trivial/private/function.rkt
2016-03-19 08:47:49 -04:00

119 lines
3.4 KiB
Racket

#lang typed/racket/base
;; TODO get type from a lambda AFTER expansion
;
;(require
; (for-syntax
; (only-in typed-racket/private/syntax-properties plambda-property)))
;
;; -----------------------------------------------------------------------------
;; Track procedure arity
;; Applications:
;; -
;; - vectorized ops
;; - (TODO) improve apply/map? ask Leif
;; - TODO get types, not arity
(provide
curry:
map:
;; --
(for-syntax
fun-define
fun-let)
)
;; -----------------------------------------------------------------------------
(require
(for-syntax
typed/racket/base
syntax/parse
racket/syntax
trivial/private/common
))
;(require
; (prefix-in tr: typed/racket/base)
; (prefix-in r: (only-in racket/base quote))
; (for-syntax
; syntax/id-table))
;; =============================================================================
(begin-for-syntax
(define TYPE-KEY 'type-label)
(define (parse-procedure-arity stx)
(syntax-parse stx #:literals (: #%plain-lambda lambda)
[(#%plain-lambda (x*:id ...) e* ...)
(syntax/loc stx (x* ...))]
;; TODO polydots, keywords, optional args
;; TODO standard library functions
[_ #f]))
(define-values (arity-key fun? fun-define fun-let)
(make-value-property 'procedure:arity parse-procedure-arity))
(define-syntax-class/predicate procedure/arity fun?)
)
;; -----------------------------------------------------------------------------
(define-syntax (curry: stx)
(syntax-parse stx
[(_ p:procedure/arity)
#:with p+ (for/fold ([e (quasisyntax/loc stx (p.expanded #,@#'p.evidence))])
([x (in-list (reverse (syntax-e #'p.evidence)))])
(quasisyntax/loc stx
(lambda (#,x) #,e)))
(syntax/loc stx p+)]
[_
(raise-user-error 'curry "Fail at: ~a" (syntax->datum stx))]))
;; TODO try the other direction, inferring type from arguments.
;; (may not be practical here, may need to be inside TR)
(define-syntax map: (make-alias #'map
(lambda (stx) (syntax-parse stx
[(_ p:procedure/arity e* ...)
;; --
#:when
(let ([num-expected (length (syntax-e #'p.evidence))]
[num-actual (length (syntax-e #'(e* ...)))])
(unless (= num-expected num-actual)
(apply raise-arity-error
'map:
num-expected
(map syntax->datum (syntax-e #'(e* ...))))))
;; --
#:with Listof-stx (format-id stx "Listof")
#:with (e+* ...)
(for/list ([t (in-list (syntax-e #'p.evidence))]
[e (in-list (syntax-e #'(e* ...)))])
(quasisyntax/loc stx (ann #,e (Listof-stx #,t))))
(syntax/loc stx (map p.expanded e+* ...))]
[(_ p e* ...)
;; TODO -- this case should be subsumed by the last
#:with p+ (expand-expr #'p)
#:with evi (fun? #'p+)
#:when (syntax-e #'evi)
#:when
(let ([num-expected (length (syntax-e #'evi))]
[num-actual (length (syntax-e #'(e* ...)))])
(unless (= num-expected num-actual)
(apply raise-arity-error
'map:
num-expected
(map syntax->datum (syntax-e #'(e* ...))))))
;; --
#:with Listof-stx (format-id stx "Listof")
#:with (e+* ...)
(for/list ([t (in-list (syntax-e #'evi))]
[e (in-list (syntax-e #'(e* ...)))])
;; TODO stop using format-id
(quasisyntax/loc stx (ann #,e (Listof-stx #,(format-id stx "~a" t)))))
(syntax/loc stx (map p+ e+* ...))]))))