66 lines
2.6 KiB
Scheme
66 lines
2.6 KiB
Scheme
#lang scheme/base
|
|
|
|
(provide negate curry curryr)
|
|
|
|
(define (negate f)
|
|
(unless (procedure? f) (raise-type-error 'negate "procedure" f))
|
|
(let-values ([(arity) (procedure-arity f)]
|
|
[(required-kws accepted-kws) (procedure-keywords f)])
|
|
(define negated ; simple version, optimize some cases
|
|
(case arity
|
|
[(0) (lambda () (not (f)))]
|
|
[(1) (lambda (x) (not (f x)))]
|
|
[(2) (lambda (x y) (not (f x y)))]
|
|
[else (lambda xs (not (apply f xs)))]))
|
|
(if (and (null? required-kws) (null? accepted-kws))
|
|
negated
|
|
;; keyworded function
|
|
(make-keyword-procedure (lambda (kws kvs . args)
|
|
(not (keyword-apply f kws kvs args)))
|
|
negated))))
|
|
|
|
(define (make-curry right?)
|
|
;; The real code is here
|
|
(define (curry* f args kws kvs)
|
|
(unless (procedure? f)
|
|
(raise-type-error (if right? 'curryr 'curry) "procedure" f))
|
|
(let* ([arity (procedure-arity f)]
|
|
[max-arity (cond [(integer? arity) arity]
|
|
[(arity-at-least? arity) #f]
|
|
[(ormap arity-at-least? arity) #f]
|
|
[else (apply max arity)])]
|
|
[n (length args)])
|
|
(define (loop args n)
|
|
(cond
|
|
[(procedure-arity-includes? f n)
|
|
(if (null? kws) (apply f args) (keyword-apply f kws kvs args))]
|
|
[(and max-arity (n . > . max-arity))
|
|
(apply raise-arity-error f arity args)]
|
|
[else
|
|
(letrec [(curried
|
|
(case-lambda
|
|
[() curried] ; return itself on zero arguments
|
|
[more (loop (if right?
|
|
(append more args) (append args more))
|
|
(+ n (length more)))]))]
|
|
curried)]))
|
|
;; take at least one step if we can continue (there is a higher arity)
|
|
(if (equal? n max-arity)
|
|
(if (null? kws) (apply f args) (keyword-apply f kws kvs args))
|
|
(letrec ([curried
|
|
(lambda more
|
|
(let ([args (if right?
|
|
(append more args) (append args more))])
|
|
(loop args (+ n (length more)))))])
|
|
curried))))
|
|
;; curry is itself curried -- if we get args then they're the first step
|
|
(define curry
|
|
(case-lambda [(f) (define (curried . args) (curry* f args '() '()))
|
|
curried]
|
|
[(f . args) (curry* f args '() '())]))
|
|
(make-keyword-procedure (lambda (kws kvs f . args) (curry* f args kws kvs))
|
|
curry))
|
|
|
|
(define curry (make-curry #f))
|
|
(define curryr (make-curry #t))
|