add `remove-duplicates'

svn: r14278 original commit: f48dbda950dc70be1966a352ded70bd12a339a24
2009-03-25 17:22:09 +00:00 · 2009-03-25 17:22:09 +00:00 · 44a858ba4a
commit 44a858ba4a
parent 23a33e158c
1 changed files with 5 additions and 0 deletions
--- a/collects/typed-scheme/private/base-env.ss
+++ b/collects/typed-scheme/private/base-env.ss
@ -550,6 +550,11 @@
 [last-pair (-poly (a) ((-mu x (Un a (-val '()) (-pair a x)))
                       . -> . 
                       (Un (-pair a a) (-pair a (-val '())))))]
+[remove-duplicates
+ (-poly (a)
+        (cl->*
+         ((-lst a) . -> . (-lst a))
+         ((-lst a) (a a . -> . Univ) . -> . (-lst a))))]

 ;; scheme/tcp
 [tcp-listener? (make-pred-ty -TCP-Listener)]