Dear all (the few, the self-chosen :) lurking here) I have been fiddling about with a "pattern compiler" to be made part of a compiler-macro for MATCH-CASE. After reading a few things here and there, I came to the conclusion that for CL and CL-UNIFICATION there is no need for anything particularly sophisticated (things like "partial test/evaluation merging" and whatnot), but I also started to think that maybe it would be better to introduce new syntax. Something along the lines of (PAT (<object> &key …) <clauses>) Now. This may look simple, but suppose you wanted to do something like (let ((x 42)) (y 123)) (pat (x y) ((42 123) t) (_ 'not-matched))) Now, while in principle this is easy (you just have a "list" instead of an object as first element), things may become hairy very soon when you want to add keywords affecting the matching process (cfr the MATCH-CASE syntax match-case (<object> &key errorp default-substitution) <clauses> where grouping is used for the keyword variables errorp default-substitution). With this consideration in mind the above example would become (let ((x 42)) (y 123)) (pat ((x y)) ((42 123) t) (_ 'not-matched))) So the questions I have for you are two: (1) do you have any ideas about syntax, even at the cost of introducing some "spurious infix" bit? (2) the PAT above should be really be named MATCH-CASE, but that is already taken; for the sake of backward compatibility, do you think that PAT or CASE-MATCH or SELECT or whatever should be used for the new syntax? Cheers -- Marco Antoniotti