foreach, an analogy

[Bill Baxter]

Lionello Lunesu wrote:
> janderson wrote:
>> Walter Bright wrote:
>>> Bruno Medeiros wrote:
>>>> As of DMD now, the only advantage in 'foreach_reverse' is 
>>>> ephemerous: it allows efficient reverse iteration of arrays.
>>>
>>> That's the most important use case.
>>>
>>>> But couldn't the compiler easily detect this:
>>>>   foreach(Foo f; &fooarray.opApplyReverse) { ...
>>>> and and compile it as if it were a:
>>>>   foreach_reverse(Foo f; fooarray) { ...
>>>
>>> Yes, it could. But it looks like a hack. A little syntactic sugar 
>>> makes a big difference.
>>
>>
>> What about:
>>
>> foreach (Foo f; array.reverse) {}
>>
>> The compiler would optimize.
> 
> But the array would still be reversed after the foreach.
> 
> L.

Is that what he was talking about?  I forgot that 'reverse' was an 
actual existing method that mutates the array.  If that's what you 
meant, then, yeh, what Lionello said.

--bb