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reduce dependencies

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dev-fixit v0.2
Matthew Butterick 9 years ago
parent 3a6bb6b343
commit f06acaf169
4 changed files with 400 additions and 385 deletions
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349
base.rkt
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#lang racket/base
(require sugar/define sugar/coerce sugar/list racket/string racket/list racket/match xml rackunit)
(provide cdata? cdata valid-char? xexpr->string xexpr?) ; from xml
(provide empty) ; from racket/list
;; Section 2.2 of XML 1.1
;; (XML 1.0 is slightly different and more restrictive)
;; make private version of my-valid-char to get consistent results with Racket 6.0
(define (my-valid-char? i)
(and (exact-nonnegative-integer? i)
(or (<= #x1 i #xD7FF)
(<= #xE000 i #xFFFD)
(<= #x10000 i #x10FFFF))))
(define (my-xexpr? x)
(or (txexpr? x) (xexpr? x) (my-valid-char? x)))
(define+provide+safe (txexpr? x #:short-only? [short-only #f])
predicate/c
(define short-sym 'short)
(and (pair? x)
(txexpr-tag? (car x))
(let ([result (or (and (empty? (cdr x)) short-sym)
;; separate the my-xexpr? tail match from the rest.
;; as a recursive operation, it's potentially time-consuming.
(and (andmap my-xexpr? (cddr x))
(match (cadr x)
[(list (? txexpr-attr?) ...) #t]
[(? my-xexpr?) short-sym]
[else #f])))])
(and result (if short-only
(eq? result short-sym)
#t)))))
(define+provide+safe (txexpr-short? x)
predicate/c
(txexpr? x #:short-only? #t))
(define+provide+safe (txexpr-tag? x)
predicate/c
(symbol? x))
(define+provide+safe (txexpr-tags? x)
predicate/c
(and (list? x) (andmap txexpr-tag? x)))
(define+provide+safe (txexpr-attr? x)
predicate/c
(match x
[(list (? symbol?) (? string?)) #t]
[else #f]))
(define+provide+safe (txexpr-element? x)
predicate/c
(my-xexpr? x))
(define+provide+safe (txexpr-attr-key? x)
predicate/c
(symbol? x))
(define+provide+safe (can-be-txexpr-attr-key? x)
predicate/c
(or (symbol? x) (string? x)))
(define+provide+safe (txexpr-attr-value? x)
predicate/c
(string? x))
(define+provide+safe (can-be-txexpr-attr-value? x)
predicate/c
(or (symbol? x) (string? x)))
(define-syntax-rule (define-plural plural-id pred)
(define+provide+safe (plural-id x)
predicate/c
(and (list? x) (andmap pred x))))
(define-plural txexpr-attrs? txexpr-attr?)
(define-plural txexpr-elements? txexpr-element?)
(define-plural txexpr-attr-values? txexpr-attr-value?)
(define-plural list-of-can-be-txexpr-attrs? can-be-txexpr-attrs?)
(define+provide+safe (can-be-txexpr-attrs? x)
predicate/c
(ormap (λ(test) (test x)) (list txexpr-attr?
txexpr-attrs?
can-be-txexpr-attr-key?
can-be-txexpr-attr-value?)))
(define (validate-txexpr-attrs x #:context [txexpr-context #f])
(define (make-reason)
(if (not (list? x))
(format "because ~v is not a list" x)
(let ([bad-attrs (filter (λ(i) (not (txexpr-attr? i))) x)])
(format "because ~a ~a" (string-join (map (λ(ba) (format "~v" ba)) bad-attrs) " and ")
(if (> (length bad-attrs) 1)
"are not valid attributes"
"is not in the form '(symbol \"string\")")))))
(cond
[(and (list? x) (> (length x) 0) (andmap txexpr-attr? x)) x]
[else (error (string-append "validate-txexpr-attrs: "
(if txexpr-context (format "in ~v, " txexpr-context) "")
(format "~v is not a valid list of attributes ~a" x
(make-reason))))]))
(define (validate-txexpr-element x #:context [txexpr-context #f])
(cond
[(or (string? x) (txexpr? x) (symbol? x)
(valid-char? x) (cdata? x)) x]
[else (error (string-append "validate-txexpr-element: "
(if txexpr-context (format "in ~v, " txexpr-context) "")
(format "~v is not a valid element (must be txexpr, string, symbol, XML char, or cdata)" x)))]))
;; is it a named x-expression?
;; todo: rewrite this recurively so errors can be pinpointed (for debugging)
(define+provide+safe (validate-txexpr x)
(any/c . -> . txexpr?)
(define-syntax-rule (validate-txexpr-attrs-with-context e)
(validate-txexpr-attrs e #:context x))
(define-syntax-rule (validate-txexpr-element-with-context e)
(validate-txexpr-element e #:context x))
(cond
[(txexpr-short? x) x]
[(txexpr? x) (and
(validate-txexpr-attrs-with-context (get-attrs x))
(andmap (λ(e) (validate-txexpr-element-with-context e)) (get-elements x)) x)]
[(and (list? x) (symbol? (car x)))
(and
(andmap (λ(e) (validate-txexpr-element-with-context e)) (get-elements x))
(validate-txexpr-attrs-with-context (get-attrs x)))]
[(list? x) (error 'validate-txexpr (format "~v is a list but it doesn't start with a symbol" x))]
[else (error 'validate-txexpr (format "~v: not an X-expression" x))]))
(define+provide+safe (txexpr tag [attrs null] [elements null])
((symbol?) (txexpr-attrs? txexpr-elements?) . ->* . txexpr?)
(define result (cons tag (append (if (empty? attrs) empty (list attrs)) elements)))
(if (txexpr? result)
result
(error 'txexpr
(cond
[(not (txexpr-tag? tag))
(format "This is not a txexpr-tag: ~v" tag)]
[(not (txexpr-attrs? attrs))
(format "This is not a list of txexpr-attrs: ~v" attrs)]
[(not (txexpr-elements? elements))
(format "This is not a list of txexpr-elements: ~v" elements)]
[else ""]))))
(define make-txexpr txexpr) ; for backward compatability
(provide+safe make-txexpr)
(define+provide+safe (txexpr->values x)
(txexpr? . -> . (values symbol? txexpr-attrs? txexpr-elements?))
(if (txexpr-short? x)
(values (car x) '() (cdr x))
(values (car x) (cadr x) (cddr x))))
(define+provide+safe (txexpr->list x)
(txexpr? . -> . list?)
(define-values (tag attrs content) (txexpr->values x))
(list tag attrs content))
;; convenience functions to retrieve only one part of txexpr
(define+provide+safe (get-tag x)
(txexpr? . -> . txexpr-tag?)
(car x))
(define+provide+safe (get-attrs x)
(txexpr? . -> . txexpr-attrs?)
(define-values (tag attrs content) (txexpr->values x))
attrs)
(define+provide+safe (get-elements x)
(txexpr? . -> . txexpr-elements?)
(define-values (tag attrs elements) (txexpr->values x))
elements)
;; helpers. we are getting a string or symbol
(define+provide+safe (->txexpr-attr-key x)
(can-be-txexpr-attr-key? . -> . txexpr-attr-key?)
(->symbol x))
(define+provide+safe (->txexpr-attr-value x)
(can-be-txexpr-attr-value? . -> . txexpr-attr-value?)
(->string x))
(define identity (λ (x) x))
(define+provide+safe (attrs->hash #:hash-style? [hash-style-priority #f] . items-in)
(() (#:hash-style? boolean?) #:rest (listof can-be-txexpr-attrs?) . ->* . hash-eq?)
;; can be liberal with input because they're all just nested key/value pairs
;; but still need this function to make sure that 'foo and "foo" are treated as the same hash key
(define items (flatten items-in))
(unless (even? (length items))
(raise-argument-error 'attrs->hash "even number of arguments" items-in))
;; hasheq loop will overwrite earlier values with later.
;; but earlier attributes need priority (see https://www.w3.org/TR/xml/#attdecls)
;; thus reverse the pairs.
;; priority-inverted will defeat this assumption, and allow later attributes to overwrite earlier.
(for/hasheq ([sublist (in-list ((if hash-style-priority
identity
reverse) (slice-at items 2)))])
(let ([key (->txexpr-attr-key (first sublist))]
[value (->txexpr-attr-value (second sublist))])
(values key value))))
(define+provide+safe (hash->attrs attr-hash)
(hash? . -> . txexpr-attrs?)
(map flatten (hash->list attr-hash)))
(define+provide+safe (attrs-have-key? x key)
((or/c txexpr-attrs? txexpr?) can-be-txexpr-attr-key? . -> . boolean?)
(define attrs (if (txexpr-attrs? x) x (get-attrs x)))
(and (assq (->txexpr-attr-key key) attrs) #t))
(define+provide+safe (attr-set tx key value)
(txexpr? can-be-txexpr-attr-key? can-be-txexpr-attr-value? . -> . txexpr?)
(attr-set* tx key value))
(define+provide+safe (attr-set* tx . kvs)
((txexpr?) #:rest (listof (or/c can-be-txexpr-attr-key? can-be-txexpr-attr-value?)) . ->* . txexpr?)
;; unlike others, this uses hash operations to guarantee that your attr-set
;; is the only one remaining.
(unless (even? (length kvs))
(raise-argument-error 'attr-set* "even number of arguments" kvs))
(define new-attrs
(hash->attrs
(apply hash-set* (attrs->hash (get-attrs tx))
(append-map (λ(sublist)
(list (->txexpr-attr-key (first sublist))
(->txexpr-attr-value (second sublist)))) (slice-at kvs 2)))))
(txexpr (get-tag tx) new-attrs (get-elements tx)))
(define+provide+safe (attr-join tx key value)
(txexpr? can-be-txexpr-attr-key? can-be-txexpr-attr-value? . -> . txexpr?)
(define starting-values (string-split (if (attrs-have-key? tx key)
(attr-ref tx key)
"")))
(attr-set tx key (string-join `(,@starting-values ,value) " ")))
(define+provide+safe (attr-ref tx key [failure-result (λ _ (raise (make-exn:fail:contract (format "attr-ref: no value found for key ~v" key) (current-continuation-marks))))])
((txexpr? can-be-txexpr-attr-key?) (any/c) . ->* . any)
(define result (assq (->txexpr-attr-key key) (get-attrs tx)))
(if result
(second result)
(if (procedure? failure-result)
(failure-result)
failure-result)))
(define+provide+safe (remove-attrs x)
(txexpr? . -> . txexpr?)
(let loop ([x x])
(if (txexpr? x)
(let-values ([(tag attr elements) (txexpr->values x)])
(txexpr tag null (map loop elements)))
x)))
(define+provide+safe (map-elements proc x)
(procedure? txexpr? . -> . txexpr?)
(proc (if (txexpr? x)
(let-values ([(tag attr elements) (txexpr->values x)])
(txexpr tag attr (map (λ(e)(map-elements proc e)) elements)))
x)))
;; function to split tag out of txexpr
(define deleted-signal (gensym))
(define+provide+safe (splitf-txexpr tx pred [proc (λ(x) deleted-signal)])
((txexpr? procedure?) (procedure?) . ->* . (values txexpr? txexpr-elements?))
(define matches null)
(define (do-extraction x)
(cond
[(pred x) (begin ; store matched item and return processed value
(set! matches (cons x matches))
(proc x))]
[(txexpr? x) (let-values([(tag attr elements) (txexpr->values x)])
(txexpr tag attr (filter (λ(e) (not (equal? e deleted-signal)))
(map do-extraction elements))))]
[else x]))
(define tx-extracted (do-extraction tx)) ;; do this first to fill matches
(unless (txexpr? tx-extracted)
(error 'splitf-txexpr "Bad input"))
(values tx-extracted (reverse matches)))
(define+provide+safe (findf*-txexpr tx pred)
(txexpr? procedure? . -> . (or/c #f txexpr-elements?))
(define-values (_ matches) (splitf-txexpr tx pred))
(and (pair? matches) matches))
(define+provide+safe (findf-txexpr tx pred)
(txexpr? procedure? . -> . (or/c #f txexpr-element?))
(define matches (findf*-txexpr tx pred))
(and matches (car matches)))
(define+provide+safe (xexpr->html x)
(xexpr? . -> . string?)
(define (->cdata x)
(cond
[(cdata? x) x]
; don't use "![CDATA[...]]" wrapper in HTML, it's not consistent with the spec
[(string? x) (cdata #f #f x)]
[else x]))
(xexpr->string (let loop ([x x])
(cond
[(txexpr? x) (if (member (get-tag x) '(script style))
(txexpr (get-tag x) (get-attrs x)
(map ->cdata (get-elements x)))
(txexpr (get-tag x) (get-attrs x)
(map loop (get-elements x))))]
[else x]))))

38
check.rkt
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#lang racket/base
(require sugar/define "base.rkt" rackunit)
(define (txexprs-equal? tx1 tx2)
;; txexprs are deemed equal if they differ only in the ordering of attributes.
;; therefore, to check them, 1) sort their attributes, 2) straight list comparison.
;; use letrec because `define-simple-check` wants an expression in <=6.2
;; `stringify-attr` is needed because comparing attr keys won't work if there are two attrs with same key.
;; so the whole attr is converted into a single string for sorting, which lets the attr value act as a tiebreaker.
;; it doesn't matter that this sort may not be correct (in the sense of a desirable ordering)
;; it just needs to be stable (e.g., a certain set of attrs will always sort the same way)
(letrec ([stringify-attr (λ(attr) (string-append (symbol->string (car attr)) (cadr attr)))]
[sort-attrs (λ(x)
(if (txexpr? x)
(let-values ([(tag attr elements) (txexpr->values x)])
(txexpr tag (sort attr #:key stringify-attr #:cache-keys? #t string<?) (map sort-attrs elements)))
x))])
(equal? (sort-attrs tx1) (sort-attrs tx2))))
(define+provide+safe (attrs-equal? x1 x2)
((or/c txexpr-attrs? txexpr?) (or/c txexpr-attrs? txexpr?) . -> . boolean?)
(define attrs-tx1 (if (txexpr-attrs? x1) x1 (get-attrs x1)))
(define attrs-tx2 (if (txexpr-attrs? x2) x2 (get-attrs x2)))
(txexprs-equal? `(div ,attrs-tx1) `(div ,attrs-tx2)))
(provide+safe check-txexprs-equal?)
(define-simple-check (check-txexprs-equal? tx1 tx2)
(txexprs-equal? tx1 tx2))
(module+ test
(check-txexprs-equal? '(p ((b "foo")(a "bar")) (span ((d "foo")(c "bar"))))
'(p ((a "bar")(b "foo")) (span ((c "bar")(d "foo")))))
;; two attrs with same key
(check-txexprs-equal? '(p ((a "foo")(a "bar")))
'(p ((a "bar")(a "foo")))))

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info.rkt
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#lang info #lang info
(define version "0.1") (define version "0.2")
(define collection "txexpr") (define collection "txexpr")
(define deps '("base" "sugar" "rackunit-lib")) (define deps '("base" ["sugar" #:version "0.2"] "rackunit-lib"))
(define update-implies '("sugar")) (define update-implies '("sugar"))
(define build-deps '("scribble-lib" "racket-doc" "rackunit-doc")) (define build-deps '("scribble-lib" "racket-doc" "rackunit-doc"))
(define scribblings '(("scribblings/txexpr.scrbl" ()))) (define scribblings '(("scribblings/txexpr.scrbl" ())))

394
main.rkt
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#lang racket/base #lang racket/base
(require sugar/define sugar/coerce sugar/list racket/string racket/list racket/match xml rackunit)
(provide cdata? cdata valid-char? xexpr->string xexpr?) ; from xml
(provide empty) ; from racket/list
;; Section 2.2 of XML 1.1 (define-syntax-rule (r+p modname ...)
;; (XML 1.0 is slightly different and more restrictive) (begin
;; make private version of my-valid-char to get consistent results with Racket 6.0 (begin
(define (my-valid-char? i) (require modname)
(and (exact-nonnegative-integer? i) (provide (all-from-out modname))
(or (<= #x1 i #xD7FF) (module+ safe
(<= #xE000 i #xFFFD) (require (submod modname safe))
(<= #x10000 i #x10FFFF)))) (provide (all-from-out (submod modname safe))))) ...))
(r+p "base.rkt"
(define (my-xexpr? x) "check.rkt")
(or (txexpr? x) (xexpr? x) (my-valid-char? x)))
(define+provide+safe (txexpr? x #:short-only? [short-only #f])
predicate/c
(define short-sym 'short)
(and (pair? x)
(txexpr-tag? (car x))
(let ([result (or (and (empty? (cdr x)) short-sym)
;; separate the my-xexpr? tail match from the rest.
;; as a recursive operation, it's potentially time-consuming.
(and (andmap my-xexpr? (cddr x))
(match (cadr x)
[(list (? txexpr-attr?) ...) #t]
[(? my-xexpr?) short-sym]
[else #f])))])
(and result (if short-only
(eq? result short-sym)
#t)))))
(define+provide+safe (txexpr-short? x)
predicate/c
(txexpr? x #:short-only? #t))
(define+provide+safe (txexpr-tag? x)
predicate/c
(symbol? x))
(define+provide+safe (txexpr-tags? x)
predicate/c
(and (list? x) (andmap txexpr-tag? x)))
(define+provide+safe (txexpr-attr? x)
predicate/c
(match x
[(list (? symbol?) (? string?)) #t]
[else #f]))
(define+provide+safe (txexpr-element? x)
predicate/c
(my-xexpr? x))
(define+provide+safe (txexpr-attr-key? x)
predicate/c
(symbol? x))
(define+provide+safe (can-be-txexpr-attr-key? x)
predicate/c
(or (symbol? x) (string? x)))
(define+provide+safe (txexpr-attr-value? x)
predicate/c
(string? x))
(define+provide+safe (can-be-txexpr-attr-value? x)
predicate/c
(or (symbol? x) (string? x)))
(define-syntax-rule (define-plural plural-id pred)
(define+provide+safe (plural-id x)
predicate/c
(and (list? x) (andmap pred x))))
(define-plural txexpr-attrs? txexpr-attr?)
(define-plural txexpr-elements? txexpr-element?)
(define-plural txexpr-attr-values? txexpr-attr-value?)
(define-plural list-of-can-be-txexpr-attrs? can-be-txexpr-attrs?)
(define+provide+safe (can-be-txexpr-attrs? x)
predicate/c
(ormap (λ(test) (test x)) (list txexpr-attr?
txexpr-attrs?
can-be-txexpr-attr-key?
can-be-txexpr-attr-value?)))
(define (validate-txexpr-attrs x #:context [txexpr-context #f])
(define (make-reason)
(if (not (list? x))
(format "because ~v is not a list" x)
(let ([bad-attrs (filter (λ(i) (not (txexpr-attr? i))) x)])
(format "because ~a ~a" (string-join (map (λ(ba) (format "~v" ba)) bad-attrs) " and ")
(if (> (length bad-attrs) 1)
"are not valid attributes"
"is not in the form '(symbol \"string\")")))))
(cond
[(and (list? x) (> (length x) 0) (andmap txexpr-attr? x)) x]
[else (error (string-append "validate-txexpr-attrs: "
(if txexpr-context (format "in ~v, " txexpr-context) "")
(format "~v is not a valid list of attributes ~a" x
(make-reason))))]))
(define (validate-txexpr-element x #:context [txexpr-context #f])
(cond
[(or (string? x) (txexpr? x) (symbol? x)
(valid-char? x) (cdata? x)) x]
[else (error (string-append "validate-txexpr-element: "
(if txexpr-context (format "in ~v, " txexpr-context) "")
(format "~v is not a valid element (must be txexpr, string, symbol, XML char, or cdata)" x)))]))
;; is it a named x-expression?
;; todo: rewrite this recurively so errors can be pinpointed (for debugging)
(define+provide+safe (validate-txexpr x)
(any/c . -> . txexpr?)
(define-syntax-rule (validate-txexpr-attrs-with-context e)
(validate-txexpr-attrs e #:context x))
(define-syntax-rule (validate-txexpr-element-with-context e)
(validate-txexpr-element e #:context x))
(cond
[(txexpr-short? x) x]
[(txexpr? x) (and
(validate-txexpr-attrs-with-context (get-attrs x))
(andmap (λ(e) (validate-txexpr-element-with-context e)) (get-elements x)) x)]
[(and (list? x) (symbol? (car x)))
(and
(andmap (λ(e) (validate-txexpr-element-with-context e)) (get-elements x))
(validate-txexpr-attrs-with-context (get-attrs x)))]
[(list? x) (error 'validate-txexpr (format "~v is a list but it doesn't start with a symbol" x))]
[else (error 'validate-txexpr (format "~v: not an X-expression" x))]))
(define+provide+safe (txexpr tag [attrs null] [elements null])
((symbol?) (txexpr-attrs? txexpr-elements?) . ->* . txexpr?)
(define result (cons tag (append (if (empty? attrs) empty (list attrs)) elements)))
(if (txexpr? result)
result
(error 'txexpr
(cond
[(not (txexpr-tag? tag))
(format "This is not a txexpr-tag: ~v" tag)]
[(not (txexpr-attrs? attrs))
(format "This is not a list of txexpr-attrs: ~v" attrs)]
[(not (txexpr-elements? elements))
(format "This is not a list of txexpr-elements: ~v" elements)]
[else ""]))))
(define make-txexpr txexpr) ; for backward compatability
(provide+safe make-txexpr)
(define+provide+safe (txexpr->values x)
(txexpr? . -> . (values symbol? txexpr-attrs? txexpr-elements?))
(if (txexpr-short? x)
(values (car x) '() (cdr x))
(values (car x) (cadr x) (cddr x))))
(define+provide+safe (txexpr->list x)
(txexpr? . -> . list?)
(define-values (tag attrs content) (txexpr->values x))
(list tag attrs content))
;; convenience functions to retrieve only one part of txexpr
(define+provide+safe (get-tag x)
(txexpr? . -> . txexpr-tag?)
(car x))
(define+provide+safe (get-attrs x)
(txexpr? . -> . txexpr-attrs?)
(define-values (tag attrs content) (txexpr->values x))
attrs)
(define+provide+safe (get-elements x)
(txexpr? . -> . txexpr-elements?)
(define-values (tag attrs elements) (txexpr->values x))
elements)
;; helpers. we are getting a string or symbol
(define+provide+safe (->txexpr-attr-key x)
(can-be-txexpr-attr-key? . -> . txexpr-attr-key?)
(->symbol x))
(define+provide+safe (->txexpr-attr-value x)
(can-be-txexpr-attr-value? . -> . txexpr-attr-value?)
(->string x))
(define identity (λ (x) x))
(define+provide+safe (attrs->hash #:hash-style? [hash-style-priority #f] . items-in)
(() (#:hash-style? boolean?) #:rest (listof can-be-txexpr-attrs?) . ->* . hash-eq?)
;; can be liberal with input because they're all just nested key/value pairs
;; but still need this function to make sure that 'foo and "foo" are treated as the same hash key
(define items (flatten items-in))
(unless (even? (length items))
(raise-argument-error 'attrs->hash "even number of arguments" items-in))
;; hasheq loop will overwrite earlier values with later.
;; but earlier attributes need priority (see https://www.w3.org/TR/xml/#attdecls)
;; thus reverse the pairs.
;; priority-inverted will defeat this assumption, and allow later attributes to overwrite earlier.
(for/hasheq ([sublist (in-list ((if hash-style-priority
identity
reverse) (slice-at items 2)))])
(let ([key (->txexpr-attr-key (first sublist))]
[value (->txexpr-attr-value (second sublist))])
(values key value))))
(define+provide+safe (hash->attrs attr-hash)
(hash? . -> . txexpr-attrs?)
(map flatten (hash->list attr-hash)))
(define+provide+safe (attrs-have-key? x key)
((or/c txexpr-attrs? txexpr?) can-be-txexpr-attr-key? . -> . boolean?)
(define attrs (if (txexpr-attrs? x) x (get-attrs x)))
(and (assq (->txexpr-attr-key key) attrs) #t))
(define+provide+safe (attr-set tx key value)
(txexpr? can-be-txexpr-attr-key? can-be-txexpr-attr-value? . -> . txexpr?)
(attr-set* tx key value))
(define+provide+safe (attr-set* tx . kvs)
((txexpr?) #:rest (listof (or/c can-be-txexpr-attr-key? can-be-txexpr-attr-value?)) . ->* . txexpr?)
;; unlike others, this uses hash operations to guarantee that your attr-set
;; is the only one remaining.
(unless (even? (length kvs))
(raise-argument-error 'attr-set* "even number of arguments" kvs))
(define new-attrs
(hash->attrs
(apply hash-set* (attrs->hash (get-attrs tx))
(append-map (λ(sublist)
(list (->txexpr-attr-key (first sublist))
(->txexpr-attr-value (second sublist)))) (slice-at kvs 2)))))
(txexpr (get-tag tx) new-attrs (get-elements tx)))
(define+provide+safe (attr-join tx key value)
(txexpr? can-be-txexpr-attr-key? can-be-txexpr-attr-value? . -> . txexpr?)
(define starting-values (string-split (if (attrs-have-key? tx key)
(attr-ref tx key)
"")))
(attr-set tx key (string-join `(,@starting-values ,value) " ")))
(define+provide+safe (attr-ref tx key [failure-result (λ _ (raise (make-exn:fail:contract (format "attr-ref: no value found for key ~v" key) (current-continuation-marks))))])
((txexpr? can-be-txexpr-attr-key?) (any/c) . ->* . any)
(define result (assq (->txexpr-attr-key key) (get-attrs tx)))
(if result
(second result)
(if (procedure? failure-result)
(failure-result)
failure-result)))
(define+provide+safe (remove-attrs x)
(txexpr? . -> . txexpr?)
(let loop ([x x])
(if (txexpr? x)
(let-values ([(tag attr elements) (txexpr->values x)])
(txexpr tag null (map loop elements)))
x)))
(define+provide+safe (map-elements proc x)
(procedure? txexpr? . -> . txexpr?)
(proc (if (txexpr? x)
(let-values ([(tag attr elements) (txexpr->values x)])
(txexpr tag attr (map (λ(e)(map-elements proc e)) elements)))
x)))
;; function to split tag out of txexpr
(define deleted-signal (gensym))
(define+provide+safe (splitf-txexpr tx pred [proc (λ(x) deleted-signal)])
((txexpr? procedure?) (procedure?) . ->* . (values txexpr? txexpr-elements?))
(define matches null)
(define (do-extraction x)
(cond
[(pred x) (begin ; store matched item and return processed value
(set! matches (cons x matches))
(proc x))]
[(txexpr? x) (let-values([(tag attr elements) (txexpr->values x)])
(txexpr tag attr (filter (λ(e) (not (equal? e deleted-signal)))
(map do-extraction elements))))]
[else x]))
(define tx-extracted (do-extraction tx)) ;; do this first to fill matches
(unless (txexpr? tx-extracted)
(error 'splitf-txexpr "Bad input"))
(values tx-extracted (reverse matches)))
(define+provide+safe (findf*-txexpr tx pred)
(txexpr? procedure? . -> . (or/c #f txexpr-elements?))
(define-values (_ matches) (splitf-txexpr tx pred))
(and (pair? matches) matches))
(define+provide+safe (findf-txexpr tx pred)
(txexpr? procedure? . -> . (or/c #f txexpr-element?))
(define matches (findf*-txexpr tx pred))
(and matches (car matches)))
(define+provide+safe (xexpr->html x)
(xexpr? . -> . string?)
(define (->cdata x)
(cond
[(cdata? x) x]
; don't use "![CDATA[...]]" wrapper in HTML, it's not consistent with the spec
[(string? x) (cdata #f #f x)]
[else x]))
(xexpr->string (let loop ([x x])
(cond
[(txexpr? x) (if (member (get-tag x) '(script style))
(txexpr (get-tag x) (get-attrs x)
(map ->cdata (get-elements x)))
(txexpr (get-tag x) (get-attrs x)
(map loop (get-elements x))))]
[else x]))))
(define (txexprs-equal? tx1 tx2)
;; txexprs are deemed equal if they differ only in the ordering of attributes.
;; therefore, to check them, 1) sort their attributes, 2) straight list comparison.
;; use letrec because `define-simple-check` wants an expression in <=6.2
;; `stringify-attr` is needed because comparing attr keys won't work if there are two attrs with same key.
;; so the whole attr is converted into a single string for sorting, which lets the attr value act as a tiebreaker.
;; it doesn't matter that this sort may not be correct (in the sense of a desirable ordering)
;; it just needs to be stable (e.g., a certain set of attrs will always sort the same way)
(letrec ([stringify-attr (λ(attr) (string-append (symbol->string (car attr)) (cadr attr)))]
[sort-attrs (λ(x)
(if (txexpr? x)
(let-values ([(tag attr elements) (txexpr->values x)])
(txexpr tag (sort attr #:key stringify-attr #:cache-keys? #t string<?) (map sort-attrs elements)))
x))])
(equal? (sort-attrs tx1) (sort-attrs tx2))))
(define+provide+safe (attrs-equal? x1 x2)
((or/c txexpr-attrs? txexpr?) (or/c txexpr-attrs? txexpr?) . -> . boolean?)
(define attrs-tx1 (if (txexpr-attrs? x1) x1 (get-attrs x1)))
(define attrs-tx2 (if (txexpr-attrs? x2) x2 (get-attrs x2)))
(txexprs-equal? `(div ,attrs-tx1) `(div ,attrs-tx2)))
(provide+safe check-txexprs-equal?)
(define-simple-check (check-txexprs-equal? tx1 tx2)
(txexprs-equal? tx1 tx2))
(module+ test
(check-txexprs-equal? '(p ((b "foo")(a "bar")) (span ((d "foo")(c "bar"))))
'(p ((a "bar")(b "foo")) (span ((c "bar")(d "foo")))))
;; two attrs with same key
(check-txexprs-equal? '(p ((a "foo")(a "bar")))
'(p ((a "bar")(a "foo")))))
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