Re: Mixin - to get to the content-type `MapResult!(__lambda1, int[]).MapResult`

[Dennis Ritchie via Digitalmars-d-learn]

On Sunday, 31 May 2015 at 07:28:02 UTC, Ali Çehreli wrote:
So, you want to skip that extra func() call and have the code 
be "inlined". That's one of the things what any decent 
optimizing compiler does anyway.

Yes, I think that there is an extra function call, because DMD is 
based on Zortech C++ backend, so I figured ... :)

I hear great things especially about ldc and that gdc is just 
good enough. Of course, one needs to check the assembly output 
to be sure that there is no extra function calls.

Ali

And yet in DMD I'm not sure :)

import std.stdio, std.algorithm;

static int idx;

void walk(R)(R range) {
        while (!range.empty) {
                range.front;
                range.popFront;
        }
}

struct Tap(alias func, R)
{
        R range;
        
        alias range this;
        
        @property auto front()
        {
                func(range.front);
                return range.front;
        }
}

auto tap(alias func, R)(R range)
{
        writeln(__FUNCTION__); // ???
        return Tap!(func, R)(range);
}

void main() {
        [5, 6, 7]
                .map!(a => [idx++, a])
                .tap!((a) { writeln(a[1..$]); })
                .walk;
}