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https://github.com/nim-lang/Nim.git
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e8d0f1c3ae
* fixes #16331; aliasing of tuple construction within a single assignment, great coding style * added test case
36 lines
731 B
Nim
36 lines
731 B
Nim
discard """
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targets: "c cpp"
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matrix: "--gc:refc; --gc:arc"
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"""
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# bug #1833
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iterator myitems*[T](a: var seq[T]): var T {.inline.} =
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## iterates over each item of `a` so that you can modify the yielded value.
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var i = 0
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let L = len(a)
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while i < L:
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yield a[i]
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inc(i)
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doAssert(len(a) == L, "the length of the seq changed while iterating over it")
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# Works fine
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var xs = @[1,2,3]
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for x in myitems(xs):
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inc x
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# Tuples don't work
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var ys = @[(1,"a"),(2,"b"),(3,"c")]
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for y in myitems(ys):
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inc y[0]
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# bug #16331
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type T1 = tuple[a, b: int]
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proc p(b: bool): string =
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var x: T1 = (10, 20)
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x = if b: (x.b, x.a) else: (-x.b, -x.a)
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$x
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assert p(false) == "(a: -20, b: -10)"
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assert p(true) == "(a: 20, b: 10)"
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