Hello! This is about a misconception I had about zip comprehensions and a possible extension to get the desired result. As zip compr. are implemented in hugs and in ghc (though I only tried hugs), I thought that haskell-cafe might be a good place for it. In hugs mode, I expected something like the following to work: [ (a,a*x) | x <- [1..5] | y <- [10..], let a=x+y ] but hugs says: ERROR - Undefined variable "x" I think I can see why: The expression is rewritten to [ (a,a*x) | (x,y) <- zip [ x | x<-[1..5] ] [ y | y <- [10..], let a=x+y ] ] This scheme is useful if one has ...|y<-list, let a=..., sometest a which drops some elements from the list before zipping. But it would be nice to have a way to drop already zipped tuples and to allow such usages of local declarations. Maybe a final '|' branch without generator, so to get what was intended with the expression above one might write [ (a,a*x) | x <- [1..5] | y <- [10..] | let a=x+y ] or, as another example, one could have [ (x,y) | x <- [1..5] | y <- [10..] | even x ] giving [(2,11),(4,13)]. So the idea is to rewrite [ e | oldstyle parallel list comprehension | declsandpreds ] to [ e | zipN <as before...> , declsandpreds ] Is this clear enough? Does it sound useful? Can you think of a nicer syntax? All the best Christian Sievers