foreach range with index

[Steven Schveighoffer via Digitalmars-d]

On 6/14/17 12:35 PM, Luís Marques wrote:
> On Wednesday, 14 June 2017 at 16:17:50 UTC, Steven Schveighoffer wrote:
>> I don't know if there is room to allow range-defined indexes and
>> foreach-defined indexes. foreach(a, b; someRange) has to do one or the
>> other. Otherwise, changes to how someRange operates can make this a
>> completely different operation.
>
> Seems like exactly what we want. If you add a customization to someRange
> to change the iteration behavior then each relevant foreach
> automatically switches from the default to the requested behavior.
> That's exactly the point of programming to abstract interfaces.

For example:

foreach(i, v; hashmap) => i is counter, v is value

Later hashmap adds support for iterating key and value. Now i is key, v 
is value. Code means something completely different.

Compare with

foreach(i, v; hashmap.enumerate)

Intent is clear from the code.

-Steve