iterators

Iterators

iterator items[T: not char](a: openArray[T]): lent2 T {...}{.inline.}
Iterates over each item of a. Source Edit
iterator items[T: char](a: openArray[T]): T {...}{.inline.}
Iterates over each item of a. Source Edit
iterator mitems[T](a: var openArray[T]): var T {...}{.inline.}
Iterates over each item of a so that you can modify the yielded value. Source Edit
iterator items[IX, T](a: array[IX, T]): T {...}{.inline.}
Iterates over each item of a. Source Edit
iterator mitems[IX, T](a: var array[IX, T]): var T {...}{.inline.}
Iterates over each item of a so that you can modify the yielded value. Source Edit
iterator items[T](a: set[T]): T {...}{.inline.}
Iterates over each element of a. items iterates only over the elements that are really in the set (and not over the ones the set is able to hold). Source Edit
iterator items(a: cstring): char {...}{.inline, raises: [], tags: [].}
Iterates over each item of a. Source Edit
iterator mitems(a: var cstring): var char {...}{.inline, raises: [], tags: [].}
Iterates over each item of a so that you can modify the yielded value. Source Edit
iterator items(E: typedesc[enum]): E:type
Iterates over the values of the enum E. Source Edit
iterator items[T](s: HSlice[T, T]): T
Iterates over the slice s, yielding each value between s.a and s.b (inclusively). Source Edit
iterator pairs[T](a: openArray[T]): tuple[key: int, val: T] {...}{.inline.}
Iterates over each item of a. Yields (index, a[index]) pairs. Source Edit
iterator mpairs[T](a: var openArray[T]): tuple[key: int, val: var T] {...}{.inline.}
Iterates over each item of a. Yields (index, a[index]) pairs. a[index] can be modified. Source Edit
iterator pairs[IX, T](a: array[IX, T]): tuple[key: IX, val: T] {...}{.inline.}
Iterates over each item of a. Yields (index, a[index]) pairs. Source Edit
iterator mpairs[IX, T](a: var array[IX, T]): tuple[key: IX, val: var T] {...}{.inline.}
Iterates over each item of a. Yields (index, a[index]) pairs. a[index] can be modified. Source Edit
iterator pairs[T](a: seq[T]): tuple[key: int, val: T] {...}{.inline.}
Iterates over each item of a. Yields (index, a[index]) pairs. Source Edit
iterator mpairs[T](a: var seq[T]): tuple[key: int, val: var T] {...}{.inline.}
Iterates over each item of a. Yields (index, a[index]) pairs. a[index] can be modified. Source Edit
iterator pairs(a: string): tuple[key: int, val: char] {...}{.inline, raises: [],
    tags: [].}
Iterates over each item of a. Yields (index, a[index]) pairs. Source Edit
iterator mpairs(a: var string): tuple[key: int, val: var char] {...}{.inline,
    raises: [], tags: [].}
Iterates over each item of a. Yields (index, a[index]) pairs. a[index] can be modified. Source Edit
iterator pairs(a: cstring): tuple[key: int, val: char] {...}{.inline, raises: [],
    tags: [].}
Iterates over each item of a. Yields (index, a[index]) pairs. Source Edit
iterator mpairs(a: var cstring): tuple[key: int, val: var char] {...}{.inline,
    raises: [], tags: [].}
Iterates over each item of a. Yields (index, a[index]) pairs. a[index] can be modified. Source Edit
iterator items[T](a: seq[T]): lent2 T {...}{.inline.}
Iterates over each item of a. Source Edit
iterator mitems[T](a: var seq[T]): var T {...}{.inline.}
Iterates over each item of a so that you can modify the yielded value. Source Edit
iterator items(a: string): char {...}{.inline, raises: [], tags: [].}
Iterates over each item of a. Source Edit
iterator mitems(a: var string): var char {...}{.inline, raises: [], tags: [].}
Iterates over each item of a so that you can modify the yielded value. Source Edit
iterator fields[T: tuple | object](x: T): RootObj {...}{.magic: "Fields",
    noSideEffect.}

Iterates over every field of x.

Warning: This really transforms the 'for' and unrolls the loop. The current implementation also has a bug that affects symbol binding in the loop body.

Example:

var t = (1, "foo")
for v in fields(t): v = default(type(v))
doAssert t == (0, "")
Source Edit
iterator fields[S: tuple | object; T: tuple | object](x: S; y: T): tuple[
    key: string, val: RootObj] {...}{.magic: "Fields", noSideEffect.}

Iterates over every field of x and y.

Warning: This really transforms the 'for' and unrolls the loop. The current implementation also has a bug that affects symbol binding in the loop body.

Example:

var t1 = (1, "foo")
var t2 = default(type(t1))
for v1, v2 in fields(t1, t2): v2 = v1
doAssert t1 == t2
Source Edit
iterator fieldPairs[T: tuple | object](x: T): tuple[key: string, val: RootObj] {...}{.
    magic: "FieldPairs", noSideEffect.}

Iterates over every field of x returning their name and value.

When you iterate over objects with different field types you have to use the compile time when instead of a runtime if to select the code you want to run for each type. To perform the comparison use the is operator. Another way to do the same without when is to leave the task of picking the appropriate code to a secondary proc which you overload for each field type and pass the value to.

Warning: This really transforms the 'for' and unrolls the loop. The current implementation also has a bug that affects symbol binding in the loop body.

Example:

type
  Custom = object
    foo: string
    bar: bool
proc `$`(x: Custom): string =
  result = "Custom:"
  for name, value in x.fieldPairs:
    when value is bool:
      result.add("\n\t" & name & " is " & $value)
    else:
      result.add("\n\t" & name & " '" & value & "'")
Source Edit
iterator fieldPairs[S: tuple | object; T: tuple | object](x: S; y: T): tuple[
    key: string, a, b: RootObj] {...}{.magic: "FieldPairs", noSideEffect.}

Iterates over every field of x and y.

Warning: This really transforms the 'for' and unrolls the loop. The current implementation also has a bug that affects symbol binding in the loop body.

Example:

type Foo = object
  x1: int
  x2: string
var a1 = Foo(x1: 12, x2: "abc")
var a2: Foo
for name, v1, v2 in fieldPairs(a1, a2):
  when name == "x2": v2 = v1
doAssert a2 == Foo(x1: 0, x2: "abc")
Source Edit

© 2006–2021 Andreas Rumpf
Licensed under the MIT License.
https://nim-lang.org/docs/iterators.html