foreach, an analogy

[Pragma]

Jarrett Billingsley wrote:
> You can have:
> 
> something.each((int item) {
>     writefln(item);
> });

I like the look of that.  I've been doing a lot of Javascript coding 
with Prototype lately, and I really gotten used to using closures in 
this way.

But it's almost a parallel solution to for/foreach anyway.  If IFTI were 
a little smarter, you wouldn't need compiler support to pull it off.  As 
a bonus, that would mean that all the other kinds of iteration 
imaginable (unordered, reverse, sorted, etc) would just be additional 
iterator templates.

// fn returns false to break the loop, true to continue
void each(T)(T[] arr, int delegate(inout T) fn){
     for(uint i=0; i<arr.length; i++) if(!fn(arr[i])) break;
}

void reverse(T)(T[] arr, int delegate(inout T) fn){
     for(uint i=length-1; i>=0; i--) if!(fn(arr[i])) break;
}

AFAIK, I'm mostly sure this will work now.  Haven't tried it though.

Aside from not being able to use break and continue to control the loop 
behavior, I'd happily use a library that does this.  Prototype uses 
"throw BREAK;" (where 'BREAK' is a constant defined elsewhere) which 
might be a better looking solution, if a bit kludgey.

- EricAnderton at yahoo