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pollen/decode.rkt

74 lines
3.4 KiB
Racket

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#lang racket/base
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(require xml txexpr sugar/define)
(require "decode/block.rkt" "decode/typography.rkt" "debug.rkt")
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(provide (all-from-out "decode/block.rkt" "decode/typography.rkt"))
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(define+provide (to-string x)
(if (string? x)
x ; fast exit for strings
(with-handlers ([exn:fail? (λ(exn) (error (format "Pollen parser: can't convert ~v to ~a" x 'string)))])
(cond
[(equal? '() x) ""]
[(symbol? x) (symbol->string x)]
[(number? x) (number->string x)]
[(path? x) (path->string x)]
[(char? x) (format "~a" x)]
[else (error)])))) ; put this last so other xexprish things don't get caught
;; decoder wireframe
(define+provide/contract (decode txexpr
#:txexpr-tag-proc [txexpr-tag-proc (λ(x)x)]
#:txexpr-attrs-proc [txexpr-attrs-proc (λ(x)x)]
#:txexpr-elements-proc [txexpr-elements-proc (λ(x)x)]
#:block-txexpr-proc [block-txexpr-proc (λ(x)x)]
#:inline-txexpr-proc [inline-txexpr-proc (λ(x)x)]
#:string-proc [string-proc (λ(x)x)]
#:symbol-proc [symbol-proc (λ(x)x)]
#:valid-char-proc [valid-char-proc (λ(x)x)]
#:cdata-proc [cdata-proc (λ(x)x)]
#:exclude-tags [excluded-tags '()])
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((xexpr/c)
(#:txexpr-tag-proc (txexpr-tag? . -> . txexpr-tag?)
#:txexpr-attrs-proc (txexpr-attrs? . -> . txexpr-attrs?)
#:txexpr-elements-proc (txexpr-elements? . -> . txexpr-elements?)
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#:block-txexpr-proc (block-txexpr? . -> . xexpr?)
#:inline-txexpr-proc (txexpr? . -> . xexpr?)
#:string-proc (string? . -> . xexpr?)
#:symbol-proc (symbol? . -> . xexpr?)
#:valid-char-proc (valid-char? . -> . xexpr?)
#:cdata-proc (cdata? . -> . xexpr?)
#:exclude-tags (listof symbol?) ) . ->* . txexpr?)
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(let loop ([x txexpr])
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(cond
[(txexpr? x) (let-values([(tag attrs elements) (txexpr->values x)])
(if (member tag excluded-tags)
x ; because it's excluded
;; we apply processing here rather than do recursive descent on the pieces
;; because if we send them back through loop, certain element types are ambiguous
;; e.g., ((p "foo")) tests out as both txexpr-attrs and txexpr-elements
(let ([decoded-txexpr
(apply make-txexpr (list (txexpr-tag-proc tag)
(txexpr-attrs-proc attrs)
(map loop (txexpr-elements-proc elements))))])
((if (block-txexpr? decoded-txexpr)
block-txexpr-proc
inline-txexpr-proc) decoded-txexpr))))]
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[(string? x) (string-proc x)]
[(symbol? x) (symbol-proc x)]
[(valid-char? x) (valid-char-proc x)]
[(cdata? x) (cdata-proc x)]
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[else (error "decode: can't decode" x)])))