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| author | Timothee Cour <timothee.cour2@gmail.com> | 2018-08-16 14:19:36 -0700 |
|---|---|---|
| committer | Andreas Rumpf <rumpf_a@web.de> | 2018-08-16 23:19:36 +0200 |
| commit | af037546b0b8fb77a9bd33c6f75f6c7c216fa9bb (patch) | |
| tree | fed4c8f29e51af1b491ba72b6d276493be13e39d /lib/pure/collections/sequtils.nim | |
| parent | 3ca8ebe778cb82cdbd97d7a9a00015bbeed1a696 (diff) | |
| download | Nim-af037546b0b8fb77a9bd33c6f75f6c7c216fa9bb.tar.gz | |
fixes #7187 sequtils.toSeq produces the sequence from the iterator twice (#8586)
* cleanups refs #8584 * fixes #7187
Diffstat (limited to 'lib/pure/collections/sequtils.nim')
| -rw-r--r-- | lib/pure/collections/sequtils.nim | 40 |
1 files changed, 26 insertions, 14 deletions
diff --git a/lib/pure/collections/sequtils.nim b/lib/pure/collections/sequtils.nim index c8080546a..612624f1d 100644 --- a/lib/pure/collections/sequtils.nim +++ b/lib/pure/collections/sequtils.nim @@ -518,13 +518,17 @@ template toSeq*(iter: untyped): untyped = ## result = true) ## assert odd_numbers == @[1, 3, 5, 7, 9] + # Note: see also `mapIt` for explanation of some of the implementation + # subtleties. when compiles(iter.len): - var i = 0 - var result = newSeq[type(iter)](iter.len) - for x in iter: - result[i] = x - inc i - result + block: + evalOnceAs(iter2, iter, true) + var result = newSeq[type(iter)](iter2.len) + var i = 0 + for x in iter2: + result[i] = x + inc i + result else: var result: seq[type(iter)] = @[] for x in iter: @@ -1031,6 +1035,12 @@ when isMainModule: result = true) assert odd_numbers == @[1, 3, 5, 7, 9] + block: + # tests https://github.com/nim-lang/Nim/issues/7187 + counter = 0 + let ret = toSeq(@[1, 2, 3].identity().filter(proc (x: int): bool = x < 3)) + doAssert ret == @[1, 2] + doAssert counter == 1 block: # foldl tests let numbers = @[5, 9, 11] @@ -1092,12 +1102,18 @@ when isMainModule: doAssert foo1(openArray[int]([identity(1),identity(2)])) == @[10,20] doAssert counter == 2 + # Corner cases (openArray litterals should not be common) template foo2(x: openArray[int]): seq[int] = x.mapIt(it * 10) counter = 0 doAssert foo2(openArray[int]([identity(1),identity(2)])) == @[10,20] # TODO: this fails; not sure how to fix this case # doAssert counter == 2 + counter = 0 + doAssert openArray[int]([identity(1), identity(2)]).mapIt(it) == @[1,2] + # ditto + # doAssert counter == 2 + block: # mapIt empty test, see https://github.com/nim-lang/Nim/pull/8584#pullrequestreview-144723468 # NOTE: `[].mapIt(it)` is illegal, just as `let a = @[]` is (lacks type # of elements) @@ -1106,16 +1122,12 @@ when isMainModule: doAssert newSeq[int](0).mapIt(it) == @[] block: # mapIt redifinition check, see https://github.com/nim-lang/Nim/issues/8580 - let t = [1,2].mapIt(it) - doAssert t == @[1,2] + let s2 = [1,2].mapIt(it) + doAssert s2 == @[1,2] block: - var counter = 0 - proc getInput():auto = - counter.inc - [1, 2] - doAssert getInput().mapIt(it*2).mapIt(it*10) == @[20, 40] - # make sure argument evaluated only once, analog to + counter = 0 + doAssert [1,2].identity().mapIt(it*2).mapIt(it*10) == @[20, 40] # https://github.com/nim-lang/Nim/issues/7187 test case doAssert counter == 1 |