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add #:exclude-attrs to `decode`

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pull/58/head
Matthew Butterick 10 years ago
parent bb072a8a9a
commit 96785afac5
2 changed files with 27 additions and 14 deletions
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17
decode.rkt
Unescape Escape View File

@ -32,7 +32,8 @@
#: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 '()])
#:exclude-tags [excluded-tags '()]
#:exclude-attrs [excluded-attrs '()])
((xexpr/c)
(#:txexpr-tag-proc (txexpr-tag? . -> . txexpr-tag?)
#:txexpr-attrs-proc (txexpr-attrs? . -> . txexpr-attrs?)
@ -43,13 +44,14 @@
#:symbol-proc (symbol? . -> . xexpr?)
#:valid-char-proc (valid-char? . -> . xexpr?)
#:cdata-proc (cdata? . -> . xexpr?)
#:exclude-tags symbols?) . ->* . txexpr?)
#:exclude-tags (listof txexpr-tag?)
#:exclude-attrs txexpr-attrs?) . ->* . txexpr?)
(let loop ([x txexpr])
(cond
[(txexpr? x) (let-values([(tag attrs elements) (txexpr->values x)])
(if (member tag excluded-tags)
(if (or (member tag excluded-tags) (ormap (λ(attr) (member attr excluded-attrs)) attrs))
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
@ -78,7 +80,8 @@
#: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 '()])
#:exclude-tags [excluded-tags '()]
#:exclude-attrs [excluded-attrs '()])
((txexpr-elements?)
(#:txexpr-tag-proc (txexpr-tag? . -> . txexpr-tag?)
#:txexpr-attrs-proc (txexpr-attrs? . -> . txexpr-attrs?)
@ -89,7 +92,8 @@
#:symbol-proc (symbol? . -> . xexpr?)
#:valid-char-proc (valid-char? . -> . xexpr?)
#:cdata-proc (cdata? . -> . xexpr?)
#:exclude-tags symbols?) . ->* . txexpr-elements?)
#:exclude-tags (listof txexpr-tag?)
#:exclude-attrs txexpr-attrs?) . ->* . txexpr-elements?)
(define temp-tag (gensym "temp-tag"))
(define decode-result (decode `(temp-tag ,@elements)
@ -102,7 +106,8 @@
#:symbol-proc symbol-proc
#:valid-char-proc valid-char-proc
#:cdata-proc cdata-proc
#:exclude-tags excluded-tags))
#:exclude-tags excluded-tags
#:exclude-attrs excluded-attrs))
(get-elements decode-result))

24
scribblings/decode.scrbl
Unescape Escape View File

@ -34,7 +34,8 @@ Another example is conversion of output into a particular data format. Most Poll
[#:symbol-proc symbol-proc (symbol? . -> . xexpr?) (λ(sym) sym)]
[#:valid-char-proc valid-char-proc (valid-char? . -> . xexpr?) (λ(vc) vc)]
[#:cdata-proc cdata-proc (cdata? . -> . xexpr?) (λ(cdata) cdata)]
[#:exclude-tags tags-to-exclude (listof symbol?) null]
[#:exclude-tags tags-to-exclude (listof txexpr-tag?) null]
[#:exclude-attrs attrs-to-exclude txexpr-attrs? null]
)
txexpr?]
Recursively process a @racket[_tagged-xexpr], usually the one exported from a Pollen source file as @racket[doc].
@ -156,12 +157,12 @@ The @racket[_string-proc], @racket[_symbol-proc], @racket[_valid-char-proc], and
Finally, the @racket[_tags-to-exclude] argument is a list of tags that will be exempted from decoding. Though you could get the same result by testing the input within the individual decoding functions, that's tedious and potentially slower.
The @racket[_tags-to-exclude] argument is a list of tags that will be exempted from decoding. Though you could get the same result by testing the input within the individual decoding functions, that's tedious and potentially slower.
@examples[#:eval my-eval
(define tx '(p "I really think" (em "italics") "should be lowercase."))
(decode tx #:string-proc (λ(s) (string-upcase s)))
(decode tx #:string-proc (λ(s) (string-upcase s)) #:exclude-tags '(em))
(decode tx #:string-proc string-upcase)
(decode tx #:string-proc string-upcase #:exclude-tags '(em))
]
The @racket[_tags-to-exclude] argument is useful if you're decoding source that's destined to become HTML. According to the HTML spec, material within a @racket[<style>] or @racket[<script>] block needs to be preserved literally. In this example, if the CSS and JavaScript blocks are capitalized, they won't work. So exclude @racket['(style script)], and problem solved.
@ -170,11 +171,17 @@ The @racket[_tags-to-exclude] argument is useful if you're decoding source that'
(define tx '(body (h1 [[class "Red"]] "Let's visit Planet Telex.")
(style [[type "text/css"]] ".Red {color: green;}")
(script [[type "text/javascript"]] "var area = h * w;")))
(decode tx #:string-proc (λ(s) (string-upcase s)))
(decode tx #:string-proc (λ(s) (string-upcase s))
#:exclude-tags '(style script))
(decode tx #:string-proc string-upcase)
(decode tx #:string-proc string-upcase #:exclude-tags '(style script))
]
Finally, the @racket[_attrs-to-exclude] argument works the same way as @racket[_tags-to-exclude], but instead of excluding an element based on its tag, it excludes based on whether the element has a matching attribute/value pair.
@examples[#:eval my-eval
(define tx '(p (span "No attrs") (span ((id "foo")) "One attr")))
(decode tx #:string-proc string-upcase)
(decode tx #:string-proc string-upcase #:exclude-attrs '((id "foo")))
]
@defproc[
(decode-elements
@ -188,7 +195,8 @@ The @racket[_tags-to-exclude] argument is useful if you're decoding source that'
[#:symbol-proc symbol-proc (symbol? . -> . xexpr?) (λ(sym) sym)]
[#:valid-char-proc valid-char-proc (valid-char? . -> . xexpr?) (λ(vc) vc)]
[#:cdata-proc cdata-proc (cdata? . -> . xexpr?) (λ(cdata) cdata)]
[#:exclude-tags tags-to-exclude (listof symbol?) null]
[#:exclude-tags tags-to-exclude (listof txexpr-tag?) null]
[#:exclude-attrs attrs-to-exclude txexpr-attrs? null]
)
txexpr-elements?]
Identical to @racket[decode], but takes @racket[txexpr-elements?] as input rather than a whole tagged X-expression, and likewise returns @racket[txexpr-elements?] rather than a tagged X-expression. A convenience variant for use inside tag functions.

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