SEXP-parser in LISP


parseWS xs -> all \Space xs
parseNumber [@xs] -> if (all digit? xs) then asBase 10 xs
parseSymbol [@xs] -> if (all alpha? xs) then asSymbol xs
parseRest x -> x.{[] => 'nil; [@!WS] => 'nil
                  [\Space @!WS e:!Sexp es:!Rest] => if es=='nil [e] [e@es]}
parseList xs -> parseRest [\Space @xs]
parseSexp x -> x.{[e:!Number]=>e; [e:!Symbol]=>e
                  [\( @!WS es:!List \)] => e}

Whenever i see ``xs'', especially when used in pattern matching like x::xs to denote an element and the rest of the list, I think of it like: the CAR is x, REST are xs (plural of ``x'').