diff options
Diffstat (limited to 'lib/system.nim')
| -rw-r--r-- | lib/system.nim | 35 |
1 files changed, 33 insertions, 2 deletions
diff --git a/lib/system.nim b/lib/system.nim index 5a84f4a52..b4919db2d 100644 --- a/lib/system.nim +++ b/lib/system.nim @@ -669,6 +669,12 @@ proc newSeq*[T](len = 0.Natural): seq[T] = ## #inputStrings[3] = "out of bounds" newSeq(result, len) +proc newSeqOfCap*[T](cap: Natural): seq[T] {. + magic: "NewSeqOfCap", noSideEffect.} = + ## creates a new sequence of type ``seq[T]`` with length 0 and capacity + ## ``cap``. + discard + proc len*[TOpenArray: openArray|varargs](x: TOpenArray): int {. magic: "LengthOpenArray", noSideEffect.} proc len*(x: string): int {.magic: "LengthStr", noSideEffect.} @@ -1523,7 +1529,7 @@ type # these work for most platforms: ## This is the same as the type ``unsigned long long`` in *C*. cstringArray* {.importc: "char**", nodecl.} = ptr - array [0..ArrayDummySize, cstring] + array[0..ArrayDummySize, cstring] ## This is binary compatible to the type ``char**`` in *C*. The array's ## high value is large enough to disable bounds checking in practice. ## Use `cstringArrayToSeq` to convert it into a ``seq[string]``. @@ -3353,7 +3359,11 @@ proc astToStr*[T](x: T): string {.magic: "AstToStr", noSideEffect.} proc instantiationInfo*(index = -1, fullPaths = false): tuple[ filename: string, line: int] {. magic: "InstantiationInfo", noSideEffect.} - ## provides access to the compiler's instantiation stack line information. + ## provides access to the compiler's instantiation stack line information + ## of a template. + ## + ## While similar to the `caller info`:idx: of other languages, it is determined + ## at compile time. ## ## This proc is mostly useful for meta programming (eg. ``assert`` template) ## to retrieve information about the current filename and line number. @@ -3633,6 +3643,27 @@ proc `==` *(x, y: cstring): bool {.magic: "EqCString", noSideEffect, elif x.isNil or y.isNil: result = false else: result = strcmp(x, y) == 0 +template closureScope*(body: untyped): stmt = + ## Useful when creating a closure in a loop to capture local loop variables by + ## their current iteration values. Example: + ## + ## .. code-block:: nim + ## var myClosure : proc() + ## # without closureScope: + ## for i in 0 .. 5: + ## let j = i + ## if j == 3: + ## myClosure = proc() = echo j + ## myClosure() # outputs 5. `j` is changed after closure creation + ## # with closureScope: + ## for i in 0 .. 5: + ## closureScope: # Everything in this scope is locked after closure creation + ## let j = i + ## if j == 3: + ## myClosure = proc() = echo j + ## myClosure() # outputs 3 + (proc() = body)() + {.pop.} #{.push warning[GcMem]: off, warning[Uninit]: off.} when defined(nimconfig): |