Re: Repost: make foreach(i, a; range) "just work"

[Regan Heath]

On Fri, 21 Feb 2014 10:02:43 -0000, Regan Heath <re...@netmail.co.nz>  
wrote:

On Thu, 20 Feb 2014 16:30:42 -0000, Justin Whear  
<jus...@economicmodeling.com> wrote:

On Thu, 20 Feb 2014 13:04:55 +0000, w0rp wrote:

More importantly, this gets in the way of behaviour which may be
desirable later, foreach being able to unpack tuples from ranges.
I would like if it was possible to return Tuple!(A, B) from front() and
write foreach(a, b; range) to interate through those thing, unpacking
the values with an alias, so this...

foreach(a, b; range) {
}

... could rewrite to roughly this. (There may be a better way.)

foreach(_someInternalName; range) {
     alias a = _someInternalName[0];
     alias b = _someInternalName[1];
}

Tuple unpacking already works in foreach.  This code has compiled since
at least 2.063.2:

import std.stdio;
import std.range;
void main(string[] args)
{
    auto tuples = ["a", "b", "c"].zip(iota(0, 3));

    // unpack the string into `s`, the integer into `i`
    foreach (s, i; tuples)
        writeln(s, ", ", i);
}

Does this work for more than 2 values?  Can the first value be something  
other than an integer?

Answered this myself.  What is supported is:

        foreach(key, value; tuple) { }

But, what is not supported is more than 2 values.

R

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