fiber iterators

[dmazParticipant]

question about how fiber generators will work… the example on the front page used a while loop instead of eachin, is/will there be support for eachin with those?

in c# I’ve done this in a vector class I use for grids.

[code]    public IEnumerable<IntVector2> Neighbours {
yield return this + left;
yield return this + right;
yield return this + up;
yield return this + down;
}[/code] Which allows me to do

for(IntVector2 v2 in location.Neighbours()) {}

in monkey2, will I need to extend something like Generator(as mentioned on the blog) or implement HasNext(), GetNext() etc…  ?   is there some way to hide some of  this?

[Mark SiblyKeymaster]

To do this right now, the obvious way would be to subclass something like the Generator<T> class with a NeighborGenerator<Vector2> class. That would work, but it’s not as elegant as an enumerator method.

An interesting potential alternative would be to ‘push’ the neighbors to a generator (consumer?) eg:

Monkey

Method Neighbors( g:Generator<Vector2> )    g.Yield( this+up )    g.Yield( this+left )    ...etc... End

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Method Neighbors( g:Generator<Vector2> )      g.Yield( this+up )      g.Yield( this+left )      ...etc...   End

Then, a global function like ‘Generate’ could be used to do the generation (not sure if it’s this simple…!) eg:

Monkey

Function Generate<T>:Generator<T>( func( g:Generator<T> ) ) Local g:=new Generator<T> func( g ) Return g End

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Function Generate<T>:Generator<T>( func( g:Generator<T> ) )      Local g:=new Generator<T>    func( g )    Return g   End

…which could be used by client code like this…

Monkey

Function Main()    For Local v2:=Eachin Generate( v1.Neighbors )       ...    Next End

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Function Main()      For Local v2:=Eachin Generate( v1.Neighbors )         ...      Next   End

This is actually kind of interesting – instead of the Neighbors method returning a ‘producer’ ala c#, we do the opposite and pass it a ‘consumer’.

If course, it’d be nice to support both approaches, and the compiler can indeed help (although it’s *really* nice if it doesn’t have to, or a minor tweak ‘enables’ something cool like this!), but I’m still getting my head around a lot of this stuff and don’t want to commit to anything yet.

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