Fund Nim and help us develop it further!

Nim is simple..

# compute average line length
  sum = 0
  count = 0

for line in stdin.lines:
  sum += line.len
  count += 1

echo("Average line length: ",
  if count > 0: sum / count else: 0)

..and type safe...

# create and greet someone
type Person = object
  name: string
  age: int

proc greet(p: Person) =
  echo "Hi, I'm ",, "."
  echo "I am ", p.age, " years old."

let p = Person(name:"Jon", age:18)
p.greet() # or greet(p)

C FFI is easy in Nim..

# declare a C procedure..
proc unsafeScanf(f: File, s: cstring)
    importc: "fscanf",
    header: "<stdio.h>".}

# ..and use it...
var x: cint
stdin.unsafeScanf("%d", addr x)

Compile and run with:
    $ nim c -r example.nim

..and DSLs are too...

# a simple html server
  jester, asyncdispatch, htmlgen

  get "/":
    resp h1("Hello world")


View in browser at:

Welcome to Nim

Nim is a statically typed, imperative programming language that tries to give the programmer ultimate power without compromises on runtime efficiency. This means it focuses on compile-time mechanisms in all their various forms.

Beneath a nice infix/indentation based syntax with a powerful (AST based, hygienic) macro system lies a semantic model that supports a soft realtime GC on thread local heaps. Asynchronous message passing is used between threads, so no "stop the world" mechanism is necessary. An unsafe shared memory heap is also provided for the increased efficiency that results from that model.

Nim is efficient

  • Native code generation (currently via compilation to C), not dependent on a virtual machine: Nim produces small executables without dependencies for easy redistribution.
  • A fast non-tracing garbage collector that supports soft real-time systems (like games).
  • System programming features: Ability to manage your own memory and access the hardware directly. Pointers to garbage collected memory are distinguished from pointers to manually managed memory.
  • Zero-overhead iterators.
  • Cross-module inlining.
  • Dynamic method binding with inlining and without virtual method table.
  • Compile time evaluation of user-defined functions.
  • Whole program dead code elimination: Only used functions are included in the executable.
  • Value-based datatypes: For instance, objects and arrays can be allocated on the stack.

Nim is expressive

  • The Nim compiler and all of the standard libraries are implemented in Nim.
  • Built-in high level datatypes: strings, sets, sequences, etc.
  • Modern type system with local type inference, tuples, variants, generics, etc.
  • User-defineable operators; code with new operators is often easier to read than code which overloads built-in operators. For example, a =~ operator is defined in the re module.
  • Macros can modify the abstract syntax tree at compile time.

Nim is elegant

  • Macros can use the imperative paradigm to construct parse trees. Nim does not require a different coding style for meta programming.
  • Macros cannot change Nim's syntax because there is no need for it. Nim's syntax is flexible enough.
  • Statements are grouped by indentation but can span multiple lines. Indentation must not contain tabulators so the compiler always sees the code the same way as you do.

Nim plays nice with others

  • The Nim Compiler runs on Windows, Linux, BSD and Mac OS X. Porting to other platforms is easy.
  • The Nim Compiler can also generate C++ or Objective C for easier interfacing.
  • There are lots of bindings: for example, bindings to GTK2, the Windows API, the POSIX API, OpenGL, SDL, Cairo, Python, Lua, TCL, X11, libzip, PCRE, libcurl, mySQL and SQLite are included in the standard distribution or can easily be obtained via the Nimble package manager.
  • A C to Nim conversion utility: New bindings to C libraries are easily generated by c2nim.

Roadmap to 1.0

Please have a look at this wiki page for an up-to-date overview.