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Diffstat (limited to 'lib/system/iterators_1.nim')
| -rw-r--r-- | lib/system/iterators_1.nim | 180 |
1 files changed, 180 insertions, 0 deletions
diff --git a/lib/system/iterators_1.nim b/lib/system/iterators_1.nim new file mode 100644 index 000000000..d00e3f823 --- /dev/null +++ b/lib/system/iterators_1.nim @@ -0,0 +1,180 @@ +when sizeof(int) <= 2: + type IntLikeForCount = int|int8|int16|char|bool|uint8|enum +else: + type IntLikeForCount = int|int8|int16|int32|char|bool|uint8|uint16|enum + +iterator countdown*[T](a, b: T, step: Positive = 1): T {.inline.} = + ## Counts from ordinal value `a` down to `b` (inclusive) with the given + ## step count. + ## + ## `T` may be any ordinal type, `step` may only be positive. + ## + ## **Note**: This fails to count to `low(int)` if T = int for + ## efficiency reasons. + runnableExamples: + import std/sugar + let x = collect(newSeq): + for i in countdown(7, 3): + i + + assert x == @[7, 6, 5, 4, 3] + + let y = collect(newseq): + for i in countdown(9, 2, 3): + i + assert y == @[9, 6, 3] + when T is (uint|uint64): + var res = a + while res >= b: + yield res + if res == b: break + dec(res, step) + elif T is IntLikeForCount and T is Ordinal: + var res = int(a) + while res >= int(b): + when defined(nimHasCastExtendedVm): + yield cast[T](res) + else: + yield T(res) + dec(res, step) + else: + var res = a + while res >= b: + yield res + dec(res, step) + +iterator countup*[T](a, b: T, step: Positive = 1): T {.inline.} = + ## Counts from ordinal value `a` to `b` (inclusive) with the given + ## step count. + ## + ## `T` may be any ordinal type, `step` may only be positive. + ## + ## **Note**: This fails to count to `high(int)` if T = int for + ## efficiency reasons. + runnableExamples: + import std/sugar + let x = collect(newSeq): + for i in countup(3, 7): + i + + assert x == @[3, 4, 5, 6, 7] + + let y = collect(newseq): + for i in countup(2, 9, 3): + i + assert y == @[2, 5, 8] + mixin inc + when T is IntLikeForCount and T is Ordinal: + var res = int(a) + while res <= int(b): + when defined(nimHasCastExtendedVm): + yield cast[T](res) + else: + yield T(res) + inc(res, step) + else: + var res = a + while res <= b: + yield res + inc(res, step) + +iterator `..`*[T](a, b: T): T {.inline.} = + ## An alias for `countup(a, b, 1)`. + ## + ## See also: + ## * [..<](#..<.i,T,T) + runnableExamples: + import std/sugar + + let x = collect(newSeq): + for i in 3 .. 7: + i + + assert x == @[3, 4, 5, 6, 7] + mixin inc + when T is IntLikeForCount and T is Ordinal: + var res = int(a) + while res <= int(b): + when defined(nimHasCastExtendedVm): + yield cast[T](res) + else: + yield T(res) + inc(res) + else: + var res = a + while res <= b: + yield res + inc(res) + +template dotdotImpl(t) {.dirty.} = + iterator `..`*(a, b: t): t {.inline.} = + ## A type specialized version of `..` for convenience so that + ## mixing integer types works better. + ## + ## See also: + ## * [..<](#..<.i,T,T) + var res = a + while res <= b: + yield res + inc(res) + +dotdotImpl(int64) +dotdotImpl(int32) +dotdotImpl(uint64) +dotdotImpl(uint32) + +iterator `..<`*[T](a, b: T): T {.inline.} = + mixin inc + var i = a + while i < b: + yield i + inc i + +template dotdotLessImpl(t) {.dirty.} = + iterator `..<`*(a, b: t): t {.inline.} = + ## A type specialized version of `..<` for convenience so that + ## mixing integer types works better. + var res = a + while res < b: + yield res + inc(res) + +dotdotLessImpl(int64) +dotdotLessImpl(int32) +dotdotLessImpl(uint64) +dotdotLessImpl(uint32) + +iterator `||`*[S, T](a: S, b: T, annotation: static string = "parallel for"): T {. + inline, magic: "OmpParFor", sideEffect.} = + ## OpenMP parallel loop iterator. Same as `..` but the loop may run in parallel. + ## + ## `annotation` is an additional annotation for the code generator to use. + ## The default annotation is `parallel for`. + ## Please refer to the `OpenMP Syntax Reference + ## <https://www.openmp.org/wp-content/uploads/OpenMP-4.5-1115-CPP-web.pdf>`_ + ## for further information. + ## + ## Note that the compiler maps that to + ## the `#pragma omp parallel for` construct of `OpenMP`:idx: and as + ## such isn't aware of the parallelism in your code! Be careful! Later + ## versions of `||` will get proper support by Nim's code generator + ## and GC. + discard + +iterator `||`*[S, T](a: S, b: T, step: Positive, annotation: static string = "parallel for"): T {. + inline, magic: "OmpParFor", sideEffect.} = + ## OpenMP parallel loop iterator with stepping. + ## Same as `countup` but the loop may run in parallel. + ## + ## `annotation` is an additional annotation for the code generator to use. + ## The default annotation is `parallel for`. + ## Please refer to the `OpenMP Syntax Reference + ## <https://www.openmp.org/wp-content/uploads/OpenMP-4.5-1115-CPP-web.pdf>`_ + ## for further information. + ## + ## Note that the compiler maps that to + ## the `#pragma omp parallel for` construct of `OpenMP`:idx: and as + ## such isn't aware of the parallelism in your code! Be careful! Later + ## versions of `||` will get proper support by Nim's code generator + ## and GC. + discard |