Last sunday, I played around w/ evaluating Python lists like: [ lsetq, S("sum"), [llambda,[S("x"),S("y")], [lplus, S("x"), S("y") ]]] If that seems strangely familiar, check pysexpr out at: http://www.students.tut.fi/~vainio24/pysexpr/ -- Ville Vainio http://www.students.tut.fi/~vainio24