DOC: convert library(sgml) documentation to DocLog format
Predicates for parsing HTML and XML documents.
Written 2020-2022 by Markus Triska (triska@metalevel.at)
Part of Scryer Prolog.
+- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
+
+/** Predicates for parsing HTML and XML documents.
Currently, two predicates are provided:
- - load_html(+Source, -Es, +Options)
- - load_xml(+Source, -Es, +Options)
+ - `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.
+ - `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.
+
+ * `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.
+`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!".
+Yielding `T = "Hello!"`.
- Use http_open/3 from library(http/http_open) to read answers from
+Use `http_open/3` from `library(http/http_open)` to read answers from
web servers via streams.
-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
+*/
:- module(sgml, [load_html/3,
load_xml/3]).
