HTML: Parsing Library

Version: 4.1.0.2

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HTML: Parsing Library

The html library provides functions to read html documents and structures to represent them.

(read-xhtml port) → html?
port : input-port?
(read-html port) → html?
port : input-port?

Reads (X)HTML from a port, producing an html instance.

(read-html-as-xml port) → (listof content?)
port : input-port?

Reads HTML from a port, producing an xexpr compatible with the xml library (which defines content?).

1 Example

  (module html-example scheme

    ; Some of the symbols in html and xml conflict with
    ; each other and with scheme/base language, so we prefix
    ; to avoid namespace conflict.
    (require (prefix-in h: html)
             (prefix-in x: xml))

    (define an-html
      (h:read-xhtml
       (open-input-string
        (string-append
         "<html><head><title>My title</title></head><body>"
         "<p>Hello world</p><p><b>Testing</b>!</p>"
         "</body></html>"))))

    ; extract-pcdata: html-content -> (listof string)
    ; Pulls out the pcdata strings from some-content.
    (define (extract-pcdata some-content)
      (cond [(x:pcdata? some-content)
             (list (x:pcdata-string some-content))]
            [(x:entity? some-content)
             (list)]
            [else
             (extract-pcdata-from-element some-content)]))

    ; extract-pcdata-from-element: html-element -> (listof string)
    ; Pulls out the pcdata strings from an-html-element.
    (define (extract-pcdata-from-element an-html-element)
      (match an-html-element
        [(struct h:html-full (content))
         (apply append (map extract-pcdata content))]

        [(struct h:html-element (attributes))
         '()]))

    (printf "~s~n" (extract-pcdata an-html)))

> (require 'html-example)
("My title" "Hello world" "Testing" "!")

2 HTML Structures

pcdata, entity, and attribute are defined in the xml documentation.

A html-content is either

(struct

html-element

(attributes))
attributes : (listof attribute)

Any of the structures below inherits from html-element.

(struct

(html-full struct:html-element)

(content))
content : (listof html-content)

Any html tag that may include content also inherits from html-full without adding any additional fields.

(struct

(html html-full)

())

A html is (make-html (listof attribute) (listof Contents-of-html))

A Contents-of-html is either

(struct

(div html-full)

())

A div is (make-div (listof attribute) (listof G2))

(struct

(center html-full)

())

A center is (make-center (listof attribute) (listof G2))

(struct

(blockquote html-full)

())

A blockquote is (make-blockquote (listof attribute) G2)

(struct

(ins html-full)

())

An Ins is (make-ins (listof attribute) (listof G2))

(struct

(del html-full)

())

A del is (make-del (listof attribute) (listof G2))

(struct

(dd html-full)

())

A dd is (make-dd (listof attribute) (listof G2))

(struct

(li html-full)

())

A li is (make-li (listof attribute) (listof G2))

(struct

(th html-full)

())

A th is (make-th (listof attribute) (listof G2))

(struct

(td html-full)

())

A td is (make-td (listof attribute) (listof G2))

(struct

(iframe html-full)

())

An iframe is (make-iframe (listof attribute) (listof G2))

(struct

(noframes html-full)

())

A noframes is (make-noframes (listof attribute) (listof G2))

(struct

(noscript html-full)

())

A noscript is (make-noscript (listof attribute) (listof G2))

(struct

(style html-full)

())

A style is (make-style (listof attribute) (listof pcdata))

(struct

(script html-full)

())

A script is (make-script (listof attribute) (listof pcdata))

(struct

(basefont html-element)

())

A basefont is (make-basefont (listof attribute))

(struct

(br html-element)

())

A br is (make-br (listof attribute))

(struct

(area html-element)

())

An area is (make-area (listof attribute))

(struct

(alink html-element)

())

A alink is (make-alink (listof attribute))

(struct

(img html-element)

())

An img is (make-img (listof attribute))

(struct

(param html-element)

())

A param is (make-param (listof attribute))

(struct

(hr html-element)

())

A hr is (make-hr (listof attribute))

(struct

(input html-element)

())

An input is (make-input (listof attribute))

(struct

(col html-element)

())

A col is (make-col (listof attribute))

(struct

(isindex html-element)

())

An isindex is (make-isindex (listof attribute))

(struct

(base html-element)

())

A base is (make-base (listof attribute))

(struct

(meta html-element)

())

A meta is (make-meta (listof attribute))

(struct

(option html-full)

())

An option is (make-option (listof attribute) (listof pcdata))

(struct

(textarea html-full)

())

A textarea is (make-textarea (listof attribute) (listof pcdata))

(struct

(title html-full)

())

A title is (make-title (listof attribute) (listof pcdata))

(struct

(head html-full)

())

A head is (make-head (listof attribute) (listof Contents-of-head))

A Contents-of-head is either

(struct

(tr html-full)

())

A tr is (make-tr (listof attribute) (listof Contents-of-tr))

A Contents-of-tr is either

td
th

(struct

(colgroup html-full)

())

A colgroup is (make-colgroup (listof attribute) (listof col))

(struct

(thead html-full)

())

A thead is (make-thead (listof attribute) (listof tr))

(struct

(tfoot html-full)

())

A tfoot is (make-tfoot (listof attribute) (listof tr))

(struct

(tbody html-full)

())

A tbody is (make-tbody (listof attribute) (listof tr))

(struct

(tt html-full)

())

A tt is (make-tt (listof attribute) (listof G5))

(struct

(i html-full)

())

An i is (make-i (listof attribute) (listof G5))

(struct

(b html-full)

())

A b is (make-b (listof attribute) (listof G5))

(struct

(u html-full)

())

An u is (make-u (listof attribute) (listof G5))

(struct

(s html-full)

())

A s is (make-s (listof attribute) (listof G5))

(struct

(strike