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This module provides basic primitives for creating parallel programs. A Task should be only owned by a single Thread, it cannot be shared by threads.

Example:

import std/tasks
block:
  var num = 0
  proc hello(a: int) = inc num, a

  let b = toTask hello(13)
  b.invoke()
  assert num == 13
  # A task can be invoked multiple times
  b.invoke()
  assert num == 26

block:
  type
    Runnable = ref object
      data: int

  var data: int
  proc hello(a: Runnable) {.nimcall.} =
    a.data += 2
    data = a.data


  when false:
    # the parameters of call must be isolated.
    let x = Runnable(data: 12)
    let b = toTask hello(x) # error ----> expression cannot be isolated: x
    b.invoke()

  let b = toTask(hello(Runnable(data: 12)))
  b.invoke()
  assert data == 14
  b.invoke()
  assert data == 16

Imports

macros, isolation, typetraits, assertions, effecttraits

Types

Task = object: Task contains the callback and its arguments. Source Edit

Procs

proc `=copy`(x: var Task; y: Task) {.error.}: Source Edit
proc `=destroy`(t: Task) {.inline, ...gcsafe, raises: [], tags: [RootEffect], forbids: [].}: Frees the resources allocated for a Task. Source Edit
proc invoke(task: Task; res: pointer = nil) {.inline, ...gcsafe, raises: [Exception], tags: [RootEffect], forbids: [].}: Invokes the task. Source Edit

Macros

macro toTask(e: typed{nkCall | nkInfix | nkPrefix | nkPostfix | nkCommand | nkCallStrLit}): Task: Converts the call and its arguments to Task.
Example:

proc hello(a: int) = echo a let b = toTask hello(13) assert b is Task
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