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

[Regan Heath]

On Fri, 21 Feb 2014 19:42:41 -0000, Jesse Phillips  
<Jesse.K.Phillips+D at gmail.com> wrote:
> On Friday, 21 February 2014 at 16:41:00 UTC, Regan Heath wrote:
>> and make this possible too:
>>
>> 	foreach([index, ]value; range) { }
>
> I understand the user interface is simple, but you created 3 statements  
> about how it could be achieved and work/not work with the existing  
> setup. Each have their positives and negatives, it would not make sense  
> to "just choose one" and hope it all works out.
>
>>> if AA is changed to a double[string], then your value loop iterates on  
>>> keys and your key loop iterates on values.
>>
>> No, I was actually suggesting a change here, the compiler would use  
>> type matching not ordering to assign the variables.  So because 'v' is  
>> a string, it is bound to the value not the key.
>
> And string is the key, double[string] is not the same as string[double].
>
> Also string[string], ambiguous yet common.
>
> There are many things to consider when adding a feature, it is not good  
> to ignore what can go wrong.

Yes.. something is not being communicated here.  I addressed all this in  
the OP.

>> Thanks!  Ok, so how is this working?  ahh, ok I think I get it.
>>  enumerate returns a range, whose values are Tuples of index/value  
>> where value is also a tuple so is flattened, and then the whole lot is  
>> flattened into the foreach.
>
> Sounds like you understand it, seams foreach will flatten all tuples.
>
>> I don't think this affects what I actually want to change, we can have:
>>
>> 	foreach(index, value; range) { }
>>
>> and still flatten tuples into value, you would simply have to provide  
>> one extra variable to get an index.
>>
>> Make sense?
>
> Yes, but I'm saying we don't need it because
>
> 	foreach(index, value; range.enumerate) { }
>
> is good enough. Not perfect, but good enough.

No, not good enough.  This should just work, there is no good reason for  
it not to.

R

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