[Haskell-cafe] Looking at program execution

[Ian Duncan]

Is there any way to view the steps that a haskell program goes  
through step by step?
I'm thinking something similar to what I've seen in things I've been  
reading. For example:
foldl (+) 0 [1..10]
=> (0+1)
=> ((0+1)+2)
=> (((0+1)+2)+3)
=> etc.
I've seen these sorts of line-by-line execution steps, but I was  
curious if there was any way to simply type in a function and its  
arguments and have ghci or hugs or something print out this sort of  
visual representation of what's going on. Anyone know of something  
like this?