Daniel Fischer wrote:

Hi, I have recently come across the curious phenomenon that ghci is sometimes much slower than hugs.

[...]

ms as = zipWith (+) (zipWith (*) as (1:ms as)) (0:1:ms as)

Hugs has(**) a specific optimisation for the case where the left hand side of the declaration occurs as a subexpression in the right hand side. You can get a similar benefit under ghci if you share the common subexpression by hand: ms' as = let bs = ms' as in zipWith (+) (zipWith (*) as (1:bs)) (0:1:bs) (**) I haven't actually seen the code in question, and am repeating something which was on one of the mailing lists a few years ago. So please don't treat this as authoritative! Regards, Tom