I have some questions about the eta-expansion, which is perfomed in the simplifier. I found in [1], that the transformation "eta-expansion" is of the form v = \a1 ... an -> f a1 ... an ===> v = \a1 ...an ... am -> f a1 ... an ...am assuming f has arity m > n. arity is something like "how many arguments can be applied, without perfoming work" My questions: 1) How do you compute this arity. 2) What's the expression f in the general rule, is it a variable or a term, or could it be both? In the same paper is the case-eta-expansion, but I don't understand the correctness of this transformation: case e of {p1 -> e1,...,pn -> en} ===> \y -> case e of {p1 -> e1 y, ..., pn -> en y} The rhs is a WHNF, but the lhs isn't, so the rule can't be correct in general. For example, assume that e is bot. Regards, David [1] André Santos, Compilation by Transformation in Non-Strict Functional Languages, PhD thesis, TR-1995-17, Department of Computing Science, University of Glasgow, 1995. --------------------------------------------------------------------- David Sabel sabel@cs.uni-frankfurt.de JWGU Frankfurt