- (c-make-rules '(L ...) '(P X) ...) → '(syntax-rules ...)syntax
Build a CK-macro based on syntax-rules. Added in version 0.3.0.
Given a list of zero or more literal symbols, and one or more pattern/expression lists, yields a syntax-rules form for a CK-macro with the following behavior:
- Given argument(s) that match any pattern P, yields the value of the associated expression X, which may use identifiers from P. Fails if no pattern matches.
Each pattern P is a list of zero or more sub-patterns, which will be matched (as with syntax-rules) against the already-evaluated and quoted arguments given to the new CK-macro. Alternatively, P may be an identifier which will capture all arguments as a list.
Each expression X is a single CK-macro expression or quoted value. Identifiers from the pattern can be used in the expression, as with syntax-rules.
Symbols in the literals list (L ...) will be treated as literal identifiers in patterns. Additionally, quote is always treated as a literal identifier.
- Using ... in a pattern or expression may not work portably with all Scheme systems.
- Symbols begining with %ck: are reserved for internal use and must not appear in any L, P, or X.
(ck () `(define-syntax c-flip-flop ,(c-make-rules '(flip flop) '(('flip 'x 'y) (c-list 'y 'x)) '(('flop 'x 'y) '#f)))) ;; The above is basically equivalent to: ;; (define-syntax c-flip-flop ;; (syntax-rules (flip flop quote) ;; ((_ s 'flip 'x 'y) ;; (ck s (c-list 'y 'x))) ;; ((_ s 'flop 'x 'y) ;; (ck s '#f)))) (ck () (c-quote (c-flip-flop 'flip '1 '2))) ;; ==> '(1 2) (ck () (c-quote (c-flip-flop 'flop '1 '2))) ;; ==> #f