I'm not sure what your question means. You can make your own continuations, so in that sense Haskell has them. But perhaps you're asking why Haskell lacks something like call/cc in Scheme which allows you to grab the current continuation? This doesn't play very well with graph reduction (which most Haskell implementations use), since with graph reduction you will update application nodes with the result of the computation. If you have call/cc available you can "jump back in time" and have a function call return something different, which would contradict the "cached" result from the previous call. It's not an insurmountable problem, but it's pretty hairy.
-- Lennart
Scott wrote:
Why does Haskell have no continuations? (http://www.haskell.org/hawiki/CoMonad)
If continuations are incompatible with non-strict semantics, I'd appreciate an explanation.
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