racket/collects/unstable/match.ss
Sam Tobin-Hochstadt 0ae5843f11 Add unstable/match with == match expander.
Add 'match expander' tech def.

svn: r16814
2009-11-16 16:58:11 +00:00

14 lines
247 B
Scheme

#lang scheme/base
(require scheme/match (for-syntax scheme/base))
(provide ==)
(define-match-expander
==
(lambda (stx)
(syntax-case stx ()
[(_ val comp)
#'(? (lambda (x) (comp val x)))]
[(_ val) #'(== val equal?)])))