[Haskell-cafe] simple Haskell question - List comprehensions

[Miguel Mitrofanov]

> Exercise:
> Show how the single comprehension [(x,y) | x <- [1,2,3], y <-  
> [4,5,6]] with two generators can be re-expressed using two  
> comprehensions with single generators.
> Hint: make use of the library function _concat_.

Another hint: it can be rewritten as

concatMap (\x -> concatMap (\y -> [(x,y)]) [4,5,6]) [1,2,3]