improve checker for optional keywords

svn: r15432
2009-07-11 15:23:07 +00:00 · 2009-07-11 15:23:07 +00:00 · ba87f38f72
commit ba87f38f72
parent ab46f655c7
1 changed files with 7 additions and 0 deletions
--- a/collects/scheme/private/kw.ss
+++ b/collects/scheme/private/kw.ss
@ -666,6 +666,13 @@
    (syntax-case stx (quote)
      [(_ l1-expr '()) #'(null? l1-expr)]
      [(_ '() l2-expr) #'#t]
+      [(_ l1-expr '(kw . kws)) #'(let ([l1 l1-expr])
+                                   (let ([l1 (if (null? l1)
+                                                 l1
+                                                 (if (eq? (car l1) 'kw)
+                                                     (cdr l1)
+                                                     l1))])
+                                     (subset?/static l1 'kws)))]
      [(_ l1-expr l2-expr) #'(subset? l1-expr l2-expr)]))

  (define-syntax (subsets?/static stx)