[zoybert]

I believe you're misunderstanding what stream fusion is. A language compiler does not really need "good iterator/generator abstractions" more than a guarantee of side-effect free transformations in order to be able to de-forest the intermediate data structures. http://citeseer.ist.psu.edu/viewdoc/summary?doi=10.1.1.104.7...

[windlep]

I meant more that languages with an iterator/generator usually have similar constant space usage. That is a drastic oversimplification of stream fusion and fails to mention other practical outcomes as you mention, along with a variety of optimizations.

I found this posting a little more approachable to seeing the various optimizations possible with stream fusion: https://donsbot.wordpress.com/2008/06/04/haskell-as-fast-as-...