# std/setutils

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This module adds functionality for the built-in `set` type.

# See also

- std/packedsets
- std/sets

# Imports

typetraits, macros

# Procs

    proc `-+-`[T](x, y: set[T]): set[T] {.inline.}

  Operator alias for `symmetricDifference`.

  Example:

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

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    func `[]=`[T](t: var set[T]; key: T; val: bool) {.inline.}

  Syntax sugar for `if val: t.incl key else: t.excl key`

  Example:

      type A = enum
        a0, a1, a2, a3
      var s = {a0, a3}
      s[a0] = false
      s[a1] = false
      assert s == {a3}
      s[a2] = true
      s[a3] = true
      assert s == {a2, a3}

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    func complement[T](s: set[T]): set[T] {.inline.}

  Returns the set complement of `a`.

  Example:

      type Colors = enum
        red, green = 3, blue
      assert complement({red, blue}) == {green}
      assert complement({red, green, blue}).card == 0
      assert complement({range[0..10](0), 1, 2, 3}) == {range[0..10](4), 5, 6, 7, 8, 9, 10}
      assert complement({'0'..'9'}) == {0.char..255.char} - {'0'..'9'}

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    func fullSet[T](U: typedesc[T]): set[T] {.inline.}

  Returns a set containing all elements in `U`.

  Example:

      assert bool.fullSet == {true, false}
      type A = range[1..3]
      assert A.fullSet == {1.A, 2, 3}
      assert int8.fullSet.len == 256

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    func symmetricDifference[T](x, y: set[T]): set[T] {.magic: "XorSet", ...raises: [],
        tags: [], forbids: [].}

  This operator computes the symmetric difference of two sets, equivalent to but more efficient than `x + y - x * y` or `(x - y) + (y - x)`.

  Example:

      assert symmetricDifference({1, 2, 3}, {2, 3, 4}) == {1, 4}

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    proc toggle[T](x: var set[T]; y: set[T]) {.inline.}

  Toggles the existence of each value of `y` in `x`. If any element in `y` is also in `x`, it is excluded from `x`; otherwise it is included. Equivalent to `x = symmetricDifference(x, y)`.

  Example:

      var x = {1, 2, 3}
      x.toggle({2, 3, 4})
      assert x == {1, 4}

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# Templates

    template toSet(iter: untyped): untyped

  Returns a built-in set from the elements of the iterable `iter`.

  Example:

      assert "helloWorld".toSet == {'W', 'd', 'e', 'h', 'l', 'o', 'r'}
      assert toSet([10u16, 20, 30]) == {10u16, 20, 30}
      assert [30u8, 100, 10].toSet == {10u8, 30, 100}
      assert toSet(@[1321i16, 321, 90]) == {90i16, 321, 1321}
      assert toSet([false]) == {false}
      assert toSet(0u8..10) == {0u8..10}

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