DOC: convert library(sgml) documentation to DocLog format

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Markus Triska
2023-01-24 22:42:58 +01:00
parent 26d39c3617
commit af9f0f81d8

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@@ -2,57 +2,70 @@
Predicates for parsing HTML and XML documents.
Written 2020-2022 by Markus Triska (triska@metalevel.at)
Part of Scryer Prolog.
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.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
/** 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.
*/
:- module(sgml, [load_html/3,
load_xml/3]).