CLAST reworked

Prompted by a post on one of the various Common Lisp fora, I finally got my act together and went back to CLAST, i.e., the Common Lisp Abstract Syntax Tree library that I had in the works for ... some time.

The library has an interesting origin, which I will recount in a different post. Suffice to say that eventually I needed a code walker which did a few complicated things. NIH sydrome immediately kicked in.

The main think I needed were functions inspecting code, as in the example below.

cl-prompt> (clast:find-free-variables '(let ((x 42)) (+ x y)))

To achieve this (apparently) simple goal, a (mostly) portable environment library had to be developed and a full set of AST node structures had to be provided.

The result is now finally ready for prime time. In Lispworks you can also see how things actually get parsed. As an example, the picture below shows the result of the following command.

cl-prompt> (clast:parse '(loop for i in '(1 2 3)
                               count (oddp (+ qd i)) into odds))

Please try it, report bugs, blast my design choices and suggest improvements.

Thank you



  1. Update: Clozure CL also passes all the tests now.

    1. The simple UI panel is LW only, but it is just for debugging purposes.

      The rest works on SBCL and Allegro no problems (so far; the folks at Franz ran the test suite many many times to track down a gc buglet with ACL Express 11 and found no problems with the library per se).