racket/collects/web-server/formlets/syntax.rkt

78 lines
2.4 KiB
Racket

#lang racket
(require (for-syntax racket syntax/parse)
"lib.rkt"
(for-syntax "lib.rkt"))
(define-syntax (#%# stx) (raise-syntax-error '#%# "Only allowed inside formlet" stx))
(define-for-syntax (cross-of stx)
(syntax-parse
stx
#:literals (unquote unquote-splicing => #%# values)
[s:str
(syntax/loc stx empty)]
[,(formlet . => . (values name:id ...)) (syntax/loc stx (vector name ...))]
[,(formlet . => . name:id) (syntax/loc stx name)]
[,e (syntax/loc stx empty)]
[,@e (syntax/loc stx empty)]
[(#%# n ...)
(quasisyntax/loc stx (list #,@(map cross-of (syntax->list #'(n ...)))))]
[(t ([k v] ...) n ...)
(quasisyntax/loc stx (list #,@(map cross-of (syntax->list #'(n ...)))))]
[(t n ...)
(quasisyntax/loc stx (list #,@(map cross-of (syntax->list #'(n ...)))))]))
(define-for-syntax (circ-of stx)
(syntax-parse
stx
#:literals (unquote unquote-splicing => #%# values)
[s:str
(syntax/loc stx (text s))]
[,(formlet . => . (values name:id ...)) (syntax/loc stx (cross (pure (lambda (name ...) (vector name ...))) formlet))]
[,(formlet . => . name:id) (syntax/loc stx formlet)]
[,e (syntax/loc stx (xml e))]
[,@e (syntax/loc stx (xml-forest e))]
[(#%# n ...)
(let ([n-cross (map cross-of (syntax->list #'(n ...)))])
(quasisyntax/loc stx
(cross*
(pure (match-lambda*
[(list #,@n-cross)
(list #,@n-cross)]))
#,@(map circ-of (syntax->list #'(n ...))))))]
[(t ([k v] ...) n ...)
(quasisyntax/loc stx
(tag-xexpr `t `([k v] ...)
#,(circ-of (syntax/loc stx (#%# n ...)))))]
[(t n ...)
(quasisyntax/loc stx
(tag-xexpr `t empty
#,(circ-of (syntax/loc stx (#%# n ...)))))]))
(define-syntax (formlet stx)
(syntax-case stx ()
[(_ q e)
(quasisyntax/loc stx
(cross (pure (match-lambda [#,(cross-of #'q) e]))
#,(circ-of #'q)))]))
(provide formlet #%#)
(require "input.rkt")
(define date-formlet
(formlet
(div
"Month:" ,{input-int . => . month}
"Day:" ,{input-int . => . day})
(values month day)))
(define travel-formlet
(formlet
(div
"Name:" ,{input-string . => . name}
(div
"Arrive:" ,{date-formlet . => . (values arrive-m arrive-d)}
"Depart:" ,{date-formlet . => . (values depart-m depart-d)})
,@(list "1" "2" "3"))
(values name arrive-m arrive-d depart-m depart-d)))