gensym and hygienic macro
Posted: Thu Aug 03, 2006 6:29 pm
OK, while I was thinking, and learning newLisp, and tried to implement a gensym a gensym. It does not technically give you an unlimited number of different different symbols, but it should be enough for most real world problems.
And a macro to create hygienic macros, using gensym.
Disclaimer: I'm a newbie when it comes to newLisp (and the whole lisp family), so take my code with a grain of salt. ;-)
Comments are highly appreciated.
Ingo
Code: Select all
(context 'gensym)
(set 'no 0)
(define (gensym:gensym)
"creates lots of unique symbols ... is that enough?"
(sym (string "___" (inc 'no 0.1))))
(context MAIN)
Code: Select all
(define-macro (def-macro)
"creates macro definitions with automatically created symbols"
(let ((__def-macro_def (clean (fn (x) (= ', x)) (rest (args 0))))
(__def-macro_sym '()))
(dolist (__def-macro_ __def-macro_def)
(push (list __def-macro_ (gensym)) __def-macro_sym))
(set '__def-macro_def (expand (args) __def-macro_sym))
(push 'define-macro __def-macro_def)
(eval __def-macro_def)
)
)
Comments are highly appreciated.
Ingo