This Month with Nim: September 2022

05 October 2022 The Nim Community

Node

Author: Juan Carlos

New APIs for the browser implemented recently

Nodejs is your toolbox with 70+ modules for JavaScript, Node, browser and more!

https://github.com/juancarlospaco/nodejs

QWatcher

Author: Pouriya Jamshidi

qwatcher is designed to help monitor TCP connections and diagnose buffer and connectivity issues on Linux machines related to input and output queues.

nim-sos

Author: Christopher Taylor

nim-sos provides users the ability to program parallel applications. In the Single-Program-Many-Data (SPMD) style for supercomputers using the Nim programming language.

nim-sos:

wraps the existing Sandia OpenSHMEM library implemented by Sandia National Laboratory.
implements distributed symmetric array and distributed symmetric scalar support using the underlying OpenSHMEM wrapper.
provides the Nim programming language distributed symmetric shared memory and Partitioned Global Address Space (PGAS) support.

assigns is a library for unpacking assignment and basic pattern matching. Its advantage over other libraries with the same goal is that it has a simple, lightweight implementation that allows for overloading matching syntaxes based on the type of the matched value.

import assigns

# unpacking assignment:
type Person = tuple[name: string, age: int]
(age: a, name: n) := ("John Smith", 30).Person
assert (a, n) == (30, "John Smith")

# pattern matching:
proc fizzbuzz(n: int): string =
  match (n mod 3, n mod 5):
  of (0, 0): "FizzBuzz"
  of (0, _): "Fizz"
  of (_, 0): "Buzz"
  else: $n

for i in 1..100:
  echo fizzbuzz(i)

# custom implementation:
import assigns/impl, std/macros

type LinkedList[T] {.acyclic.} = ref object
  leaf: T
  next: LinkedList[T]

implementAssign LinkedList: # sugar for defining the overloading macro
  # skip bracket:
  let newLhs = if lhs.kind == nnkBracket and lhs.len == 1: lhs[0] else: lhs
  # check for | operator:
  if newLhs.kind == nnkInfix and newLhs[0].eqIdent"|":
    # overloadably assign both parts
    newStmtList(
      open(newLhs[1], newDotExpr(rhs, ident"leaf")),
      open(newLhs[2], newDotExpr(rhs, ident"next")))
  else:
    # use default assignment syntax if expression is not understood
    default()

let list = LinkedList[int](leaf: 1, next:
  LinkedList[int](leaf: 2, next:
    LinkedList[int](leaf: 3, next: nil)))

x | [(< 5) | [y | _]] := list
assert (x, y) == (1, 3)

Can be installed with nimble install assigns. More information in docs.

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