racket/collects/redex/private/keyword-macros.rkt

57 lines
2.1 KiB
Racket

#lang racket
(require (for-template racket/base racket/contract))
(define (parse-kw-args formals actuals source form-name)
(let loop ([current (for/hash ([arg formals]) (values (car arg) #f))]
[rest actuals])
(syntax-case rest ()
[() (map (λ (arg)
(match (hash-ref current (car arg))
[#f (cadr arg)]
[x (match (cdr (cdr arg))
['() x]
[`((,ctc ,desc))
(apply-contract ctc x desc form-name)])]))
formals)]
[(kw . rest)
(not (keyword? (syntax-e (syntax kw))))
(raise-syntax-error #f "expected a keyword" source (syntax kw))]
[(kw arg . rest)
(keyword? (syntax-e (syntax arg)))
(raise-syntax-error #f "expected an argument expression" source (syntax arg))]
[(kw arg . rest)
(let ([none (gensym)])
(eq? none (hash-ref current (syntax-e (syntax kw)) none)))
(raise-syntax-error #f "invalid keyword" source (syntax kw))]
[(kw arg . rest)
(hash-ref current (syntax-e (syntax kw)))
(raise-syntax-error #f "repeated keyword" source (syntax kw))]
[(kw)
(raise-syntax-error #f "missing argument expression after keyword" source (syntax kw))]
[(kw arg . rest)
(loop (hash-set current (syntax-e (syntax kw)) (syntax arg))
(syntax rest))]
[else (raise-syntax-error #f "bad keyword argument syntax" source rest)])))
(define (client-name stx form)
(let ([m (syntax-source-module stx)])
(cond [(module-path-index? m)
(format "~a" (module-path-index-resolve m))]
[(or (symbol? m) (path? m))
(format "~a" m)]
[else (format "~s client" form)])))
(define (src-loc-stx stx)
#`#(#,(syntax-source stx)
#,(syntax-line stx)
#,(syntax-column stx)
#,(syntax-position stx)
#,(syntax-span stx)))
(define (apply-contract ctc expr desc form)
#`(contract #,ctc #,expr
#,(client-name expr form) '#,form
#,desc #,(src-loc-stx expr)))
(provide (all-defined-out))