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pollen/pollen/tag.rkt

107 lines
5.5 KiB
Racket

#lang pollen/mode racket/base
(require (for-syntax racket/base syntax/parse))
(require txexpr/base racket/string racket/match)
(provide default-tag-function make-default-tag-function define-tag-function)
(define (parse-leading-attrs xs)
(match xs
[(cons (? txexpr-attrs? leading-attrs) tail) (values leading-attrs tail)]
[else (values null xs)]))
(define (parse-colon-attrs xs)
(define (colon-attr-name? x)
(and (symbol? x)
(let ([result (regexp-match #rx".*?(?=:$)" (symbol->string x))])
(and (pair? result) (string->symbol (car result))))))
(let parse-next ([xs xs][colon-attrs empty])
(match xs
[(list* (? colon-attr-name? name) (? string? val) xs)
(parse-next xs (cons (list (colon-attr-name? name) val) colon-attrs))]
[else (values colon-attrs xs)])))
(define (parse-kw-attrs kw-symbols-in kw-args)
(define kw-symbols (map (λ (kw) (string->symbol (string-trim (keyword->string kw) "#:"))) kw-symbols-in))
(map list kw-symbols kw-args))
(define (make-one-tag-function outer-kws outer-kw-args id)
(make-keyword-procedure
(λ (inner-kws inner-kw-args . xs)
;; Three possible sources of attrs:
;; 1) normal attrs, in a list at the front of the args
(let*-values ([(leading-attrs xs) (parse-leading-attrs xs)]
;; 2) colon attrs, using special 'key: "value" syntax, also at the front of the args
[(colon-attrs xs) (parse-colon-attrs xs)]
;; 3) keyword attrs
[(kw-attrs) (parse-kw-attrs (append outer-kws inner-kws) (append outer-kw-args inner-kw-args))])
;; construct the xexpr result "manually" (i.e., not with `make-txexpr` because it may not be a legit txexpr for now
;; (but it may become one through further processing, so no need to be finicky)
;; however, don't show empty attrs.
(define attrs (append kw-attrs colon-attrs leading-attrs))
(cons id (if (null? attrs)
xs
(cons attrs xs)))))))
(define default-tag-function
(make-keyword-procedure
(λ (outer-kws outer-kw-args . ids)
(let ([tag-proc (apply compose1 (for/list ([id (in-list ids)])
(make-one-tag-function outer-kws outer-kw-args id)))]
[tag-proc-name (string->symbol (format "pollen-tag:~a" (string-join (map symbol->string ids) "+")))])
(procedure-rename tag-proc tag-proc-name)))))
(define make-default-tag-function default-tag-function) ; bw compat
(module+ test
(require rackunit txexpr/check)
(define outerdiv (default-tag-function 'div #:class "outer" #:style "outer"))
(check-txexprs-equal? (outerdiv "foo") '(div ((class "outer") (style "outer")) "foo"))
(check-txexprs-equal? (outerdiv) '(div ((class "outer") (style "outer"))))
(check-txexprs-equal? (outerdiv #:class "inner") '(div ((class "outer") (style "outer") (class "inner"))))
(check-txexprs-equal? (outerdiv #:class "inner" "foo") '(div ((class "outer") (style "outer") (class "inner")) "foo"))
(check-txexprs-equal? (outerdiv #:field "greens" #:id "shazbot" "foo") '(div ((class "outer") (style "outer") (field "greens") (id "shazbot")) "foo"))
(check-txexprs-equal? (outerdiv 'id: "shazbot" "foo") '(div ((class "outer") (style "outer") (id "shazbot")) "foo"))
(check-txexprs-equal? (outerdiv '((id "shazbot")) "foo") '(div ((class "outer") (style "outer") (id "shazbot")) "foo"))
(check-txexprs-equal? (outerdiv 'id: "shazbot" 'class: "inner" "foo") '(div ((class "outer") (style "outer") (id "shazbot") (class "inner")) "foo"))
;; (outerdiv 'id: "shazbot" '((class "inner")) "foo") won't work because colon attrs supplant conventional attrs (docs concur)
(check-txexprs-equal? (outerdiv 'id: "shazbot" #:class "inner" "foo") '(div ((class "outer") (style "outer") (class "inner") (id "shazbot")) "foo")))
(define-syntax (define-tag-function stx)
(syntax-parse stx
#:literals (λ)
[(_ (ID:id ARG:id ...) EXPR:expr ...)
#'(define-tag-function ID (λ (ARG ...) EXPR ...))]
[(_ ID:id (λ (ATTRS:id ELEMS:id ARG:id ...) EXPR:expr ...))
#:fail-when (> (length (syntax->list #'(ARG ...))) 0) "tag function must have exactly 2 positional arguments"
#:fail-when (check-duplicate-identifier (list #'ATTRS #'ELEMS)) "duplicate variable name"
#:fail-when (null? (syntax->list #'(EXPR ...))) "body of definition cannot be empty"
#'(define ID
(make-keyword-procedure
(λ (kws kwargs . args)
(define tx-proc (keyword-apply default-tag-function kws kwargs (list 'ID)))
(define tx (apply tx-proc args))
(define-values (_ ATTRS ELEMS) (txexpr->values tx))
EXPR ...)))]))
(module+ test
(require rackunit)
(define foo2 (default-tag-function 'foo))
(define-tag-function (foo attrs elems)
`(foo ,(reverse attrs) ,@elems))
(check-txexprs-equal? ◊foo[#:zim "zam"]{hello} ◊foo2[#:zim "zam"]{hello})
(check-txexprs-equal? ◊foo[#:ding "dong" '((zim "zam"))]{hello} ◊foo2[#:ding "dong" '((zim "zam"))]{hello})
(check-txexprs-equal? ◊foo['zim: "zam" #:ding "dong" ]{hello} ◊foo2['zim: "zam" #:ding "dong" ]{hello})
(define-tag-function foolam (λ (attrs elems)
`(foo ,(reverse attrs) ,@elems)))
(check-txexprs-equal? ◊foolam[#:zim "zam"]{hello} ◊foo2[#:zim "zam"]{hello})
(check-txexprs-equal? ◊foolam[#:ding "dong" '((zim "zam"))]{hello} ◊foo2[#:ding "dong" '((zim "zam"))]{hello})
(check-txexprs-equal? ◊foolam['zim: "zam" #:ding "dong" ]{hello} ◊foo2['zim: "zam" #:ding "dong" ]{hello}))