Comment by bjourne

Afaik, Haskell is a realization of the (typed!) lambda calculus. Lisps aren't because they don't do lazy evaluation. The LC beta reduction of (\a. a) (\c. d) (\e. f) is (\c. d) (\e. f) but most lisps will reduce it to (\a. a) d. This might seem like a minor detail but means general recursion using the y combinator isn't actually implementable in lisps (I could be wrong though).