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

[Regan Heath]

On Thu, 20 Feb 2014 16:30:42 -0000, Justin Whear  
<justin at 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?

R

-- 
Using Opera's revolutionary email client: http://www.opera.com/mail/