Module sgml

:- use_module(library(sgml)).

Predicates for parsing HTML and XML documents.

Currently, two predicates are provided:

load_html(+Source, -Es, +Options)
load_xml(+Source, -Es, +Options)

These predicates parse HTML and XML documents, respectively.

Source must be one of:

a list of characters with the document contents
stream(S), specifying a stream S from which to read the content
file(Name), where Name is a list of characters specifying a file name.

Es is unified with the abstract syntax tree of the parsed document, represented as a list of elements where each is of the form:

a list of characters, representing text
element(Name, Attrs, Children)
- Name, an atom, is the name of the tag
- Attrs is a list of Key=Value pairs: Key is an atom, and Value is a list of characters
- Children is a list of elements as specified here.

Currently, Options are ignored. In the future, more options may be provided to control parsing.

Example:


   ?- load_html("<html><head><title>Hello!</title></head></html>", Es, []).

Yielding:


      Es = [element(html,[],
             [element(head,[],
               [element(title,[],
                 ["Hello!"])]),
              element(body,[],[])])].

library(xpath) provides convenient reasoning about parsed documents. For example, to fetch the title of the document above, we can use:


   ?- load_html("<html><head><title>Hello!</title></head></html>", Es, []),
      xpath(Es, //title(text), T).

Yielding T = "Hello!".

Use http_open/3 from library(http/http_open) to read answers from web servers via streams.

Browse source code

Module sgml

load_html/3

load_xml/3