Now we have the alphaNumChar () into the code, I thought my program should make use of it. The slight problem is we die in the parse- AndElaborate pass of the compiler with: Error: ../lib/mlton-stubs/mlton.sig 34.26: undefined signature MLTON_POINTER Is this reproduceable anywhere else, or is it my 14 Dec compiler which needs upgrading? (Arch is NetBSD). -- j.