Automatic Foreach

[janderson]

Bill Baxter wrote:
> janderson wrote:
>> Bill Baxter wrote:
>>> janderson wrote:
>>>> What do you think?
>>>
>>> I think it's already hard enough to figure out what's going to get 
>>> called by something like foo(array)
>>>
>>> It could be
>>> - foo(int[] x)
>>> - foo(int[] x...)
>>> - foo(T)(T x)
>>> - foo(T)(T[] x)
>>> - foo(T...)(T x)
>>> - struct foo { static foo opCall(int[]); }
>>> - struct foo { static foo opCall(int[]...); }
>>> - struct foo { static foo opCall(T)(T x); }  etc
>>> - or struct Foo with non-static opCall on instance foo
>>> - or all the same stuff on class  ...
>>>
>>> So I don't think another meaning for foo(array) is really helpful.
>>>
>>> I *do* like the idea of an expression (not a statement) that has 
>>> foreach-like abilities.  But I think it should come with some 
>>> distinguishing syntax.
>>>
>>> In Python it's just [expr(x) for x in array]
>>> Which resonates with Pythons normal loopoing:
>>>    for x in array: expr(x)
>>>
>>> So direct translation of that idea to D would be
>>>    [expr(x) foreach(x; array)];
>>>
>>> Seems not so terrible a syntax to me.
>>>
>>> --bb
>>
>> I think I prefer:
>>
>> foo(array[]);
> 
> I think that already means call foo with a full slice of array, doesn't 
> it?  Anyway, even if it doesn't you can overload opSlice() currently so 
> that array[] can mean anything you want it to.
> 
> --bb

That's the point though.  If there's already an overload available then 
that should be used.  It allows you to come along later and write 
specialized behavior.

-Joel