgets to free the memory a leak occurs; if one tries to access freed memory (or just freeing it twice!) a core dump may happen or other memory may be corrupted.

  Source Edit

    proc deallocSharedImpl(p: pointer) {.noconv, ...gcsafe, gcsafe, raises: [],
                                         tags: [], forbids: [].}

  Source Edit

    proc debugEcho(x: varargs[typed, `$`]) {.magic: "Echo", noSideEffect, ...tags: [],
        raises: [], forbids: [].}

  Same as echo, but as a special semantic rule, `debugEcho` pretends to be free of side effects, so that it can be used for debugging routines marked as noSideEffect. Source Edit

    proc dec[T: Ordinal; V: SomeInteger](x: var T; y: V = 1) {.magic: "Dec",
        noSideEffect, ...raises: [], tags: [], forbids: [].}

  Decrements the ordinal `x` by `y`.

  If such a value does not exist, `OverflowDefect` is raised or a compile time error occurs. This is a short notation for: `x = pred(x, y)`.

  Example:

      var i = 2
      dec(i)
      assert i == 1
      dec(i, 3)
      assert i == -2

  Source Edit

    proc declared(x: untyped): bool {.magic: "Declared", noSideEffect, compileTime,
                                      ...raises: [], tags: [], forbids: [].}

  Special compile-time procedure that checks whether `x` is declared. `x` has to be an identifier or a qualified identifier.

  This can be used to check whether a library provides a certain feature or not:

      when not declared(strutils.toUpper):
        # provide our own toUpper proc here, because strutils is
        # missing it.

  See also:

  - declaredInScope
  Source Edit

    proc declaredInScope(x: untyped): bool {.magic: "DeclaredInScope", noSideEffect,
        compileTime, ...raises: [], tags: [], forbids: [].}

  Special compile-time procedure that checks whether `x` is declared in the current scope. `x` has to be an identifier. Source Edit

    proc deepCopy[T](x: out T; y: T) {.noSideEffect, magic: "DeepCopy", ...raises: [],
                                       tags: [], forbids: [].}

  Performs a deep copy of `y` and copies it into `x`.

  This is also used by the code generator for the implementation of `spawn`.

  For `--mm:arc` or `--mm:orc` deepcopy support has to be enabled via `--deepcopy:on`.

  Source Edit

    proc deepCopy[T](y: T): T

  Convenience wrapper around `deepCopy` overload. Source Edit

    proc default[T](_: typedesc[T]): T {.magic: "Default", noSideEffect, ...raises: [],
                                         tags: [], forbids: [].}

  Returns the default value of the type `T`. Contrary to `zeroDefault`, it takes default fields of an object into consideration.

  See also:

  - zeroDefault

  Example: cmd: -d:nimPreviewRangeDefault

      assert (int, float).default == (0, 0.0)
      type Foo = object
        a: range[2..6]
      var x = Foo.default
      assert x.a == 2

  Source Edit

    proc defined(x: untyped): bool {.magic: "Defined", noSideEffect, compileTime,
                                     ...raises: [], tags: [], forbids: [].}

  Special compile-time procedure that checks whether `x` is defined.

  `x` is an external symbol introduced through the compiler's -d:x switch to enable build time conditionals:

      when not defined(release):
        # Do here programmer friendly expensive sanity checks.
      # Put here the normal code

  See also:

  - compileOption for `on|off` options
  - compileOption for enum options
  - define pragmas
  Source Edit

    proc del[T](x: var seq[T]; i: Natural) {.noSideEffect.}

  Deletes the item at index `i` by putting `x[high(x)]` into position `i`.

  This is an `O(1)` operation.

  See also:

  - delete for preserving the order

  Example:

      var a = @[10, 11, 12, 13, 14]
      a.del(2)
      assert a == @[10, 11, 14, 13]

  Source Edit

    proc delete[T](x: var seq[T]; i: Natural) {.noSideEffect, systemRaisesDefect.}

  Deletes the item at index `i` by moving all `x[i+1..^1]` items by one position.

  This is an `O(n)` operation.

  See also:

  - del for O(1) operation

  Example:

      var s = @[1, 2, 3, 4, 5]
      s.delete(2)
      doAssert s == @[1, 2, 4, 5]

  Source Edit

    proc dispose(x: ForeignCell) {....raises: [], tags: [], forbids: [].}

  Source Edit

    proc `div`(x, y: int): int {.magic: "DivI", noSideEffect, ...raises: [], tags: [],
                                 forbids: [].}

  Computes the integer division.

  This is roughly the same as `math.trunc(x/y).int`.

  Example:

      assert (1 div 2) == 0
      assert (2 div 2) == 1
      assert (3 div 2) == 1
      assert (7 div 3) == 2
      assert (-7 div 3) == -2
      assert (7 div -3) == -2
      assert (-7 div -3) == 2

  Source Edit

    proc `div`(x, y: int8): int8 {.magic: "DivI", noSideEffect, ...raises: [],
                                   tags: [], forbids: [].}

  Source Edit

    proc `div`(x, y: int16): int16 {.magic: "DivI", noSideEffect, ...raises: [],
                                     tags: [], forbids: [].}

  Source Edit

    proc `div`(x, y: int32): int32 {.magic: "DivI", noSideEffect, ...raises: [],
                                     tags: [], forbids: [].}

  Source Edit

    proc `div`(x, y: int64): int64 {.magic: "DivI", noSideEffect, ...raises: [],
                                     tags: [], forbids: [].}

  Source Edit

    proc `div`(x, y: uint): uint {.magic: "DivU", noSideEffect, ...raises: [],
                                   tags: [], forbids: [].}

  Computes the integer division for unsigned integers. This is roughly the same as `trunc(x/y)`. Source Edit

    proc `div`(x, y: uint8): uint8 {.magic: "DivU", noSideEffect, ...raises: [],
                                     tags: [], forbids: [].}

  Source Edit

    proc `div`(x, y: uint16): uint16 {.magic: "DivU", noSideEffect, ...raises: [],
                                       tags: [], forbids: [].}

  Source Edit

    proc `div`(x, y: uint32): uint32 {.magic: "DivU", noSideEffect, ...raises: [],
                                       tags: [], forbids: [].}

  Source Edit

    proc `div`(x, y: uint64): uint64 {.magic: "DivU", noSideEffect, ...raises: [],
                                       tags: [], forbids: [].}

  Source Edit

    proc echo(x: varargs[typed, `$`]) {.magic: "Echo", ...gcsafe, sideEffect,
                                        ...raises: [], tags: [], forbids: [].}

  Writes and flushes the parameters to the standard output.

  Special built-in that takes a variable number of arguments. Each argument is converted to a string via `$`, so it works for user-defined types that have an overloaded `$` operator. It is roughly equivalent to `writeLine(stdout, x); flushFile(stdout)`, but available for the JavaScript target too.

  Unlike other IO operations this is guaranteed to be thread-safe as `echo` is very often used for debugging convenience. If you want to use `echo` inside a proc without side effects you can use debugEcho instead.

  Source Edit

    proc ensureMove[T](x: T): T {.magic: "EnsureMove", noSideEffect, ...raises: [],
                                  tags: [], forbids: [].}

  Ensures that `x` is moved to the new location, otherwise it gives an error at the compile time.

  Example:

      proc foo =
        var x = "Hello"
        let y = ensureMove(x)
        doAssert y == "Hello"
      foo()

  Source Edit

    proc equalMem(a, b: pointer; size: Natural): bool {.inline, noSideEffect,
        ...tags: [], raises: [], enforceNoRaises, ...forbids: [].}

  Compares the memory blocks `a` and `b`. `size` bytes will be compared.

  If the blocks are equal, `true` is returned, `false` otherwise. Like any procedure dealing with raw memory this is unsafe.

  Source Edit

    func excl[T](x: var set[T]; y: T) {.magic: "Excl", ...raises: [], tags: [],
                                        forbids: [].}

  Excludes element `y` from the set `x`.

  This is the same as `x = x - {y}`, but it might be more efficient.

  Example:

      var b = {2, 3, 5, 6, 12, 54}
      b.excl(5)
      assert b == {2, 3, 6, 12, 54}

  Source Edit

    proc find[T, S](a: T; item: S): int {.inline.}

  Returns the first index of `item` in `a` or -1 if not found. This requires appropriate `items` and `==` operations to work. Source Edit

    proc finished[T: iterator {.closure.}](x: T): bool {.noSideEffect, inline,
        magic: "Finished", ...raises: [], tags: [], forbids: [].}

  It can be used to determine if a first class iterator has finished. Source Edit

    proc freeShared[T](p: ptr T) {.inline, ...gcsafe, raises: [].}

  Frees the memory allocated with `createShared`, `createSharedU` or `resizeShared`.

  This procedure is dangerous! If one forgets to free the memory a leak occurs; if one tries to access freed memory (or just freeing it twice!) a core dump may happen or other memory may be corrupted.

  Source Edit

    proc GC_disableMarkAndSweep() {....raises: [], raises: [], tags: [], forbids: [].}

  For `--mm:orc` an alias for `GC_disableOrc`. Source Edit

    proc GC_disableOrc() {....raises: [], raises: [], tags: [], forbids: [].}

  Disables the cycle collector subsystem of `--mm:orc`. This is a `--mm:orc` specific API. Check with `when defined(gcOrc)` for its existence. Source Edit

    proc GC_enableMarkAndSweep() {....raises: [], raises: [], tags: [], forbids: [].}

  For `--mm:orc` an alias for `GC_enableOrc`. Source Edit

    proc GC_enableOrc() {....raises: [], raises: [], tags: [], forbids: [].}

  Enables the cycle collector subsystem of `--mm:orc`. This is a `--mm:orc` specific API. Check with `when defined(gcOrc)` for its existence. Source Edit

    proc GC_fullCollect() {....raises: [], raises: [], tags: [RootEffect], forbids: [].}

  Forces a full garbage collection pass. With `--mm:orc` triggers the cycle collector. This is an alias for `GC_runOrc`. Source Edit

    proc GC_getStatistics(): string {....raises: [], tags: [], forbids: [].}

  Source Edit

    proc GC_partialCollect(limit: int) {....raises: [], raises: [], tags: [RootEffect],
                                         forbids: [].}

  Source Edit

    proc GC_prepareOrc(): int {.inline, ...raises: [], raises: [], tags: [],
                                forbids: [].}

  Source Edit

    proc GC_ref[T](x: ref T) {....raises: [].}

  New runtime only supports this operation for 'ref T'. Source Edit

    proc GC_runOrc() {....raises: [], raises: [], tags: [RootEffect], forbids: [].}

  Forces a cycle collection pass. Source Edit

    proc GC_unref[T](x: ref T) {....raises: [].}

  New runtime only supports this operation for 'ref T'. Source Edit

    proc getAllocStats(): AllocStats {....raises: [], tags: [], forbids: [].}

  Source Edit

    proc getCurrentException(): ref Exception {.compilerproc, inline, ...gcsafe,
        raises: [], tags: [], forbids: [].}

  Retrieves the current exception; if there is none, `nil` is returned. Source Edit

    proc getCurrentExceptionMsg(): string {.inline, ...gcsafe, raises: [], tags: [],
                                            forbids: [].}

  Retrieves the error message that was attached to the current exception; if there is none, `""` is returned. Source Edit

    proc getFrame(): PFrame {.compilerproc, inline, ...raises: [], tags: [],
                              forbids: [].}

  Source Edit

    proc getFrameState(): FrameState {.compilerproc, inline, ...raises: [], tags: [],
                                       forbids: [].}

  Source Edit

    proc getFreeMem(): int {....gcsafe, raises: [], tags: [], forbids: [].}

  Returns the number of bytes that are owned by the process, but do not hold any meaningful data. Source Edit

    proc getFreeSharedMem(): int {....gcsafe, raises: [], tags: [], forbids: [].}

  Returns the number of bytes that are owned by the process on the shared heap, but do not hold any meaningful data. This is only available when threads are enabled. Source Edit

    proc getMaxMem(): int {....raises: [], tags: [], forbids: [].}

  Source Edit

    proc getOccupiedMem(): int {....gcsafe, raises: [], tags: [], forbids: [].}

  Returns the number of bytes that are owned by the process and hold data. Source Edit

    proc getOccupiedSharedMem(): int {....gcsafe, raises: [], tags: [], forbids: [].}

  Returns the number of bytes that are owned by the process on the shared heap and hold data. This is only available when threads are enabled. Source Edit

    proc getStackTrace(): string {....gcsafe, raises: [], tags: [], forbids: [].}

  Gets the current stack trace. This only works for debug builds. Source Edit

    proc getStackTrace(e: ref Exception): string {....gcsafe, raises: [], tags: [],
        forbids: [].}

  Gets the stack trace associated with `e`, which is the stack that lead to the `raise` statement. This only works for debug builds. Source Edit

    proc getStackTraceEntries(): seq[StackTraceEntry] {....raises: [], tags: [],
        forbids: [].}

  Returns the stack trace entries for the current stack trace. This is not yet available for the JS backend. Source Edit

    proc getStackTraceEntries(e: ref Exception): lent seq[StackTraceEntry] {.
        ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc getThreadId(): int {....raises: [], raises: [], tags: [], forbids: [].}

  Gets the ID of the currently running thread. Source Edit

    proc getTotalMem(): int {....gcsafe, raises: [], tags: [], forbids: [].}

  Returns the number of bytes that are owned by the process. Source Edit

    proc getTotalSharedMem(): int {....gcsafe, raises: [], tags: [], forbids: [].}

  Returns the number of bytes on the shared heap that are owned by the process. This is only available when threads are enabled. Source Edit

    proc getTypeInfo[T](x: T): pointer {.magic: "GetTypeInfo", ...gcsafe, raises: [],
                                         tags: [], forbids: [].}

  Get type information for `x`.

  Ordinary code should not use this, but the typeinfo module instead.

  Source Edit

    proc gorge(command: string; input = ""; cache = ""): string {.
        magic: "StaticExec", ...raises: [], tags: [], forbids: [].}

  This is an alias for staticExec. Source Edit

    proc gorgeEx(command: string; input = ""; cache = ""): tuple[output: string,
        exitCode: int] {.noinit, ...raises: [], tags: [], forbids: [].}

  Similar to gorge but also returns the precious exit code. Source Edit

    proc grow[T](x: var seq[T]; newLen: Natural; value: T) {.nodestroy.}

  Source Edit

    proc high(T: typedesc[SomeFloat]): T:type

  Source Edit

    proc high(x: cstring): int {.magic: "High", noSideEffect, ...raises: [], tags: [],
                                 forbids: [].}

  Returns the highest possible index of a compatible string `x`. This is sometimes an O(n) operation.

  See also:

  - low(cstring)
  Source Edit

    proc high(x: string): int {.magic: "High", noSideEffect, ...raises: [], tags: [],
                                forbids: [].}

  Returns the highest possible index of a string `x`.

      var str = "Hello world!"
      high(str) # => 11

  See also:

  - low(string)
  Source Edit

    proc high[I, T](x: array[I, T]): I {.magic: "High", noSideEffect, ...raises: [],
                                         tags: [], forbids: [].}

  Returns the highest possible index of an array `x`.

  For empty arrays, the return type is `int`.

      var arr = [1, 2, 3, 4, 5, 6, 7]
      high(arr) # => 6
      for i in low(arr)..high(arr):
        echo arr[i]

  See also:

  - low(array)
  Source Edit

    proc high[I, T](x: typedesc[array[I, T]]): I {.magic: "High", noSideEffect,
        ...raises: [], tags: [], forbids: [].}

  Returns the highest possible index of an array type.

  For empty arrays, the return type is `int`.

      high(array[7, int]) # => 6

  See also:

  - low(typedesc[array])
  Source Edit

    proc high[T: Ordinal | enum | range](x: T): T {.magic: "High", noSideEffect, ...deprecated: "Deprecated since v1.4; there should not be `high(value)`. Use `high(type)`.",
        raises: [], tags: [], forbids: [].}

  Deprecated: Deprecated since v1.4; there should not be `high(value)`. Use `high(type)`.

  Returns the highest possible value of an ordinal value `x`.

  As a special semantic rule, `x` may also be a type identifier.

  This proc is deprecated, use this one instead:

  - high(typedesc)

      high(2) # => 9223372036854775807

  Source Edit

    proc high[T: Ordinal | enum | range](x: typedesc[T]): T {.magic: "High",
        noSideEffect, ...raises: [], tags: [], forbids: [].}

  Returns the highest possible value of an ordinal or enum type.

  `high(int)` is Nim's way of writing INT_MAX or MAX_INT.

      high(int) # => 9223372036854775807

  See also:

  - low(typedesc)
  Source Edit

    proc high[T](x: openArray[T]): int {.magic: "High", noSideEffect, ...raises: [],
                                         tags: [], forbids: [].}

  Returns the highest possible index of a sequence `x`.

      var s = @[1, 2, 3, 4, 5, 6, 7]
      high(s) # => 6
      for i in low(s)..high(s):
        echo s[i]

  See also:

  - low(openArray)
  Source Edit

    proc inc[T: Ordinal; V: SomeInteger](x: var T; y: V = 1) {.magic: "Inc",
        noSideEffect, ...raises: [], tags: [], forbids: [].}

  Increments the ordinal `x` by `y`.

  If such a value does not exist, `OverflowDefect` is raised or a compile time error occurs. This is a short notation for: `x = succ(x, y)`.

  Example:

      var i = 2
      inc(i)
      assert i == 3
      inc(i, 3)
      assert i == 6

  Source Edit

    func incl[T](x: var set[T]; y: T) {.magic: "Incl", ...raises: [], tags: [],
                                        forbids: [].}

  Includes element `y` in the set `x`.

  This is the same as `x = x + {y}`, but it might be more efficient.

  Example:

      var a = {1, 3, 5}
      a.incl(2)
      assert a == {1, 2, 3, 5}
      a.incl(4)
      assert a == {1, 2, 3, 4, 5}

  Source Edit

    proc insert(x: var string; item: string; i = 0.Natural) {.noSideEffect,
        ...raises: [], tags: [], forbids: [].}

  Inserts `item` into `x` at position `i`.

      var a = "abc"
      a.insert("zz", 0) # a <- "zzabc"

  Source Edit

    proc insert[T](x: var seq[T]; item: sink T; i = 0.Natural) {.noSideEffect.}

  Inserts `item` into `x` at position `i`.

      var i = @[1, 3, 5]
      i.insert(99, 0) # i <- @[99, 1, 3, 5]

  Source Edit

    proc instantiationInfo(index = -1; fullPaths = false): tuple[filename: string,
        line: int, column: int] {.magic: "InstantiationInfo", noSideEffect,
                                  ...raises: [], tags: [], forbids: [].}

  Provides access to the compiler's instantiation stack line information of a template.

  While similar to the caller info of other languages, it is determined at compile time.

  This proc is mostly useful for meta programming (eg. `assert` template) to retrieve information about the current filename and line number. Example:

      import std/strutils

      template testException(exception, code: untyped): typed =
        try:
          let pos = instantiationInfo()
          discard(code)
          echo "Test failure at $1:$2 with '$3'" % [pos.filename,
            $pos.line, astToStr(code)]
          assert false, "A test expecting failure succeeded?"
        except exception:
          discard

      proc tester(pos: int): int =
        let
          a = @[1, 2, 3]
        result = a[pos]

      when isMainModule:
        testException(IndexDefect, tester(30))
        testException(IndexDefect, tester(1))
        # --> Test failure at example.nim:20 with 'tester(1)'

  Source Edit

    proc `is`[T, S](x: T; y: S): bool {.magic: "Is", noSideEffect, ...raises: [],
                                        tags: [], forbids: [].}

  Checks if `T` is of the same type as `S`.

  For a negated version, use isnot.

      assert 42 is int
      assert @[1, 2] is seq

      proc test[T](a: T): int =
        when (T is int):
          return a
        else:
          return 0

      assert(test[int](3) == 3)
      assert(test[string]("xyz") == 0)

  Source Edit

    proc isNil(x: cstring): bool {.noSideEffect, magic: "IsNil", ...raises: [],
                                   tags: [], forbids: [].}

  Source Edit

    proc isNil(x: pointer): bool {.noSideEffect, magic: "IsNil", ...raises: [],
                                   tags: [], forbids: [].}

  Source Edit

    proc isNil(x: string): bool {.noSideEffect,
                                  error: "\'isNil\' is invalid for \'string\'".}

  Source Edit

    proc isNil[T: proc | iterator {.closure.}](x: T): bool {.noSideEffect,
        magic: "IsNil", ...raises: [], tags: [], forbids: [].}

  Fast check whether `x` is nil. This is sometimes more efficient than `== nil`. Source Edit

    proc isNil[T](x: ptr T): bool {.noSideEffect, magic: "IsNil", ...raises: [],
                                    tags: [], forbids: [].}

  Source Edit

    proc isNil[T](x: ref T): bool {.noSideEffect, magic: "IsNil", ...raises: [],
                                    tags: [], forbids: [].}

  Source Edit

    proc isNotForeign(x: ForeignCell): bool {....raises: [], tags: [], forbids: [].}

  Source Edit

    proc isUniqueRef[T](x: ref T): bool {.inline, ...raises: [].}

  Returns true if the object `x` points to is uniquely referenced. Such an object can potentially be passed over to a different thread safely, if great care is taken. This queries the internal reference count of the object which is subject to lots of optimizations! In other words the value of `isUniqueRef` can depend on the used compiler version and optimizer setting. Nevertheless it can be used as a very valuable debugging tool and can be used to specify the constraints of a threading related API via `assert isUniqueRef(x)`. Source Edit

    proc iterToProc(iter: typed; envType: typedesc; procName: untyped) {.
        magic: "Plugin", compileTime, ...raises: [], tags: [], forbids: [].}

  Source Edit

    func len(x: (type array) | array): int {.magic: "LengthArray", ...raises: [],
        tags: [], forbids: [].}

  Returns the length of an array or an array type. This is roughly the same as `high(T)-low(T)+1`.

  Example:

      var a = [1, 1, 1]
      assert a.len == 3
      assert array[0, float].len == 0
      static: assert array[-2..2, float].len == 5

  Source Edit

    proc len(x: cstring): int {.magic: "LengthStr", noSideEffect, ...raises: [],
                                tags: [], forbids: [].}

  Returns the length of a compatible string. This is an O(n) operation except in js at runtime.

  Note: On the JS backend this currently counts UTF-16 code points instead of bytes at runtime (not at compile time). For now, if you need the byte length of the UTF-8 encoding, convert to string with `$` first then call `len`.

  Example:

      doAssert len(cstring"abc") == 3
      doAssert len(cstring r"ab\0c") == 5 # \0 is escaped
      doAssert len(cstring"ab\0c") == 5 # ditto
      var a: cstring = "ab\0c"
      when defined(js): doAssert a.len == 4 # len ignores \0 for js
      else: doAssert a.len == 2 # \0 is a null terminator
      static:
        var a2: cstring = "ab\0c"
        doAssert a2.len == 2 # \0 is a null terminator, even in js vm

  Source Edit

    func len(x: string): int {.magic: "LengthStr", ...raises: [], tags: [], forbids: [].}

  Returns the length of a string.

  Example:

      assert "abc".len == 3
      assert "".len == 0
      assert string.default.len == 0

  Source Edit

    func len[T](x: seq[T]): int {.magic: "LengthSeq", ...raises: [], tags: [],
                                  forbids: [].}

  Returns the length of `x`.

  Example:

      assert @[0, 1].len == 2
      assert seq[int].default.len == 0
      assert newSeq[int](3).len == 3
      let s = newSeqOfCap[int](3)
      assert s.len == 0

  Source Edit

    func len[T](x: set[T]): int {.magic: "Card", ...raises: [], tags: [], forbids: [].}

  An alias for `card(x)`. Source Edit

    func len[TOpenArray: openArray | varargs](x: TOpenArray): int {.
        magic: "LengthOpenArray", ...raises: [], tags: [], forbids: [].}

  Returns the length of an openArray.

  Example:

      proc bar[T](a: openArray[T]): int = len(a)
      assert bar([1,2]) == 2
      assert [1,2].len == 2

  Source Edit

    proc len[U: Ordinal; V: Ordinal](x: HSlice[U, V]): int {.noSideEffect, inline.}

  Length of ordinal slice. When x.b < x.a returns zero length.

      assert((0..5).len == 6)
      assert((5..2).len == 0)

  Source Edit

    proc locals(): RootObj {.magic: "Plugin", noSideEffect, ...raises: [], tags: [],
                             forbids: [].}

  Generates a tuple constructor expression listing all the local variables in the current scope.

  This is quite fast as it does not rely on any debug or runtime information. Note that in contrast to what the official signature says, the return type is not `RootObj` but a tuple of a structure that depends on the current scope. Example:

      proc testLocals() =
        var
          a = "something"
          b = 4
          c = locals()
          d = "super!"

        b = 1
        for name, value in fieldPairs(c):
          echo "name ", name, " with value ", value
        echo "B is ", b
      # -> name a with value something
      # -> name b with value 4
      # -> B is 1

  Source Edit

    proc low(T: typedesc[SomeFloat]): T:type

  Source Edit

    proc low(x: cstring): int {.magic: "Low", noSideEffect, ...raises: [], tags: [],
                                forbids: [].}

  Returns the lowest possible index of a compatible string `x`.

  See also:

  - high(cstring)
  Source Edit

    proc low(x: string): int {.magic: "Low", noSideEffect, ...raises: [], tags: [],
                               forbids: [].}

  Returns the lowest possible index of a string `x`.

      var str = "Hello world!"
      low(str) # => 0

  See also:

  - high(string)
  Source Edit

    proc low[I, T](x: array[I, T]): I {.magic: "Low", noSideEffect, ...raises: [],
                                        tags: [], forbids: [].}

  Returns the lowest possible index of an array `x`.

  For empty arrays, the return type is `int`.

      var arr = [1, 2, 3, 4, 5, 6, 7]
      low(arr) # => 0
      for i in low(arr)..high(arr):
        echo arr[i]

  See also:

  - high(array)
  Source Edit

    proc low[I, T](x: typedesc[array[I, T]]): I {.magic: "Low", noSideEffect,
        ...raises: [], tags: [], forbids: [].}

  Returns the lowest possible index of an array type.

  For empty arrays, the return type is `int`.

      low(array[7, int]) # => 0

  See also:

  - high(typedesc[array])
  Source Edit

    proc low[T: Ordinal | enum | range](x: T): T {.magic: "Low", noSideEffect, ...deprecated: "Deprecated since v1.4; there should not be `low(value)`. Use `low(type)`.",
        raises: [], tags: [], forbids: [].}

  Deprecated: Deprecated since v1.4; there should not be `low(value)`. Use `low(type)`.

  Returns the lowest possible value of an ordinal value `x`. As a special semantic rule, `x` may also be a type identifier.

  This proc is deprecated, use this one instead:

  - low(typedesc)

      low(2) # => -9223372036854775808

  Source Edit

    proc low[T: Ordinal | enum | range](x: typedesc[T]): T {.magic: "Low",
        noSideEffect, ...raises: [], tags: [], forbids: [].}

  Returns the lowest possible value of an ordinal or enum type.

  `low(int)` is Nim's way of writing INT_MIN or MIN_INT.

      low(int) # => -9223372036854775808

  See also:

  - high(typedesc)
  Source Edit

    proc low[T](x: openArray[T]): int {.magic: "Low", noSideEffect, ...raises: [],
                                        tags: [], forbids: [].}

  Returns the lowest possible index of a sequence `x`.

      var s = @[1, 2, 3, 4, 5, 6, 7]
      low(s) # => 0
      for i in low(s)..high(s):
        echo s[i]

  See also:

  - high(openArray)
  Source Edit

    proc max(x, y: float32): float32 {.noSideEffect, inline, ...raises: [], tags: [],
                                       forbids: [].}

  Source Edit

    proc max(x, y: float64): float64 {.noSideEffect, inline, ...raises: [], tags: [],
                                       forbids: [].}

  Source Edit

    proc max(x, y: int): int {.magic: "MaxI", noSideEffect, ...raises: [], tags: [],
                               forbids: [].}

  Source Edit

    proc max(x, y: int8): int8 {.magic: "MaxI", noSideEffect, ...raises: [], tags: [],
                                 forbids: [].}

  Source Edit

    proc max(x, y: int16): int16 {.magic: "MaxI", noSideEffect, ...raises: [],
                                   tags: [], forbids: [].}

  Source Edit

    proc max(x, y: int32): int32 {.magic: "MaxI", noSideEffect, ...raises: [],
                                   tags: [], forbids: [].}

  Source Edit

    proc max(x, y: int64): int64 {.magic: "MaxI", noSideEffect, ...raises: [],
                                   tags: [], forbids: [].}

  The maximum value of two integers. Source Edit

    proc max[T: not SomeFloat](x, y: T): T {.inline.}

  Generic maximum operator of 2 values based on `<=`. Source Edit

    proc max[T](x: openArray[T]): T

  The maximum value of `x`. `T` needs to have a `<` operator. Source Edit

    proc min(x, y: float32): float32 {.noSideEffect, inline, ...raises: [], tags: [],
                                       forbids: [].}

  Source Edit

    proc min(x, y: float64): float64 {.noSideEffect, inline, ...raises: [], tags: [],
                                       forbids: [].}

  Source Edit

    proc min(x, y: int): int {.magic: "MinI", noSideEffect, ...raises: [], tags: [],
                               forbids: [].}

  Source Edit

    proc min(x, y: int8): int8 {.magic: "MinI", noSideEffect, ...raises: [], tags: [],
                                 forbids: [].}

  Source Edit

    proc min(x, y: int16): int16 {.magic: "MinI", noSideEffect, ...raises: [],
                                   tags: [], forbids: [].}

  Source Edit

    proc min(x, y: int32): int32 {.magic: "MinI", noSideEffect, ...raises: [],
                                   tags: [], forbids: [].}

  Source Edit

    proc min(x, y: int64): int64 {.magic: "MinI", noSideEffect, ...raises: [],
                                   tags: [], forbids: [].}

  The minimum value of two integers. Source Edit

    proc min[T: not SomeFloat](x, y: T): T {.inline.}

  Generic minimum operator of 2 values based on `<=`. Source Edit

    proc min[T](x: openArray[T]): T

  The minimum value of `x`. `T` needs to have a `<` operator. Source Edit

    proc `mod`(x, y: int): int {.magic: "ModI", noSideEffect, ...raises: [], tags: [],
                                 forbids: [].}

  Computes the integer modulo operation (remainder).

  This is the same as `x - (x div y) * y`.

  Example:

      assert (7 mod 5) == 2
      assert (-7 mod 5) == -2
      assert (7 mod -5) == 2
      assert (-7 mod -5) == -2

  Source Edit

    proc `mod`(x, y: int8): int8 {.magic: "ModI", noSideEffect, ...raises: [],
                                   tags: [], forbids: [].}

  Source Edit

    proc `mod`(x, y: int16): int16 {.magic: "ModI", noSideEffect, ...raises: [],
                                     tags: [], forbids: [].}

  Source Edit

    proc `mod`(x, y: int32): int32 {.magic: "ModI", noSideEffect, ...raises: [],
                                     tags: [], forbids: [].}

  Source Edit

    proc `mod`(x, y: int64): int64 {.magic: "ModI", noSideEffect, ...raises: [],
                                     tags: [], forbids: [].}

  Source Edit

    proc `mod`(x, y: uint): uint {.magic: "ModU", noSideEffect, ...raises: [],
                                   tags: [], forbids: [].}

  Computes the integer modulo operation (remainder) for unsigned integers. This is the same as `x - (x div y) * y`. Source Edit

    proc `mod`(x, y: uint8): uint8 {.magic: "ModU", noSideEffect, ...raises: [],
                                     tags: [], forbids: [].}

  Source Edit

    proc `mod`(x, y: uint16): uint16 {.magic: "ModU", noSideEffect, ...raises: [],
                                       tags: [], forbids: [].}

  Source Edit

    proc `mod`(x, y: uint32): uint32 {.magic: "ModU", noSideEffect, ...raises: [],
                                       tags: [], forbids: [].}

  Source Edit

    proc `mod`(x, y: uint64): uint64 {.magic: "ModU", noSideEffect, ...raises: [],
                                       tags: [], forbids: [].}

  Source Edit

    proc move[T](x: var T): T {.magic: "Move", noSideEffect, ...raises: [], tags: [],
                                forbids: [].}

  Source Edit

    proc moveMem(dest, source: pointer; size: Natural) {.inline, ...gcsafe, tags: [],
        raises: [], enforceNoRaises, ...forbids: [].}

  Copies the contents from the memory at `source` to the memory at `dest`.

  Exactly `size` bytes will be copied. The memory regions may overlap, `moveMem` handles this case appropriately and is thus somewhat more safe than `copyMem`. Like any procedure dealing with raw memory this is still unsafe, though.

  Source Edit

    proc new(t: typedesc): auto

  Creates a new object of type `T` and returns a safe (traced) reference to it as result value.

  When `T` is a ref type then the resulting type will be `T`, otherwise it will be `ref T`.

  Source Edit

    proc new[T](a: var ref T) {.magic: "New", noSideEffect, ...raises: [], tags: [],
                                forbids: [].}

  Creates a new object of type `T` and returns a safe (traced) reference to it in `a`. Source Edit

    proc new[T](a: var ref T; finalizer: proc (x: ref T) {.nimcall.}) {.
        magic: "NewFinalize", noSideEffect,
        ...deprecated: "pass a finalizer of the \'proc (x: T) {.nimcall.}\' type",
        raises: [], tags: [], forbids: [].}

  Deprecated: pass a finalizer of the 'proc (x: T) {.nimcall.}' type
  Source Edit

    proc new[T](a: var ref T; finalizer: proc (x: T) {.nimcall.}) {.
        magic: "NewFinalize", noSideEffect, ...raises: [], tags: [], forbids: [].}

  Creates a new object of type `T` and returns a safe (traced) reference to it in `a`.

  When the garbage collector frees the object, `finalizer` is called. The `finalizer` may not keep a reference to the object pointed to by `x`. The `finalizer` cannot prevent the GC from freeing the object.

  Note: The `finalizer` refers to the type `T`, not to the object! This means that for each object of type `T` the finalizer will be called!

  Source Edit

    proc newSeq[T](len = 0.Natural): seq[T]

  Creates a new sequence of type `seq[T]` with length `len`.

  Note that the sequence will be filled with zeroed entries. After the creation of the sequence you should assign entries to the sequence instead of adding them.

      var inputStrings = newSeq[string](3)
      assert len(inputStrings) == 3
      inputStrings[0] = "The fourth"
      inputStrings[1] = "assignment"
      inputStrings[2] = "would crash"
      #inputStrings[3] = "out of bounds"

  See also:

  - newSeqOfCap
  - newSeqUninit
  Source Edit

    proc newSeq[T](s: var seq[T]; len: Natural) {.magic: "NewSeq", noSideEffect,
        ...raises: [], tags: [], forbids: [].}

  Creates a new sequence of type `seq[T]` with length `len`.

  This is equivalent to `s = @[]; setlen(s, len)`, but more efficient since no reallocation is needed.

  Note that the sequence will be filled with zeroed entries. After the creation of the sequence you should assign entries to the sequence instead of adding them. Example:

      var inputStrings: seq[string]
      newSeq(inputStrings, 3)
      assert len(inputStrings) == 3
      inputStrings[0] = "The fourth"
      inputStrings[1] = "assignment"
      inputStrings[2] = "would crash"
      #inputStrings[3] = "out of bounds"

  Source Edit

    proc newSeqOfCap[T](cap: Natural): seq[T] {.magic: "NewSeqOfCap", noSideEffect,
        ...raises: [], tags: [], forbids: [].}

  Creates a new sequence of type `seq[T]` with length zero and capacity `cap`. Example:

      var x = newSeqOfCap[int](5)
      assert len(x) == 0
      x.add(10)
      assert len(x) == 1

  Source Edit

    func newSeqUninit[T](len: Natural): seq[T]

  Creates a new sequence of type `seq[T]` with length `len`.

  Only available for types, which don't contain managed memory or have destructors. Note that the sequence will be uninitialized. After the creation of the sequence you should assign entries to the sequence instead of adding them.

  Example:

      var x = newSeqUninit[int](3)
      assert len(x) == 3
      x[0] = 10

  Source Edit

    proc newSeqUninitialized[T: SomeNumber](len: Natural): seq[T] {.
        ...deprecated: "Use `newSeqUninit` instead".}

  Deprecated: Use `newSeqUninit` instead

  Creates a new sequence of type `seq[T]` with length `len`.

  Only available for numbers types. Note that the sequence will be uninitialized. After the creation of the sequence you should assign entries to the sequence instead of adding them. Example:

      var x = newSeqUninitialized[int](3)
      assert len(x) == 3
      x[0] = 10

  Source Edit

    proc newString(len: Natural): string {.magic: "NewString",
                                           importc: "mnewString", noSideEffect,
                                           ...raises: [], tags: [], forbids: [].}

  Returns a new string of length `len`. One needs to fill the string character after character with the index operator `s[i]`.

  This procedure exists only for optimization purposes; the same effect can be achieved with the `&` operator or with `add`.

  Source Edit

    proc newStringOfCap(cap: Natural): string {.magic: "NewStringOfCap",
        importc: "rawNewString", noSideEffect, ...raises: [], tags: [], forbids: [].}

  Returns a new string of length `0` but with capacity `cap`.

  This procedure exists only for optimization purposes; the same effect can be achieved with the `&` operator or with `add`.

  Source Edit

    proc newStringUninit(len: Natural): string {.noSideEffect, ...raises: [], tags: [],
        forbids: [].}

  Returns a new string of length `len` but with uninitialized content. One needs to fill the string character after character with the index operator `s[i]`.

  This procedure exists only for optimization purposes; the same effect can be achieved with the `&` operator or with `add`.

  Source Edit

    proc nimCStrLen(a: cstring): int {.compilerproc, nonReloadable, inline,
                                       enforceNoRaises, ...raises: [], tags: [],
                                       forbids: [].}

  Source Edit

    proc `not`(a: typedesc): typedesc {.magic: "TypeTrait", noSideEffect,
                                        ...raises: [], tags: [], forbids: [].}

  Constructs an `not` meta class. Source Edit

    proc `not`(x: bool): bool {.magic: "Not", noSideEffect, ...raises: [], tags: [],
                                forbids: [].}

  Boolean not; returns true if `x == false`. Source Edit

    proc `not`(x: int): int {.magic: "BitnotI", noSideEffect, ...raises: [], tags: [],
                              forbids: [].}

  Computes the `bitwise complement` of the integer `x`.

  Example:

      assert not 0'u8 == 255
      assert not 0'i8 == -1
      assert not 1000'u16 == 64535
      assert not 1000'i16 == -1001

  Source Edit

    proc `not`(x: int8): int8 {.magic: "BitnotI", noSideEffect, ...raises: [],
                                tags: [], forbids: [].}

  Source Edit

    proc `not`(x: int16): int16 {.magic: "BitnotI", noSideEffect, ...raises: [],
                                  tags: [], forbids: [].}

  Source Edit

    proc `not`(x: int32): int32 {.magic: "BitnotI", noSideEffect, ...raises: [],
                                  tags: [], forbids: [].}

  Source Edit

    proc `not`(x: int64): int64 {.magic: "BitnotI", noSideEffect, ...raises: [],
                                  tags: [], forbids: [].}

  Source Edit

    proc `not`(x: uint): uint {.magic: "BitnotI", noSideEffect, ...raises: [],
                                tags: [], forbids: [].}

  Computes the `bitwise complement` of the integer `x`. Source Edit

    proc `not`(x: uint8): uint8 {.magic: "BitnotI", noSideEffect, ...raises: [],
                                  tags: [], forbids: [].}

  Source Edit

    proc `not`(x: uint16): uint16 {.magic: "BitnotI", noSideEffect, ...raises: [],
                                    tags: [], forbids: [].}

  Source Edit

    proc `not`(x: uint32): uint32 {.magic: "BitnotI", noSideEffect, ...raises: [],
                                    tags: [], forbids: [].}

  Source Edit

    proc `not`(x: uint64): uint64 {.magic: "BitnotI", noSideEffect, ...raises: [],
                                    tags: [], forbids: [].}

  Source Edit

    proc `of`[T, S](x: T; y: typedesc[S]): bool {.magic: "Of", noSideEffect,
        ...raises: [], tags: [], forbids: [].}

  Checks if `x` is an instance of `y`.

  Example:

      type
        Base = ref object of RootObj
        Sub1 = ref object of Base
        Sub2 = ref object of Base
        Unrelated = ref object

      var base: Base = Sub1() # downcast
      doAssert base of Base # generates `CondTrue` (statically true)
      doAssert base of Sub1
      doAssert base isnot Sub1
      doAssert not (base of Sub2)

      base = Sub2() # re-assign
      doAssert base of Sub2
      doAssert Sub2(base) != nil # upcast
      doAssertRaises(ObjectConversionDefect): discard Sub1(base)

      var sub1 = Sub1()
      doAssert sub1 of Base
      doAssert sub1.Base of Sub1

      doAssert not compiles(base of Unrelated)

  Source Edit

    proc onThreadDestruction(handler: proc () {.closure, ...gcsafe, raises: [].}) {.
        ...raises: [], tags: [], forbids: [].}

  Registers a thread local handler that is called at the thread's destruction.

  A thread is destructed when the `.thread` proc returns normally or when it raises an exception. Note that unhandled exceptions in a thread nevertheless cause the whole process to die.

  Source Edit

    proc open[TMsg](c: var Channel[TMsg]; maxItems: int = 0) {....raises: [], gcsafe.}

  Opens a channel `c` for inter thread communication.

  The `send` operation will block until number of unprocessed items is less than `maxItems`.

  For unlimited queue set `maxItems` to 0.

  Source Edit

    proc `or`(a, b: typedesc): typedesc {.magic: "TypeTrait", noSideEffect,
                                          ...raises: [], tags: [], forbids: [].}

  Constructs an `or` meta class. Source Edit

    proc `or`(x, y: bool): bool {.magic: "Or", noSideEffect, ...raises: [], tags: [],
                                  forbids: [].}

  Boolean `or`; returns true if `not (not x and not y)` (if any of the arguments is true).

  Evaluation is lazy: if `x` is true, `y` will not even be evaluated.

  Source Edit

    proc `or`(x, y: int): int {.magic: "BitorI", noSideEffect, ...raises: [], tags: [],
                                forbids: [].}

  Computes the `bitwise or` of numbers `x` and `y`.

  Example:

      assert (0b0011 or 0b0101) == 0b0111
      assert (0b0111 or 0b1100) == 0b1111

  Source Edit

    proc `or`(x, y: int8): int8 {.magic: "BitorI", noSideEffect, ...raises: [],
                                  tags: [], forbids: [].}

  Source Edit

    proc `or`(x, y: int16): int16 {.magic: "BitorI", noSideEffect, ...raises: [],
                                    tags: [], forbids: [].}

  Source Edit

    proc `or`(x, y: int32): int32 {.magic: "BitorI", noSideEffect, ...raises: [],
                                    tags: [], forbids: [].}

  Source Edit

    proc `or`(x, y: int64): int64 {.magic: "BitorI", noSideEffect, ...raises: [],
                                    tags: [], forbids: [].}

  Source Edit

    proc `or`(x, y: uint): uint {.magic: "BitorI", noSideEffect, ...raises: [],
                                  tags: [], forbids: [].}

  Computes the `bitwise or` of numbers `x` and `y`. Source Edit

    proc `or`(x, y: uint8): uint8 {.magic: "BitorI", noSideEffect, ...raises: [],
                                    tags: [], forbids: [].}

  Source Edit

    proc `or`(x, y: uint16): uint16 {.magic: "BitorI", noSideEffect, ...raises: [],
                                      tags: [], forbids: [].}

  Source Edit

    proc `or`(x, y: uint32): uint32 {.magic: "BitorI", noSideEffect, ...raises: [],
                                      tags: [], forbids: [].}

  Source Edit

    proc `or`(x, y: uint64): uint64 {.magic: "BitorI", noSideEffect, ...raises: [],
                                      tags: [], forbids: [].}

  Source Edit

    func ord[T: Ordinal | enum](x: T): int {.magic: "Ord", ...raises: [], tags: [],
        forbids: [].}

  Returns the internal `int` value of `x`, including for enum with holes and distinct ordinal types.

  Example:

      assert ord('A') == 65
      type Foo = enum
        f0 = 0, f1 = 3
      assert f1.ord == 3
      type Bar = distinct int
      assert 3.Bar.ord == 3

  Source Edit

    proc peek[TMsg](c: var Channel[TMsg]): int {....raises: [], gcsafe.}

  Returns the current number of messages in the channel `c`.

  Returns -1 if the channel has been closed.

  Note: This is dangerous to use as it encourages races. It's much better to use tryRecv proc instead.

  Source Edit

    proc pop[T](s: var seq[T]): T {.inline, noSideEffect.}

  Returns the last item of `s` and decreases `s.len` by one. This treats `s` as a stack and implements the common pop operation.

  Raises `IndexDefect` if `s` is empty.

  Example:

      var a = @[1, 3, 5, 7]
      let b = pop(a)
      assert b == 7
      assert a == @[1, 3, 5]

  Source Edit

    proc pred[T: Ordinal; V: SomeInteger](x: T; y: V = 1): T {.magic: "Pred",
        noSideEffect, ...raises: [], tags: [], forbids: [].}

  Returns the `y`-th predecessor (default: 1) of the value `x`.

  If such a value does not exist, `OverflowDefect` is raised or a compile time error occurs.

  Example:

      assert pred(5) == 4
      assert pred(5, 3) == 2

  Source Edit

    proc prepareMutation(s: var string) {.inline, ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc procCall(x: untyped) {.magic: "ProcCall", compileTime, ...raises: [],
                                tags: [], forbids: [].}

  Special magic to prohibit dynamic binding for method calls. This is similar to super in ordinary OO languages.

      # 'someMethod' will be resolved fully statically:
      procCall someMethod(a, b)

  Source Edit

    proc protect(x: pointer): ForeignCell {....raises: [], tags: [], forbids: [].}

  Source Edit

    proc quit(errorcode: int = QuitSuccess) {.magic: "Exit", noreturn, ...raises: [],
        tags: [], forbids: [].}

  Stops the program immediately with an exit code.

  Before stopping the program the "exit procedures" are called in the opposite order they were added with addExitProc.

  The proc `quit(QuitSuccess)` is called implicitly when your nim program finishes without incident for platforms where this is the expected behavior. A raised unhandled exception is equivalent to calling `quit(QuitFailure)`.

  Note that this is a runtime call and using `quit` inside a macro won't have any compile time effect. If you need to stop the compiler inside a macro, use the error or fatal pragmas.

  Warning: `errorcode` gets saturated when it exceeds the valid range on the specific platform. On Posix, the valid range is `low(int8)..high(int8)`. On Windows, the valid range is `low(int32)..high(int32)`. For instance, `quit(int(0x100000000))` is equal to `quit(127)` on Linux.
  Danger: In almost all cases, in particular in library code, prefer alternatives, e.g. `raiseAssert` or raise a `Defect`. `quit` bypasses regular control flow in particular `defer`, `try`, `catch`, `finally` and `destructors`, and exceptions that may have been raised by an `addExitProc` proc, as well as cleanup code in other threads. It does not call the garbage collector to free all the memory, unless an `addExitProc` proc calls GC_fullCollect.
  Source Edit

    proc quit(errormsg: string; errorcode = QuitFailure) {.noreturn, ...raises: [],
        tags: [], forbids: [].}

  A shorthand for `echo(errormsg); quit(errorcode)`. Source Edit

    proc rawEnv[T: proc {.closure.} | iterator {.closure.}](x: T): pointer {.
        noSideEffect, inline.}

  Retrieves the raw environment pointer of the closure `x`. See also `rawProc`. This is not available for the JS target. Source Edit

    proc rawProc[T: proc {.closure.} | iterator {.closure.}](x: T): pointer {.
        noSideEffect, inline.}

  Retrieves the raw proc pointer of the closure `x`. This is useful for interfacing closures with C/C++, hash computations, etc. If `rawEnv(x)` returns `nil`, the proc which the result points to takes as many parameters as `x`, but with `{.nimcall.}` as its calling convention instead of `{.closure.}`, otherwise it takes one more parameter which is a `pointer`, and it still has `{.nimcall.}` as its calling convention. To invoke the resulted proc, what this returns has to be casted into a `proc`, not a `ptr proc`, and, in a case where `rawEnv(x)` returns non-`nil`, the last and additional argument has to be the result of `rawEnv(x)`. This is not available for the JS target.

  Example:

      proc makeClosure(x: int): (proc(y: int): int) =
        var n = x
        result = (
          proc(y: int): int =
            n += y
            return n
        )

      var
        c1 = makeClosure(10)
        e = c1.rawEnv()
        p = c1.rawProc()

      if e.isNil():
        let c2 = cast[proc(y: int): int {.nimcall.}](p)
        echo c2(2)
      else:
        let c3 = cast[proc(y: int; env: pointer): int {.nimcall.}](p)
        echo c3(3, e)

  Source Edit

    proc ready[TMsg](c: var Channel[TMsg]): bool {....raises: [], gcsafe.}

  Returns true if some thread is waiting on the channel `c` for new messages. Source Edit

    proc realloc0Impl(p: pointer; oldSize, newSize: Natural): pointer {.noconv,
        ...gcsafe, tags: [], gcsafe, raises: [], forbids: [].}

  Source Edit

    proc reallocImpl(p: pointer; newSize: Natural): pointer {.noconv, ...gcsafe,
        tags: [], gcsafe, raises: [], forbids: [].}

  Source Edit

    proc reallocShared0Impl(p: pointer; oldSize, newSize: Natural): pointer {.
        noconv, ...gcsafe, tags: [], gcsafe, raises: [], forbids: [].}

  Source Edit

    proc reallocSharedImpl(p: pointer; newSize: Natural): pointer {.noconv, ...gcsafe,
        tags: [], gcsafe, raises: [], forbids: [].}

  Source Edit

    proc recv[TMsg](c: var Channel[TMsg]): TMsg {....raises: [], gcsafe.}

  Receives a message from the channel `c`.

  This blocks until a message has arrived! You may use peek proc to avoid the blocking.

  Source Edit

    proc repr[T, U](x: HSlice[T, U]): string

  Generic `repr` operator for slices that is lifted from the components of `x`. Example:

      $(1 .. 5) == "1 .. 5"

  Source Edit

    proc reset[T](obj: var T) {.noSideEffect.}

  Resets an object `obj` to its default value. Source Edit

    proc resize[T](p: ptr T; newSize: Natural): ptr T {.inline, ...gcsafe, raises: [].}

  Grows or shrinks a given memory block.

  If `p` is nil then a new memory block is returned. In either way the block has at least `T.sizeof * newSize` bytes. If `newSize == 0` and `p` is not nil `resize` calls `dealloc(p)`. In other cases the block has to be freed with `free`.

  The allocated memory belongs to its allocating thread! Use resizeShared to reallocate from a shared heap.

  Source Edit

    proc resizeShared[T](p: ptr T; newSize: Natural): ptr T {.inline, ...raises: [].}

  Grows or shrinks a given memory block on the heap.

  If `p` is nil then a new memory block is returned. In either way the block has at least `T.sizeof * newSize` bytes. If `newSize == 0` and `p` is not nil `resizeShared` calls `freeShared(p)`. In other cases the block has to be freed with freeShared.

  Source Edit

    proc runnableExamples(rdoccmd = ""; body: untyped) {.magic: "RunnableExamples",
        ...raises: [], tags: [], forbids: [].}

  A section you should use to mark runnable example code with.
  - In normal debug and release builds code within a `runnableExamples` section is ignored.
  - The documentation generator is aware of these examples and considers them part of the `##` doc comment. As the last step of documentation generation each runnableExample is put in its own file `$file_examples$i.nim`, compiled and tested. The collected examples are put into their own module to ensure the examples do not refer to non-exported symbols.

  Example:

      proc timesTwo*(x: int): int =
        ## This proc doubles a number.
        runnableExamples:
          # at module scope
          const exported* = 123
          assert timesTwo(5) == 10
          block: # at block scope
            defer: echo "done"
        runnableExamples "-d:foo -b:cpp":
          import std/compilesettings
          assert querySetting(backend) == "cpp"
          assert defined(foo)
        runnableExamples "-r:off": ## this one is only compiled
           import std/browsers
           openDefaultBrowser "https://forum.nim-lang.org/"
        2 * x

  Source Edit

    proc send[TMsg](c: var Channel[TMsg]; msg: sink TMsg) {.inline, ...raises: [],
        gcsafe.}

  Sends a message to a thread. Source Edit

    proc setControlCHook(hook: proc () {.noconv.}) {....raises: [], gcsafe, tags: [],
        forbids: [].}

  Allows you to override the behaviour of your application when CTRL+C is pressed. Only one such hook is supported.

  The handler runs inside a C signal handler and comes with similar limitations.

  Allocating memory and interacting with most system calls, including using `echo`, `string`, `seq`, raising or catching exceptions etc is undefined behavior and will likely lead to application crashes.

  The OS may call the ctrl-c handler from any thread, including threads that were not created by Nim, such as happens on Windows.

  ## Example:

        var stop: Atomic[bool]
        proc ctrlc() {.noconv.} =
          # Using atomics types is safe!
          stop.store(true)

        setControlCHook(ctrlc)

        while not stop.load():
          echo "Still running.."
          sleep(1000)

  Source Edit

    proc setCurrentException(exc: ref Exception) {.inline, ...gcsafe, raises: [],
        tags: [], forbids: [].}

  Sets the current exception.
  Warning: Only use this if you know what you are doing.
  Source Edit

    proc setFrame(s: PFrame) {.compilerproc, inline, ...raises: [], tags: [],
                               forbids: [].}

  Source Edit

    proc setFrameState(state: FrameState) {.compilerproc, inline, ...raises: [],
                                            tags: [], forbids: [].}

  Source Edit

    proc setLen(s: var string; newlen: Natural) {.magic: "SetLengthStr",
        noSideEffect, ...raises: [], tags: [], forbids: [].}

  Sets the length of string `s` to `newlen`.

  If the current length is greater than the new length, `s` will be truncated.

      var myS = "Nim is great!!"
      myS.setLen(3) # myS <- "Nim"
      echo myS, " is fantastic!!"

  Source Edit

    proc setLen[T](s: var seq[T]; newlen: Natural) {.magic: "SetLengthSeq",
        noSideEffect, nodestroy, ...raises: [], tags: [], forbids: [].}

  Sets the length of seq `s` to `newlen`. `T` may be any sequence type.

  If the current length is greater than the new length, `s` will be truncated.

      var x = @[10, 20]
      x.setLen(5)
      x[4] = 50
      assert x == @[10, 20, 0, 0, 50]
      x.setLen(1)
      assert x == @[10]

  Source Edit

    func setLenUninit[T](s: var seq[T]; newlen: Natural) {.
        magic: "SetLengthSeqUninit", nodestroy, ...raises: [], tags: [], forbids: [].}

  Sets the length of seq `s` to `newlen`. `T` may be any sequence type. New slots will not be initialized.

  If the current length is greater than the new length, `s` will be truncated.

      var x = @[10, 20]
      x.setLenUninit(5)
      x[4] = 50
      assert x[4] == 50Add commentMore actions
      x.setLenUninit(1)
      assert x == @[10]

  Source Edit

    proc `shl`(x: int8; y: SomeInteger): int8 {.magic: "ShlI", noSideEffect,
        ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `shl`(x: int16; y: SomeInteger): int16 {.magic: "ShlI", noSideEffect,
        ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `shl`(x: int32; y: SomeInteger): int32 {.magic: "ShlI", noSideEffect,
        ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `shl`(x: int64; y: SomeInteger): int64 {.magic: "ShlI", noSideEffect,
        ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `shl`(x: int; y: SomeInteger): int {.magic: "ShlI", noSideEffect,
        ...raises: [], tags: [], forbids: [].}

  Computes the `shift left` operation of `x` and `y`. `y` (the number of positions to shift) is reduced to modulo `sizeof(x) * 8`. That is `15'i32 shl 35` is equivalent to `15'i32 shl 3`.

  Note: Operator precedence is different than in C.

  Example:

      assert 1'i32 shl 4 == 0x0000_0010
      assert 1'i64 shl 4 == 0x0000_0000_0000_0010

  Source Edit

    proc `shl`(x: uint8; y: SomeInteger): uint8 {.magic: "ShlI", noSideEffect,
        ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `shl`(x: uint16; y: SomeInteger): uint16 {.magic: "ShlI", noSideEffect,
        ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `shl`(x: uint32; y: SomeInteger): uint32 {.magic: "ShlI", noSideEffect,
        ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `shl`(x: uint64; y: SomeInteger): uint64 {.magic: "ShlI", noSideEffect,
        ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `shl`(x: uint; y: SomeInteger): uint {.magic: "ShlI", noSideEffect,
        ...raises: [], tags: [], forbids: [].}

  Computes the `shift left` operation of `x` and `y`. Source Edit

    proc `shr`(x: int8; y: SomeInteger): int8 {.magic: "AshrI", noSideEffect,
        ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `shr`(x: int16; y: SomeInteger): int16 {.magic: "AshrI", noSideEffect,
        ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `shr`(x: int32; y: SomeInteger): int32 {.magic: "AshrI", noSideEffect,
        ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `shr`(x: int64; y: SomeInteger): int64 {.magic: "AshrI", noSideEffect,
        ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `shr`(x: int; y: SomeInteger): int {.magic: "AshrI", noSideEffect,
        ...raises: [], tags: [], forbids: [].}

  Computes the `shift right` operation of `x` and `y`, filling vacant bit positions with the sign bit. `y` (the number of positions to shift) is reduced to modulo `sizeof(x) * 8`. That is `15'i32 shr 35` is equivalent to `15'i32 shr 3` bitmasked to always be in the range `0 ..< sizeof(int)`.

  Note: Operator precedence is different than in C.

  See also:

  - ashr func for arithmetic shift right

  Example:

      assert 0b0001_0000'i8 shr 2 == 0b0000_0100'i8
      assert 0b0000_0001'i8 shr 1 == 0b0000_0000'i8
      assert 0b1000_0000'i8 shr 4 == 0b1111_1000'i8
      assert -1 shr 5 == -1
      assert 1 shr 5 == 0
      assert 16 shr 2 == 4
      assert -16 shr 2 == -4

  Source Edit

    proc `shr`(x: uint8; y: SomeInteger): uint8 {.magic: "ShrI", noSideEffect,
        ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `shr`(x: uint16; y: SomeInteger): uint16 {.magic: "ShrI", noSideEffect,
        ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `shr`(x: uint32; y: SomeInteger): uint32 {.magic: "ShrI", noSideEffect,
        ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `shr`(x: uint64; y: SomeInteger): uint64 {.magic: "ShrI", noSideEffect,
        ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc `shr`(x: uint; y: SomeInteger): uint {.magic: "ShrI", noSideEffect,
        ...raises: [], tags: [], forbids: [].}

  Computes the `shift right` operation of `x` and `y`. Source Edit

    proc shrink[T](x: var seq[T]; newLen: Natural) {....tags: [], raises: [].}

  Source Edit

    proc sizeof(x: typedesc): int {.magic: "SizeOf", noSideEffect, ...raises: [],
                                    tags: [], forbids: [].}

  Source Edit

    proc sizeof[T](x: T): int {.magic: "SizeOf", noSideEffect, ...raises: [], tags: [],
                                forbids: [].}

  Returns the size of `x` in bytes.

  Since this is a low-level proc, its usage is discouraged - using new for the most cases suffices that one never needs to know `x`'s size.

  As a special semantic rule, `x` may also be a type identifier (`sizeof(int)` is valid).

  Limitations: If used for types that are imported from C or C++, sizeof should fallback to the `sizeof` in the C compiler. The result isn't available for the Nim compiler and therefore can't be used inside of macros.

      sizeof('A') # => 1
      sizeof(2) # => 8

  Source Edit

    proc slurp(filename: string): string {.magic: "Slurp", ...raises: [], tags: [],
                                           forbids: [].}

  This is an alias for staticRead. Source Edit

    proc stackTraceAvailable(): bool {....raises: [], tags: [], forbids: [].}

  Source Edit

    proc staticExec(command: string; input = ""; cache = ""): string {.
        magic: "StaticExec", ...raises: [], tags: [], forbids: [].}

  Executes an external process at compile-time and returns its text output (stdout + stderr).

  If `input` is not an empty string, it will be passed as a standard input to the executed program.

      const buildInfo = "Revision " & staticExec("git rev-parse HEAD") &
                        "\nCompiled on " & staticExec("uname -v")

  gorge is an alias for `staticExec`.

  Note that you can use this proc inside a pragma like passc or passl.

  If `cache` is not empty, the results of `staticExec` are cached within the `nimcache` directory. Use `--forceBuild` to get rid of this caching behaviour then. `command & input & cache` (the concatenated string) is used to determine whether the entry in the cache is still valid. You can use versioning information for `cache`:

      const stateMachine = staticExec("dfaoptimizer", "input", "0.8.0")

  Source Edit

    proc staticRead(filename: string): string {.magic: "Slurp", ...raises: [],
        tags: [], forbids: [].}

  Compile-time readFile proc for easy resource embedding:

  The maximum file size limit that `staticRead` and `slurp` can read is near or equal to the free memory of the device you are using to compile.

      const myResource = staticRead"mydatafile.bin"

  slurp is an alias for `staticRead`.

  Source Edit

    proc substr(a: openArray[char]): string {....raises: [], tags: [], forbids: [].}

  Returns a new string, copying contents of `a`.
  Warning: As opposed to other `substr` overloads, no additional input validation and clamping is performed!

  This proc does not prevent raising an `IndexDefect` when `a` is being passed using a `toOpenArray` call with out-of-bounds indexes:

  - `doAssertRaises(IndexDefect): discard "abc".toOpenArray(-9, 9).substr()`

  If clamping is required, consider using substr(s: string; first, last: int):

  - `doAssert "abc".substr(-9, 9) == "abc"`

  Example:

      let a = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h']
      assert a.substr() == "abcdefgh"
      assert a.toOpenArray(2, 5).substr() == "cdef"
      assert a.toOpenArray(2, high(a)).substr() == "cdefgh"  # From index 2 to `high(a)`
      doAssertRaises(IndexDefect): discard a.toOpenArray(5, 99).substr()

  Source Edit

    proc substr(s: string; first = 0): string {....raises: [], tags: [], forbids: [].}

  Convenience substr overload that returns a substring from `first` to the end of the string.

  `first` value is validated and capped:

  - `first >= s.len` returns an empty string
  - Negative `first` is clamped to 0.

  Example:

      let a = "abcdefgh"
      assert a.substr(2) == "cdefgh"    # From index 2 to string end (`high(a)`)
      assert a.substr(100) == ""        # `first` out of bounds
      assert a.substr(-1) == "abcdefgh" # Negative `first` clamped to 0

  Source Edit

    proc substr(s: string; first, last: int): string {....raises: [], tags: [],
        forbids: [].}

  Returns a new string containing a substring (slice) of `s`, copying characters from index `first` to index `last` inclusive.

  Index values are validated and capped:

  - Negative `first` is clamped to 0
  - If `last >= s.len`, it is clamped to `high(s)`
  - If `last < first`, returns an empty string

  This means `substr` can also be used to cut or limit a string's length.

  Note: If index values are ensured to be in-bounds, for performance critical cases consider using a non-clamping overload substr(a: openArray[char])

  Example:

      let a = "abcdefgh"
      assert a.substr(2, 5) == "cdef" # Normal substring
      # Invalid indexes
      assert a.substr(5, 99) == "fgh" # From index 5 to `high(a)`
      assert a.substr(42, 99) == ""   # `first` out of bounds
      assert a.substr(100, 5) == ""   # `first > last`
      assert a.substr(-1, 2) == "abc" # Negative `first` clamped to 0

  Source Edit

    proc succ[T: Ordinal; V: SomeInteger](x: T; y: V = 1): T {.magic: "Succ",
        noSideEffect, ...raises: [], tags: [], forbids: [].}

  Returns the `y`-th successor (default: 1) of the value `x`.

  If such a value does not exist, `OverflowDefect` is raised or a compile time error occurs.

  Example:

      assert succ(5) == 6
      assert succ(5, 3) == 8

  Source Edit

    proc swap[T](a, b: var T) {.magic: "Swap", noSideEffect, ...raises: [], tags: [],
                                forbids: [].}

  Swaps the values `a` and `b`.

  This is often more efficient than `tmp = a; a = b; b = tmp`. Particularly useful for sorting algorithms.

      var
        a = 5
        b = 9

      swap(a, b)

      assert a == 9
      assert b == 5

  Source Edit

    proc toBiggestFloat(i: BiggestInt): BiggestFloat {.noSideEffect, inline,
        ...raises: [], tags: [], forbids: [].}

  Same as toFloat but for `BiggestInt` to `BiggestFloat`. Source Edit

    proc toBiggestInt(f: BiggestFloat): BiggestInt {.noSideEffect, ...raises: [],
        tags: [], forbids: [].}

  Same as toInt but for `BiggestFloat` to `BiggestInt`. Source Edit

    proc toFloat(i: int): float {.noSideEffect, inline, ...raises: [], tags: [],
                                  forbids: [].}

  Converts an integer `i` into a `float`. Same as `float(i)`.

  If the conversion fails, `ValueError` is raised. However, on most platforms the conversion cannot fail.

      let
        a = 2
        b = 3.7

      echo a.toFloat + b # => 5.7

  Source Edit

    proc toInt(f: float): int {.noSideEffect, ...raises: [], tags: [], forbids: [].}

  Converts a floating point number `f` into an `int`.

  Conversion rounds `f` half away from 0, see Round half away from zero, as opposed to a type conversion which rounds towards zero.

  Note that some floating point numbers (e.g. infinity or even 1e19) cannot be accurately converted.

      doAssert toInt(0.49) == 0
      doAssert toInt(0.5) == 1
      doAssert toInt(-0.5) == -1 # rounding is symmetrical

  Source Edit

    proc toOpenArray(x: cstring; first, last: int): openArray[char] {.
        magic: "Slice", ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc toOpenArray(x: string; first, last: int): openArray[char] {.magic: "Slice",
        ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc toOpenArray[I, T](x: array[I, T]; first, last: I): openArray[T] {.
        magic: "Slice", ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc toOpenArray[T](x: openArray[T]; first, last: int): openArray[T] {.
        magic: "Slice", ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc toOpenArray[T](x: ptr UncheckedArray[T]; first, last: int): openArray[T] {.
        magic: "Slice", ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc toOpenArray[T](x: seq[T]; first, last: int): openArray[T] {.magic: "Slice",
        ...raises: [], tags: [], forbids: [].}

  Returns a non-owning slice (a view) of `x` from the element at index `first` to `last` inclusive. Allows passing slices without copying, as opposed to using the slice operator `[]`.

  Example:

      proc test(x: openArray[int]) =
        doAssert x == [1, 2, 3]

      let s = @[0, 1, 2, 3, 4]
      s.toOpenArray(1, 3).test

  Source Edit

    proc toOpenArrayByte(x: cstring; first, last: int): openArray[byte] {.
        magic: "Slice", ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc toOpenArrayByte(x: openArray[char]; first, last: int): openArray[byte] {.
        magic: "Slice", ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc toOpenArrayByte(x: seq[char]; first, last: int): openArray[byte] {.
        magic: "Slice", ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc toOpenArrayByte(x: string; first, last: int): openArray[byte] {.
        magic: "Slice", ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc toOpenArrayChar(x: openArray[byte]; first, last: int): openArray[char] {.
        magic: "Slice", ...raises: [], tags: [], forbids: [].}

  Source Edit

    proc tryRecv[TMsg](c: var Channel[TMsg]): tuple[dataAvailable: bool, msg: TMsg] {.
        ...raises: [], gcsafe.}

  Tries to receive a message from the channel `c`, but this can fail for all sort of reasons, including contention.

  If it fails, it returns `(false, default(msg))` otherwise it returns `(true, msg)`.

  Source Edit

    proc trySend[TMsg](c: var Channel[TMsg]; msg: sink TMsg): bool {.inline,
        ...raises: [], gcsafe.}

  Tries to send a message to a thread.

  Doesn't block.

  Returns `false` if the message was not sent because number of pending items in the channel exceeded `maxItems`.

  Source Edit

    proc typeof(x: untyped; mode = typeOfIter): typedesc {.magic: "TypeOf",
        noSideEffect, compileTime, ...raises: [], tags: [], forbids: [].}

  Builtin `typeof` operation for accessing the type of an expression. Since version 0.20.0.

  Example:

      proc myFoo(): float = 0.0
      iterator myFoo(): string = yield "abc"
      iterator myFoo2(): string = yield "abc"
      iterator myFoo3(): string {.closure.} = yield "abc"
      doAssert type(myFoo()) is string
      doAssert typeof(myFoo()) is string
      doAssert typeof(myFoo(), typeOfIter) is string
      doAssert typeof(myFoo3) is iterator

      doAssert typeof(myFoo(), typeOfProc) is float
      doAssert typeof(0.0, typeOfProc) is float
      doAssert typeof(myFoo3, typeOfProc) is iterator
      doAssert not compiles(typeof(myFoo2(), typeOfProc))
        # this would give: Error: attempting to call routine: 'myFoo2'
        # since `typeOfProc` expects a typed expression and `myFoo2()` can
        # only be used in a `for` context.

  Source Edit

    proc unsafeAddr[T](x: T): ptr T {.magic: "Addr", noSideEffect, ...raises: [],
                                      tags: [], forbids: [].}

  Warning: `unsafeAddr` is a deprecated alias for `addr`, use `addr` instead.
  Source Edit

    proc unsafeNew[T](a: var ref T; size: Natural) {.magic: "New", noSideEffect,
        ...raises: [], tags: [], forbids: [].}

  Creates a new object of type `T` and returns a safe (traced) reference to it in `a`.

  This is unsafe as it allocates an object of the passed `size`. This should only be used for optimization purposes when you know what you're doing!

  See also:

  - new
  Source Edit

    proc unsetControlCHook() {....raises: [], tags: [], forbids: [].}

  Reverts a call to setControlCHook. Source Edit

    proc wasMoved[T](obj: var T) {.magic: "WasMoved", noSideEffect, ...raises: [],
                                   tags: [], forbids: [].}

  Resets an object `obj` to its initial (binary zero) value to signify it was "moved" and to signify its destructor should do nothing and ideally be optimized away. Source Edit

    proc writeStackTrace() {....tags: [], gcsafe, raises: [], forbids: [].}

  Writes the current stack trace to `stderr`. This is only works for debug builds. Since it's usually used for debugging, this is proclaimed to have no IO effect! Source Edit

    proc `xor`(x, y: bool): bool {.magic: "Xor", noSideEffect, ...raises: [], tags: [],
                                   forbids: [].}

  Boolean `exclusive or`; returns true if `x != y` (if either argument is true while the other is false). Source Edit

    proc `xor`(x, y: int): int {.magic: "BitxorI", noSideEffect, ...raises: [],
                                 tags: [], forbids: [].}

  Computes the `bitwise xor` of numbers `x` and `y`.

  Example:

      assert (0b0011 xor 0b0101) == 0b0110
      assert (0b0111 xor 0b1100) == 0b1011

  Source Edit

    proc `xor`(x, y: int8): int8 {.magic: "BitxorI", noSideEffect, ...raises: [],
                                   tags: [], forbids: [].}

  Source Edit

    proc `xor`(x, y: int16): int16 {.magic: "BitxorI", noSideEffect, ...raises: [],
                                     tags: [], forbids: [].}

  Source Edit

    proc `xor`(x, y: int32): int32 {.magic: "BitxorI", noSideEffect, ...raises: [],
                                     tags: [], forbids: [].}

  Source Edit

    proc `xor`(x, y: int64): int64 {.magic: "BitxorI", noSideEffect, ...raises: [],
                                     tags: [], forbids: [].}

  Source Edit

    proc `xor`(x, y: uint): uint {.magic: "BitxorI", noSideEffect, ...raises: [],
                                   tags: [], forbids: [].}

  Computes the `bitwise xor` of numbers `x` and `y`. Source Edit

    proc `xor`(x, y: uint8): uint8 {.magic: "BitxorI", noSideEffect, ...raises: [],
                                     tags: [], forbids: [].}

  Source Edit

    proc `xor`(x, y: uint16): uint16 {.magic: "BitxorI", noSideEffect, ...raises: [],
                                       tags: [], forbids: [].}

  Source Edit

    proc `xor`(x, y: uint32): uint32 {.magic: "BitxorI", noSideEffect, ...raises: [],
                                       tags: [], forbids: [].}

  Source Edit

    proc `xor`(x, y: uint64): uint64 {.magic: "BitxorI", noSideEffect, ...raises: [],
                                       tags: [], forbids: [].}

  Source Edit

    func zeroDefault[T](_: typedesc[T]): T {.magic: "ZeroDefault", ...raises: [],
        tags: [], forbids: [].}

  Returns the binary zeros representation of the type `T`. It ignores default fields of an object.

  See also:

  - default
  Source Edit

    proc zeroMem(p: pointer; size: Natural) {.inline, noSideEffect, ...tags: [],
        raises: [], enforceNoRaises, ...forbids: [].}

  Overwrites the contents of the memory at `p` with the value 0.

  Exactly `size` bytes will be overwritten. Like any procedure dealing with raw memory this is unsafe.

  Source Edit

    proc `|`(a, b: typedesc): typedesc

  Source Edit

# Iterators

    iterator `..`(a, b: int32): int32 {.inline, ...raises: [], tags: [], forbids: [].}

  A type specialized version of `..` for convenience so that mixing integer types works better.

  See also:

  - ..<
  Source Edit

    iterator `..`(a, b: int64): int64 {.inline, ...raises: [], tags: [], forbids: [].}

  A type specialized version of `..` for convenience so that mixing integer types works better.

  See also:

  - ..<
  Source Edit

    iterator `..`(a, b: uint32): uint32 {.inline, ...raises: [], tags: [], forbids: [].}

  A type specialized version of `..` for convenience so that mixing integer types works better.

  See also:

  - ..<
  Source Edit

    iterator `..`(a, b: uint64): uint64 {.inline, ...raises: [], tags: [], forbids: [].}

  A type specialized version of `..` for convenience so that mixing integer types works better.

  See also:

  - ..<
  Source Edit

    iterator `..`[T](a, b: T): T {.inline.}

  An alias for `countup(a, b, 1)`.

  See also:

  - ..<

  Example:

      import std/sugar

      let x = collect(newSeq):
        for i in 3 .. 7:
          i

      assert x == @[3, 4, 5, 6, 7]

  Source Edit

    iterator `..<`(a, b: int32): int32 {.inline, ...raises: [], tags: [], forbids: [].}

  A type specialized version of `..<` for convenience so that mixing integer types works better. Source Edit

    iterator `..<`(a, b: int64): int64 {.inline, ...raises: [], tags: [], forbids: [].}

  A type specialized version of `..<` for convenience so that mixing integer types works better. Source Edit

    iterator `..<`(a, b: uint32): uint32 {.inline, ...raises: [], tags: [], forbids: [].}

  A type specialized version of `..<` for convenience so that mixing integer types works better. Source Edit

    iterator `..<`(a, b: uint64): uint64 {.inline, ...raises: [], tags: [], forbids: [].}

  A type specialized version of `..<` for convenience so that mixing integer types works better. Source Edit

    iterator `..<`[T](a, b: T): T {.inline.}

  Source Edit

    iterator countdown[T](a, b: T; step: Positive = 1): T {.inline.}

  Counts from ordinal value `a` down to `b` (inclusive) with the given step count.

  `T` may be any ordinal type, `step` may only be positive.

  Note: This fails to count to `low(int)` if T = int for efficiency reasons.

  Example:

      import std/sugar
      let x = collect(newSeq):
        for i in countdown(7, 3):
          i

      assert x == @[7, 6, 5, 4, 3]

      let y = collect(newseq):
        for i in countdown(9, 2, 3):
          i
      assert y == @[9, 6, 3]

  Source Edit

    iterator countup[T](a, b: T; step: Positive = 1): T {.inline.}

  Counts from ordinal value `a` to `b` (inclusive) with the given step count.

  `T` may be any ordinal type, `step` may only be positive.

  Note: This fails to count to `high(int)` if T = int for efficiency reasons.

  Example:

      import std/sugar
      let x = collect(newSeq):
        for i in countup(3, 7):
          i

      assert x == @[3, 4, 5, 6, 7]

      let y = collect(newseq):
        for i in countup(2, 9, 3):
          i
      assert y == @[2, 5, 8]

  Source Edit

    iterator `||`[S, T](a: S; b: T; annotation: static string = "parallel for"): T {.
        inline, magic: "OmpParFor", sideEffect, ...raises: [], tags: [], forbids: [].}

  OpenMP parallel loop iterator. Same as `..` but the loop may run in parallel.

  `annotation` is an additional annotation for the code generator to use. The default annotation is `parallel for`. Please refer to the OpenMP Syntax Reference for further information.

  Note that the compiler maps that to the `#pragma omp parallel for` construct of OpenMP and as such isn't aware of the parallelism in your code! Be careful! Later versions of `||` will get proper support by Nim's code generator and GC.

  Source Edit

    iterator `||`[S, T](a: S; b: T; step: Positive;
                        annotation: static string = "parallel for"): T {.inline,
        magic: "OmpParFor", sideEffect, ...raises: [], tags: [], forbids: [].}

  OpenMP parallel loop iterator with stepping. Same as `countup` but the loop may run in parallel.

  `annotation` is an additional annotation for the code generator to use. The default annotation is `parallel for`. Please refer to the OpenMP Syntax Reference for further information.

  Note that the compiler maps that to the `#pragma omp parallel for` construct of OpenMP and as such isn't aware of the parallelism in your code! Be careful! Later versions of `||` will get proper support by Nim's code generator and GC.

  Source Edit

# Macros

    macro varargsLen(x: varargs[untyped]): int

  returns number of variadic arguments in `x` Source Edit

# Templates

    template `!=`(x, y: untyped): untyped {.callsite.}

  Unequals operator. This is a shorthand for `not (x == y)`. Source Edit

    template `&=`(x, y: typed)

  Generic 'sink' operator for Nim.

  If not specialized further, an alias for `add`.

  Source Edit

    template `..<`(a, b: untyped): untyped

  A shortcut for `a .. pred(b)`.

      for i in 5 ..< 9:
        echo i # => 5; 6; 7; 8

  Source Edit

    template `..^`(a, b: untyped): untyped

  A shortcut for `.. ^` to avoid the common gotcha that a space between '..' and '^' is required. Source Edit

    template `=dispose`[T](x: owned(ref T)) {..}

  Source Edit

    template `>`(x, y: untyped): untyped {.callsite.}

  "is greater" operator. This is the same as `y < x`. Source Edit

    template `>%`(x, y: untyped): untyped

  Treats `x` and `y` as unsigned and compares them. Returns true if `unsigned(x) > unsigned(y)`. Source Edit

    template `>=`(x, y: untyped): untyped {.callsite.}

  "is greater or equals" operator. This is the same as `y <= x`. Source Edit

    template `>=%`(x, y: untyped): untyped

  Treats `x` and `y` as unsigned and compares them. Returns true if `unsigned(x) >= unsigned(y)`. Source Edit

    template `[]`(s: string; i: int): char

  Source Edit

    template `[]=`(s: string; i: int; val: char)

  Source Edit

    template `^`(x: int): BackwardsIndex

  Builtin roof operator that can be used for convenient array access. `a[^x]` is a shortcut for `a[a.len-x]`.

      let
        a = [1, 3, 5, 7, 9]
        b = "abcdefgh"

      echo a[^1] # => 9
      echo b[^2] # => g

  Source Edit

    template alloc(size: Natural): pointer

  Allocates a new memory block with at least `size` bytes.

  The block has to be freed with realloc(block, 0) or dealloc(block). The block is not initialized, so reading from it before writing to it is undefined behaviour!

  The allocated memory belongs to its allocating thread! Use allocShared to allocate from a shared heap.

  See also:

  - alloc0
  Source Edit

    template alloc0(size: Natural): pointer

  Allocates a new memory block with at least `size` bytes.

  The block has to be freed with realloc(block, 0) or dealloc(block). The block is initialized with all bytes containing zero, so it is somewhat safer than alloc.

  The allocated memory belongs to its allocating thread! Use allocShared0 to allocate from a shared heap.

  Source Edit

    template allocShared(size: Natural): pointer

  Allocates a new memory block on the shared heap with at least `size` bytes.

  The block has to be freed with reallocShared(block, 0) or deallocShared(block).

  The block is not initialized, so reading from it before writing to it is undefined behaviour!

  See also:

  - allocShared0.
  Source Edit

    template allocShared0(size: Natural): pointer

  Allocates a new memory block on the shared heap with at least `size` bytes.

  The block has to be freed with reallocShared(block, 0) or deallocShared(block).

  The block is initialized with all bytes containing zero, so it is somewhat safer than allocShared.

  Source Edit

    template closureScope(body: untyped): untyped

  Useful when creating a closure in a loop to capture local loop variables by their current iteration values.

  Note: This template may not work in some cases, use capture instead.

  Example:

      var myClosure : proc()
      # without closureScope:
      for i in 0 .. 5:
        let j = i
        if j == 3:
          myClosure = proc() = echo j
      myClosure() # outputs 5. `j` is changed after closure creation
      # with closureScope:
      for i in 0 .. 5:
        closureScope: # Everything in this scope is locked after closure creation
          let j = i
          if j == 3:
            myClosure = proc() = echo j
      myClosure() # outputs 3

  Source Edit

    template currentSourcePath(): string

  Returns the full file-system path of the current source.

  To get the directory containing the current source, use it with ospaths2.parentDir() as `currentSourcePath.parentDir()`.

  The path returned by this template is set at compile time.

  See the docstring of macros.getProjectPath() for an example to see the distinction between the `currentSourcePath()` and `getProjectPath()`.

  See also:

  - ospaths2.getCurrentDir() proc
  Source Edit

    template disarm(x: typed)

  Useful for `disarming` dangling pointers explicitly for `--newruntime`. Regardless of whether `--newruntime` is used or not this sets the pointer or callback `x` to `nil`. This is an experimental API! Source Edit

    template dumpAllocstats(code: untyped)

  Source Edit

    template excl[T](x: var set[T]; y: set[T]) {.callsite.}

  Excludes the set `y` from the set `x`.

  Example:

      var a = {1, 3, 5, 7}
      var b = {3, 4, 5}
      a.excl(b)
      assert a == {1, 7}

  Source Edit

    template formatErrorIndexBound[T](i, a, b: T): string

  Source Edit

    template formatErrorIndexBound[T](i, n: T): string

  Source Edit

    template formatFieldDefect(f, discVal): string

  Source Edit

    template `in`(x, y: untyped): untyped {.dirty, callsite.}

  Sugar for `contains`.

      assert(1 in (1..3) == true)
      assert(5 in (1..3) == false)

  Source Edit

    template incl[T](x: var set[T]; y: set[T]) {.callsite.}

  Includes the set `y` in the set `x`.

  Example:

      var a = {1, 3, 5, 7}
      var b = {4, 5, 6}
      a.incl(b)
      assert a == {1, 3, 4, 5, 6, 7}

  Source Edit

    template `isnot`(x, y: untyped): untyped {.callsite.}

  Negated version of is. Equivalent to `not(x is y)`.

      assert 42 isnot float
      assert @[1, 2] isnot enum

  Source Edit

    template likely(val: bool): bool

  Hints the optimizer that `val` is likely going to be true.

  You can use this template to decorate a branch condition. On certain platforms this can help the processor predict better which branch is going to be run. Example:

      for value in inputValues:
        if likely(value <= 100):
          process(value)
        else:
          echo "Value too big!"

  On backends without branch prediction (JS and the nimscript VM), this template will not affect code execution.

  Source Edit

    template newException(exceptn: typedesc; message: string;
                          parentException: ref Exception = nil): untyped

  Creates an exception object of type `exceptn` and sets its `msg` field to `message`. Returns the new exception object. Source Edit

    template nimThreadProcWrapperBody(closure: untyped): untyped

  Source Edit

    template `notin`(x, y: untyped): untyped {.dirty, callsite.}

  Sugar for `not contains`.

      assert(1 notin (1..3) == false)
      assert(5 notin (1..3) == true)

  Source Edit

    template offsetOf[T](t: typedesc[T]; member: untyped): int

  Source Edit

    template offsetOf[T](value: T; member: untyped): int

  Source Edit

    template once(body: untyped): untyped

  Executes a block of code only once (the first time the block is reached).

      proc draw(t: Triangle) =
        once:
          graphicsInit()
        line(t.p1, t.p2)
        line(t.p2, t.p3)
        line(t.p3, t.p1)

  Source Edit

    template rangeCheck(cond)

  Helper for performing user-defined range checks. Such checks will be performed only when the `rangechecks` compile-time option is enabled. Source Edit

    template realloc(p: pointer; newSize: Natural): pointer

  Grows or shrinks a given memory block.

  If `p` is nil then a new memory block is returned. In either way the block has at least `newSize` bytes. If `newSize == 0` and `p` is not nil `realloc` calls `dealloc(p)`. In other cases the block has to be freed with dealloc(block).

  The allocated memory belongs to its allocating thread! Use reallocShared to reallocate from a shared heap.

  Source Edit

    template realloc0(p: pointer; oldSize, newSize: Natural): pointer

  Grows or shrinks a given memory block.

  If `p` is nil then a new memory block is returned. In either way the block has at least `newSize` bytes. If `newSize == 0` and `p` is not nil `realloc` calls `dealloc(p)`. In other cases the block has to be freed with dealloc(block).

  The block is initialized with all bytes containing zero, so it is somewhat safer then realloc

  The allocated memory belongs to its allocating thread! Use reallocShared to reallocate from a shared heap.

  Source Edit

    template reallocShared(p: pointer; newSize: Natural): pointer

  Grows or shrinks a given memory block on the heap.

  If `p` is nil then a new memory block is returned. In either way the block has at least `newSize` bytes. If `newSize == 0` and `p` is not nil `reallocShared` calls `deallocShared(p)`. In other cases the block has to be freed with deallocShared.

  Source Edit

    template reallocShared0(p: pointer; oldSize, newSize: Natural): pointer

  Grows or shrinks a given memory block on the heap.

  When growing, the new bytes of the block is initialized with all bytes containing zero, so it is somewhat safer then reallocShared

  If `p` is nil then a new memory block is returned. In either way the block has at least `newSize` bytes. If `newSize == 0` and `p` is not nil `reallocShared` calls `deallocShared(p)`. In other cases the block has to be freed with deallocShared.

  Source Edit

    template setupForeignThreadGc() {..}

  With `--mm:arc` a nop. Source Edit

    template tearDownForeignThreadGc() {..}

  With `--mm:arc` a nop. Source Edit

    template unlikely(val: bool): bool

  Hints the optimizer that `val` is likely going to be false.

  You can use this proc to decorate a branch condition. On certain platforms this can help the processor predict better which branch is going to be run. Example:

      for value in inputValues:
        if unlikely(value > 100):
          echo "Value too big!"
        else:
          process(value)

  On backends without branch prediction (JS and the nimscript VM), this template will not affect code execution.

  Source Edit

    template unown(x: typed): untyped

  Source Edit

# Exports

ValueError, FloatingPointDefect, ExecIOEffect, AccessViolationError, ArithmeticError, DeadThreadError, FloatUnderflowDefect, FloatOverflowError, LibraryError, TimeEffect, NilAccessError, IndexDefect, IndexError, RangeError, ArithmeticDefect, FieldError, StackOverflowDefect, StackOverflowError, OverflowDefect, FloatDivByZeroError, RangeDefect, WriteIOEffect, ObjectAssignmentError, AccessViolationDefect, AssertionDefect, AssertionError, KeyError, FloatInexactDefect, OutOfMemDefect, IOError, ReraiseDefect, DivByZeroError, ObjectAssignmentDefect, OutOfMemError, ObjectConversionError, ReadIOEffect, FloatDivByZeroDefect, DeadThreadDefect, FieldDefect, ResourceExhaustedError, FloatingPointError, FloatOverflowDefect, IOEffect, NilAccessDefect, FloatInexactError, FloatUnderflowError, FloatInvalidOpError, FloatInvalidOpDefect, ObjectConversionDefect, ReraiseError, DivByZeroDefect, OverflowError, EOFError, OSError, cuint, cdouble, csize_t, BiggestFloat, PFloat64, cshort, cuchar, culonglong, clongdouble, PInt64, cstringArray, BiggestInt, ByteAddress, cchar, cschar, clonglong, PFloat32, clong, cfloat, cint, PInt32, cushort, BiggestUInt, culong, atomicAndFetch, atomicExchange, ATOMIC_ACQ_REL, cpuRelax, atomicFetchAnd, atomicXorFetch, atomicFetchOr, ATOMIC_CONSUME, atomicTestAndSet, atomicStoreN, atomicOrFetch, atomicLoad, ATOMIC_SEQ_CST, atomicCompareExchange, atomicAlwaysLockFree, atomicClear, atomicIsLockFree, atomicStore, AtomMemModel, atomicDec, ATOMIC_RELAXED, AtomType, atomicLoadN, atomicAddFetch, atomicFetchXor, ATOMIC_RELEASE, cas, ATOMIC_ACQUIRE, atomicFetchNand, atomicNandFetch, fence, atomicThreadFence, atomicFetchAdd, atomicSubFetch, atomicSignalFence, atomicInc, atomicFetchSub, atomicExchangeN, atomicCompareExchangeN, onFailedAssert, assert, doAssert, raiseAssert, failedAssertImpl, doAssertRaises, mitems, items, mpairs, mitems, mitems, mpairs, items, items, pairs, mpairs, mpairs, mitems, items, pairs, mitems, items, fields, items, pairs, items, pairs, pairs, fieldPairs, mpairs, fields, items, fieldPairs, items, $, $, $, $, $, $, $, $, $, $, $, $, $, $, $, $, $, $, $, $, $, $, $, addFloat, $, $, $, $, running, createThread, joinThreads, Thread, handle, pinToCpu, joinThread, createThread, addInt, addInt, addInt, repr, repr, repr, reprDiscriminant, repr, repr, repr, repr, repr, repr, repr, repr, repr, repr, repr, repr, repr, repr, repr, repr, repr, repr, repr, repr, repr, repr, repr, repr, repr, len, $, $, Utf16Char, []=, WideCStringObj, $, WideCString, $, newWideCString, newWideCString, newWideCString, newWideCString, len, [], toWideCString, stderr, File, writeChars, readBytes, write, FileMode, write, stdout, writeFile, write, stdmsg, readFile, FileSeekPos, writeLine, writeBuffer, readLine, readChars, reopen, write, readChar, getFileSize, endOfFile, write, getOsFileHandle, setInheritable, writeBytes, readLines, getFileHandle, write, getFilePos, stdin, setStdIoUnbuffered, readChars, open, open, write, readBuffer, lines, &=, readLine, write, close, flushFile, writeFile, readAll, FileHandle, open, lines, write, setFilePos, readLines