diff options
Diffstat (limited to 'algebraic-structures.foldable.scm')
| -rw-r--r-- | algebraic-structures.foldable.scm | 17 |
1 files changed, 15 insertions, 2 deletions
diff --git a/algebraic-structures.foldable.scm b/algebraic-structures.foldable.scm index be3d615..25c66bb 100644 --- a/algebraic-structures.foldable.scm +++ b/algebraic-structures.foldable.scm @@ -3,10 +3,11 @@ length count any - every) + every + member?) (import (except scheme length) F - (only (chicken base) add1 call/cc)) + (only (chicken base) add1 call/cc assert)) (define (length xs) (fold (lambda (_ acc) (add1 acc)) @@ -36,4 +37,16 @@ (fold (lambda (e acc) (or (pred e) (return #f))) #t + xs)))) + + (define (member? x xs #!optional (= equal?)) + (call/cc + (lambda (return) + (fold (lambda (e _) + (if (= e x) + (return #t) + #f)) + #f xs))))) + + |