►HTML: Parsing Library
read-xhtml
read-html
read-html-as-xml
read-html-comments
use-html-spec
1 Example
2 HTML Structures
html-element
html-full
html
div
center
blockquote
ins
del
dd
li
th
td
iframe
noframes
noscript
style
script
basefont
br
area
alink
img
param
hr
input
col
isindex
base
meta
option
textarea
title
head
tr
colgroup
thead
tfoot
tbody
tt
i
b
u
s
strike
big
small
em
strong
dfn
code
samp
kbd
var
cite
abbr
acronym
sub
sup
span
bdo
font
p
h1
h2
h3
h4
h5
h6
q
dt
legend
caption
table
button
fieldset
optgroup
select
label
form
ol
ul
dir
menu
dl
pre
object
applet
map
a
address
body
Version: 5.1
  top← prev  up  next → 

HTML: Parsing Library

 (require html)
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/c)
  port : input-port?
Reads HTML from a port, producing an X-expression compatible with the xml library (which defines content/c).

(read-html-comments) → boolean?
(read-html-comments v) → void?
  v : any/c
If v is not #f, then comments are read and returned. Defaults to #f.

(use-html-spec) → boolean?
(use-html-spec v) → void?
  v : any/c
If v is not #f, then the HTML must respect the HTML specification with regards to what elements are allowed to be the children of other elements. For example, the top-level "<html>" element may only contain a "<body>" and "<head>" element. Defaults to #f.

1 Example

  (module html-example racket
  
    ; Some of the symbols in html and xml conflict with
    ; each other and with racket/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 (attributes 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)
  #:extra-constructor-name make-html-element)
  attributes : (listof attribute)
Any of the structures below inherits from html-element.

(struct html-full struct:html-element (content)
  #:extra-constructor-name make-html-full)
  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 ()
  #:extra-constructor-name make-html)
A html is (make-html (listof attribute) (listof Contents-of-html))

A Contents-of-html is either

(struct div html-full ()
  #:extra-constructor-name make-div)
A div is (make-div (listof attribute) (listof G2))

(struct center html-full ()
  #:extra-constructor-name make-center)
A center is (make-center (listof attribute) (listof G2))

(struct blockquote html-full ()
  #:extra-constructor-name make-blockquote)
A blockquote is (make-blockquote (listof attribute) G2)

(struct ins html-full ()
  #:extra-constructor-name make-ins)
An Ins is (make-ins (listof attribute) (listof G2))

(struct del html-full ()
  #:extra-constructor-name make-del)
A del is (make-del (listof attribute) (listof G2))

(struct dd html-full ()
  #:extra-constructor-name make-dd)
A dd is (make-dd (listof attribute) (listof G2))

(struct li html-full ()
  #:extra-constructor-name make-li)
A li is (make-li (listof attribute) (listof G2))

(struct th html-full ()
  #:extra-constructor-name make-th)
A th is (make-th (listof attribute) (listof G2))

(struct td html-full ()
  #:extra-constructor-name make-td)
A td is (make-td (listof attribute) (listof G2))

(struct iframe html-full ()
  #:extra-constructor-name make-iframe)
An iframe is (make-iframe (listof attribute) (listof G2))

(struct noframes html-full ()
  #:extra-constructor-name make-noframes)
A noframes is (make-noframes (listof attribute) (listof G2))

(struct noscript html-full ()
  #:extra-constructor-name make-noscript)
A noscript is (make-noscript (listof attribute) (listof G2))

(struct style html-full ()
  #:extra-constructor-name make-style)
A style is (make-style (listof attribute) (listof pcdata))

(struct script html-full ()
  #:extra-constructor-name make-script)
A script is (make-script (listof attribute) (listof pcdata))

(struct basefont html-element ()
  #:extra-constructor-name make-basefont)
A basefont is (make-basefont (listof attribute))

(struct br html-element ()
  #:extra-constructor-name make-br)
A br is (make-br (listof attribute))

(struct area html-element ()
  #:extra-constructor-name make-area)
An area is (make-area (listof attribute))

(struct alink html-element ()
  #:extra-constructor-name make-alink)
A alink is (make-alink (listof attribute))

(struct img html-element ()
  #:extra-constructor-name make-img)
An img is (make-img (listof attribute))

(struct param html-element ()
  #:extra-constructor-name make-param)
A param is (make-param (listof attribute))

(struct hr html-element ()
  #:extra-constructor-name make-hr)
A hr is (make-hr (listof attribute))

(struct input html-element ()
  #:extra-constructor-name make-input)
An input is (make-input (listof attribute))

(struct col html-element ()
  #:extra-constructor-name make-col)
A col is (make-col (listof attribute))

(struct isindex html-element ()
  #:extra-constructor-name make-isindex)
An isindex is (make-isindex (listof attribute))

(struct base html-element ()
  #:extra-constructor-name make-base)
A base is (make-base (listof attribute))

(struct meta html-element ()
  #:extra-constructor-name make-meta)
A meta is (make-meta (listof attribute))

(struct option html-full ()
  #:extra-constructor-name make-option)
An option is (make-option (listof attribute) (listof pcdata))

(struct textarea html-full ()
  #:extra-constructor-name make-textarea)
A textarea is (make-textarea (listof attribute) (listof pcdata))

(struct title html-full ()
  #:extra-constructor-name make-title)
A title is (make-title (listof attribute) (listof pcdata))

(struct head html-full ()
  #:extra-constructor-name make-head)
A head is (make-head (listof attribute) (listof Contents-of-head))

A Contents-of-head is either

(struct tr html-full ()
  #:extra-constructor-name make-tr)
A tr is (make-tr (listof attribute) (listof Contents-of-tr))

A Contents-of-tr is either

(struct colgroup html-full ()
  #:extra-constructor-name make-colgroup)
A colgroup is (make-colgroup (listof attribute) (listof col))

(struct thead html-full ()
  #:extra-constructor-name make-thead)
A thead is (make-thead (listof attribute) (listof tr))

(struct tfoot html-full ()
  #:extra-constructor-name make-tfoot)
A tfoot is (make-tfoot (listof attribute) (listof tr))

(struct tbody html-full ()
  #:extra-constructor-name make-tbody)
A tbody is (make-tbody (listof attribute) (listof tr))

(struct tt html-full ()
  #:extra-constructor-name make-tt)
A tt is (make-tt (listof attribute) (listof G5))

(struct i html-full ()
  #:extra-constructor-name make-i)
An i is (make-i (listof attribute) (listof G5))

(struct b html-full ()
  #:extra-constructor-name make-b)
A b is (make-b (listof attribute) (listof G5))

(struct u html-full ()
  #:extra-constructor-name make-u)
An u is (make-u (listof attribute) (listof G5))

(struct s html-full ()
  #:extra-constructor-name make-s)
A s is (make-s (listof attribute) (listof G5))

(struct strike html-full ()
  #:extra-constructor-name make-strike)
A strike is (make-strike (listof attribute) (listof G5))

(struct big html-full ()
  #:extra-constructor-name make-big)
A big is (make-big (listof attribute) (listof G5))

(struct small html-full ()
  #:extra-constructor-name make-small)
A small is (make-small (listof attribute) (listof G5))

(struct em html-full ()
  #:extra-constructor-name make-em)
An em is (make-em (listof attribute) (listof G5))

(struct strong html-full ()
  #:extra-constructor-name make-strong)
A strong is (make-strong (listof attribute) (listof G5))

(struct dfn html-full ()
  #:extra-constructor-name make-dfn)
A dfn is (make-dfn (listof attribute) (listof G5))

(struct code html-full ()
  #:extra-constructor-name make-code)
A code is (make-code (listof attribute) (listof G5))

(struct samp html-full ()
  #:extra-constructor-name make-samp)
A samp is (make-samp (listof attribute) (listof G5))

(struct kbd html-full ()
  #:extra-constructor-name make-kbd)
A kbd is (make-kbd (listof attribute) (listof G5))

(struct var html-full ()
  #:extra-constructor-name make-var)
A var is (make-var (listof attribute) (listof G5))

(struct cite html-full ()
  #:extra-constructor-name make-cite)
A cite is (make-cite (listof attribute) (listof G5))

(struct abbr html-full ()
  #:extra-constructor-name make-abbr)
An abbr is (make-abbr (listof attribute) (listof G5))

(struct acronym html-full ()
  #:extra-constructor-name make-acronym)
An acronym is (make-acronym (listof attribute) (listof G5))

(struct sub html-full ()
  #:extra-constructor-name make-sub)
A sub is (make-sub (listof attribute) (listof G5))

(struct sup html-full ()
  #:extra-constructor-name make-sup)
A sup is (make-sup (listof attribute) (listof G5))

(struct span html-full ()
  #:extra-constructor-name make-span)
A span is (make-span (listof attribute) (listof G5))

(struct bdo html-full ()
  #:extra-constructor-name make-bdo)
A bdo is (make-bdo (listof attribute) (listof G5))

(struct font html-full ()
  #:extra-constructor-name make-font)
A font is (make-font (listof attribute) (listof G5))

(struct p html-full ()
  #:extra-constructor-name make-p)
A p is (make-p (listof attribute) (listof G5))

(struct h1 html-full ()
  #:extra-constructor-name make-h1)
A h1 is (make-h1 (listof attribute) (listof G5))

(struct h2 html-full ()
  #:extra-constructor-name make-h2)
A h2 is (make-h2 (listof attribute) (listof G5))

(struct h3 html-full ()
  #:extra-constructor-name make-h3)
A h3 is (make-h3 (listof attribute) (listof G5))

(struct h4 html-full ()
  #:extra-constructor-name make-h4)
A h4 is (make-h4 (listof attribute) (listof G5))

(struct h5 html-full ()
  #:extra-constructor-name make-h5)
A h5 is (make-h5 (listof attribute) (listof G5))

(struct h6 html-full ()
  #:extra-constructor-name make-h6)
A h6 is (make-h6 (listof attribute) (listof G5))

(struct q html-full ()
  #:extra-constructor-name make-q)
A q is (make-q (listof attribute) (listof G5))

(struct dt html-full ()
  #:extra-constructor-name make-dt)
A dt is (make-dt (listof attribute) (listof G5))

(struct legend html-full ()
  #:extra-constructor-name make-legend)
A legend is (make-legend (listof attribute) (listof G5))

(struct caption html-full ()
  #:extra-constructor-name make-caption)
A caption is (make-caption (listof attribute) (listof G5))

(struct table html-full ()
  #:extra-constructor-name make-table)
A table is (make-table (listof attribute) (listof Contents-of-table))

A Contents-of-table is either

(struct button html-full ()
  #:extra-constructor-name make-button)
A button is (make-button (listof attribute) (listof G4))

(struct fieldset html-full ()
  #:extra-constructor-name make-fieldset)
A fieldset is (make-fieldset (listof attribute) (listof Contents-of-fieldset))

A Contents-of-fieldset is either

(struct optgroup html-full ()
  #:extra-constructor-name make-optgroup)
An optgroup is (make-optgroup (listof attribute) (listof option))

(struct select html-full ()
  #:extra-constructor-name make-select)
A select is (make-select (listof attribute) (listof Contents-of-select))

A Contents-of-select is either

(struct label html-full ()
  #:extra-constructor-name make-label)
A label is (make-label (listof attribute) (listof G6))

(struct form html-full ()
  #:extra-constructor-name make-form)
A form is (make-form (listof attribute) (listof G3))

(struct ol html-full ()
  #:extra-constructor-name make-ol)
An ol is (make-ol (listof attribute) (listof li))

(struct ul html-full ()
  #:extra-constructor-name make-ul)
An ul is (make-ul (listof attribute) (listof li))

(struct dir html-full ()
  #:extra-constructor-name make-dir)
A dir is (make-dir (listof attribute) (listof li))

(struct menu html-full ()
  #:extra-constructor-name make-menu)
A menu is (make-menu (listof attribute) (listof li))

(struct dl html-full ()
  #:extra-constructor-name make-dl)
A dl is (make-dl (listof attribute) (listof Contents-of-dl))

A Contents-of-dl is either

(struct pre html-full ()
  #:extra-constructor-name make-pre)
A pre is (make-pre (listof attribute) (listof Contents-of-pre))

A Contents-of-pre is either

  • G9

  • G11

(struct object html-full ()
  #:extra-constructor-name make-object)
An object is (make-object (listof attribute) (listof Contents-of-object-applet))

(struct applet html-full ()
  #:extra-constructor-name make-applet)
An applet is (make-applet (listof attribute) (listof Contents-of-object-applet))

A Contents-of-object-applet is either

(struct map html-full ()
  #:extra-constructor-name make-map)
A Map is (make-map (listof attribute) (listof Contents-of-map))

A Contents-of-map is either

(struct a html-full ()
  #:extra-constructor-name make-a)
An a is (make-a (listof attribute) (listof Contents-of-a))

A Contents-of-a is either

(struct address html-full ()
  #:extra-constructor-name make-address)
An address is (make-address (listof attribute) (listof Contents-of-address))

A Contents-of-address is either

(struct body html-full ()
  #:extra-constructor-name make-body)
A body is (make-body (listof attribute) (listof Contents-of-body))

A Contents-of-body is either

A G12 is either

A G11 is either

A G10 is either

A G9 is either

A G8 is either

A G7 is either

  • G8

  • G12

A G6 is either

A G5 is either

A G4 is either

  • G8

  • G10

A G3 is either

A G2 is either

  top← prev  up  next →