Thu Aug 20 11:28:14 CEST 2009

Pattern matching for EX

This really shouldn't be so difficult: from the data structures, it
would be a generation of a couple of CPP macros that setup a lexical
environment.  It would require some trickery with curly braces though.

   CASE(pair, a, d) { }
   CASE(NIL)        { }
   ELSE             { }

where MATCH sets up the first '{' and each CASE starts with a '}'.