trivial/private/function.rkt
2016-03-09 03:25:36 -05:00

52 lines
1.4 KiB
Racket

#lang typed/racket/base
;; Track procedure arity
;; Applications:
;; -
;; - vectorized ops
;; - (TODO) improve apply/map? ask Leif
(provide
curry:
)
;; -----------------------------------------------------------------------------
(require
(for-syntax
typed/racket/base
syntax/parse
trivial/private/common
))
;; =============================================================================
(begin-for-syntax
(define (parse-procedure-arity stx)
(syntax-parse stx #:literals (#%plain-lambda)
[(#%plain-lambda (x*:id ...) e* ...)
(length (syntax-e #'(x* ...)))]
;; TODO polydots, keywords, optional args
;; TODO standard library functions
[_ #f]))
(define-values (arity-key proc? define-proc let-proc)
(make-value-property 'procedure:arity parse-procedure-arity))
(define-syntax-class/predicate procedure/arity proc?)
)
;; -----------------------------------------------------------------------------
(define-syntax (curry: stx)
(syntax-parse stx
[(_ p:procedure/arity)
#:with (x* ...) (for/list ([_i (in-range (syntax-e #'p.evidence))]) (gensym))
#:with p+ (for/fold ([e (quasisyntax/loc stx (p #,@#`#,(reverse (syntax-e #'(x* ...)))))])
([x (in-list (syntax-e #'(x* ...)))])
(quasisyntax/loc stx
(lambda (#,x) #,e)))
(syntax/loc stx p+)]
[_
(raise-user-error 'curry "Fail ~a" (syntax->datum stx))]))