Re: Ruby-style "each" in D?

[Simen Kjærås]

On 2014-03-20 14:16, Andrea Fontana wrote:

On Thursday, 20 March 2014 at 12:32:49 UTC, w0rp wrote:

// std.parallelism parallel function here.
someRange.whatever.parallel(numberOfUnits).each!doSomething

+1

This works:
foreach(i; [0,1,2,3,4,5].parallel) i.writeln;

This works:
[0,1,2,3,4,5].each!writeln;

This won't compile:
[0,1,2,3,4,5].parallel.each!writeln;

Error: template tmp.each cannot deduce function from argument types
!(writeln)(ParallelForeach!(int[])), candidates are:
/tmp/tmp.d(9):        tmp.each(alias fun, Range)(Range range) if
(isInputRange!Range)

It could be made to work, though:

template isIterable(T) {
    enum isIterable = is(typeof((T t){foreach (e; t){}}));
}

template isRefIterable(T) {
    enum isRefIterable = is(typeof((T t){foreach (ref e; t){}}));
}

void each(alias fun, Range)(Range range)
    if (isInputRange!Range)
{
    while (!range.empty)
    {
        unaryFun!fun(range.front);
        range.popFront();
    }
}

void each(alias fun, Range)(Range range)
    if (!isInputRange!Range && isRefIterable!Range)
{
    foreach (ref e; range) {
        unaryFun!fun(e);
    }
}

void each(alias fun, Range)(Range range)
    if (!isInputRange!Range && isIterable!Range && !isRefIterable!Range)
{
    foreach (e; range) {
        unaryFun!fun(e);
    }
}

void main() {
    [0,1,2,3,4,5].parallel.each!writeln;
}

--
  Simen