; Haskell style list comprehension
; Copyright 2005 Brian Alliet

; [expr|guard, pat <- gen] => (list-comp expr guard (pat <- gen))
; FEATURE: Optimize this, right now it generates too many 1 element lists
(define-syntax list-comp
    (syntax-rules (<-)
        ((list-comp e) (cons e '()))
        ((list-comp e (p <- l) q ...) 
            (concat-map
                (lambda-match
                    (p (list-comp e q ...))
                    (_ '())
                ) l))
        ((list-comp e b q ...) (if b (list-comp e q ...) '()))
    ))