Sorry, it is of course Jan-Willem's compiler that is called Eager Haskell, the Ghc version was called optimistic Haskell. There's also the old precursor to these, the Optimistic G-machine, that performs some non-lazy computations. (And it can even do them while garbage collecting!) -- Lennart On Sep 15, 2006, at 07:59 , Lennart Augustsson wrote:
No, I wasn't suggesting that evaluate can tell the difference, just that you can add dubious "functions".
You can evaluate with eager evaluation and some kind of threads +fair scheduler. Both pH and the (short lived) Eager Haskell version of ghc did this. (Well, I'm not sure pH ever got the fair scheduler.)
-- Lennart
On Sep 15, 2006, at 05:00 , apfelmus@quantentunnel.de wrote:
Lennart Augustsson wrote:
No, you were right the first time. :) The denotational semantics is the important one. Haskell can be executed by other means than graph reduction. (That's why the report says a "non-strict" rather than "lazy" language.) Peculiar language constructs may allow you to tell the difference, but then they are highly dubious (and like all dubious things, they should be in the IO monad :) ).
You suggest that (evaluate) or something else actually can tell me the difference? That would be interesting.
And what alternatives (besides call by name without sharing) are there? I always think lazy evaluation is space and time optimal.
Regards, apfelmus
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