Proposal: delegates as aggregates in foreach statements

[Oskar Linde]

Chris Nicholson-Sauls skrev:

> I think what I had in mind (and just didn't "vocalize") in using 
> anonymous delegates, was to use them like wrappers around a list of 
> other delegate calls or the like (multi-phase looping, perhaps).  I do 
> see your point that in most cases if you were going to do that, you may 
> as well just write the logic into the iteration block itself.  The 
> tree-walkers and suchlike that you mention, though -- that's exactly the 
> sort of thing I'm after. Being able to just do (foreach (i, x; 
> &tree.walkInOrder) {...}) with .walkInOrder() being a simple method 
> would be, pardon the colloquialism, wicked sweet.

You get it almost as sweet and simple by using a a wrapper struct. See 
for instance Andrew Fedoniouk's tree implementation:

http://www.digitalmars.com/d/archives/digitalmars/D/dtl/378.html

That allows:

foreach(Node n; parent.forward) // all children from first to last
foreach(Node n; parent.backward) // all children from last to first
foreach(Node n; parent.deep) // all descendants - children and their

/Oskar