.. index:: xml .. _xml/0:

.. rst-class:: right

object

`xml`

Bi-directional XML parser.

| Availability: | logtalk_load(xml_parser(loader))

| Author: John Fletcher; adapted to Logtalk by Paulo Moura. | Version: 3:8:4 | Date: 2024-03-14

| Copyright: Copyright (C) 2001-2005 Binding Time Limited, Copyright (C) 2005-2013 John Fletcher | License: This program is offered free of charge, as unsupported source code. You may use it, copy it, distribute it, modify it or sell it without restriction, but entirely at your own risk.

| Compilation flags: | static, context_switching_calls

| Uses: | :ref:`list <list/0>` | :ref:`term <term/0>`

| Remarks:

On-line documentation: https://binding-time.co.uk/index.php/Parsing_XML_with_Prolog
Compliance: This XML parser supports a subset of XML suitable for XML Data and Worldwide Web applications. It is neither as strict nor as comprehensive as the XML 1.0 Specification mandates.
Compliance-strictness: It is not as strict, because, while the specification must eliminate ambiguities, not all errors need to be regarded as faults, and some reasonable examples of real XML usage would have to be rejected if they were.
Compliance-comprehensive: It is not as comprehensive, because, where the XML specification makes provision for more or less complete DTDs to be provided as part of a document, xml.pl actions the local definition of ENTITIES only. Other DTD extensions are treated as commentary.
Bi-directional conversions: Conversions are not fully symmetrical as weaker XML is accepted than can be generated. Notably, in-bound (Codes -> Document) parsing does not require strictly well-formed XML. If Codes does not represent well-formed XML, Document is instantiated to the term malformed(<attributes>,<content>).

| Inherited public predicates: | (none)

.. contents:: :local: :backlinks: top

Public predicates

.. index:: parse/2 .. _xml/0::parse/2:

parse/2 ^^^^^^^^^^^

Parses a list of character codes to/from a data structure of the form xml(<atts>,<content>).

| Compilation flags: | static

.. index:: parse/3 .. _xml/0::parse/3:

parse/3 ^^^^^^^^^^^

Parses a list of character codes to/from a data structure of the form xml(<atts>,<content>) using the given list of options.

| Compilation flags: | static

| Template: | parse(Options,Codes,Document) | Mode and number of proofs: | parse(++list(compound),+list(character_code),?nonvar) - zero_or_one | parse(++list(compound),?list(character_code),+nonvar) - zero_or_one

| Remarks:

extended_characters(Boolean) option: Use the extended character entities for XHTML (default true).
format(Boolean) option: For parsing, strip layouts when no character data appears between elements (default true). For generating, indent the element content (default true).
remove_attribute_prefixes(Boolean) option: Remove namespace prefixes from attributes when it's the same as the prefix of the parent element (default false).
allow_ampersand(Boolean) option: Allow unescaped ampersand characters (&) to occur in PCDATA (default false).

.. index:: subterm/2 .. _xml/0::subterm/2:

subterm/2 ^^^^^^^^^^^^^

Unifies Subterm with a sub-term of XMLTerm. Note that XMLTerm is a sub-term of itself.

| Compilation flags: | static

| Template: | subterm(XMLTerm,Subterm) | Mode and number of proofs: | subterm(+nonvar,?nonvar) - zero_or_one

.. index:: pp/1 .. _xml/0::pp/1:

pp/1 ^^^^^^^^

Pretty prints a XML document on the current output stream.

| Compilation flags: | static

| Template: | pp(XMLDocument) | Mode and number of proofs: | pp(+nonvar) - zero_or_one

Protected predicates

(no local declarations; see entity ancestors if any)

Private predicates

.. index:: xml_to_document/3 .. _xml/0::xml_to_document/3:

xml_to_document/3 ^^^^^^^^^^^^^^^^^^^^^

Translates the list of character codes XML into the Prolog term Document. Options is a list of terms controlling the treatment of layout characters and character entities.

| Compilation flags: | static

| Template: | xml_to_document(Options,XML,Document) | Mode and number of proofs: | xml_to_document(+nonvar,+nonvar,?nonvar) - zero_or_one

.. index:: empty_map/1 .. _xml/0::empty_map/1:

empty_map/1 ^^^^^^^^^^^^^^^

True if Map is a null map.

| Compilation flags: | static

| Template: | empty_map(Map) | Mode and number of proofs: | empty_map(?nonvar) - zero_or_one

.. index:: map_member/3 .. _xml/0::map_member/3:

map_member/3 ^^^^^^^^^^^^^^^^

True if Map is a ordered map structure which records the pair Key-Data. Key must be ground.

| Compilation flags: | static

| Template: | map_member(Key,Map,Data) | Mode and number of proofs: | map_member(+nonvar,+nonvar,?nonvar) - zero_or_one

.. index:: map_store/4 .. _xml/0::map_store/4:

map_store/4 ^^^^^^^^^^^^^^^

True if Map0 is an ordered map structure, Key must be ground, and Map1 is identical to Map0 except that the pair Key-Data is recorded by Map1.

| Compilation flags: | static

| Template: | map_store(Map0,Key,Data,Map1) | Mode and number of proofs: | map_store(+nonvar,+nonvar,+nonvar,?nonvar) - zero_or_one

.. index:: pp_string/1 .. _xml/0::pp_string/1:

pp_string/1 ^^^^^^^^^^^^^^^

Prints String onto the current output stream. If String contains only 7-bit chars it is printed in shorthand quoted format, otherwise it is written as a list.

| Compilation flags: | static

| Template: | pp_string(String) | Mode and number of proofs: | pp_string(+nonvar) - zero_or_one

.. index:: fault/5 .. _xml/0::fault/5:

fault/5 ^^^^^^^^^^^

Identifies SubTerm as a sub-term of Term which cannot be serialized after Indentation. Message is an atom naming the type of error; Path is a string encoding a list of SubTerm's ancestor elements in the form <tag>{(id)}* where <tag> is the element tag and <id> is the value of any attribute named id.

| Compilation flags: | static

| Template: | fault(Term,Indentation,SubTerm,Path,Message) | Mode and number of proofs: | fault(+nonvar,+nonvar,?nonvar,?nonvar,?nonvar) - zero_or_one

.. index:: exception/4 .. _xml/0::exception/4:

exception/4 ^^^^^^^^^^^^^^^

Hook to raise an exception to be raised in respect of a fault in the XML Term Document.

| Compilation flags: | static

| Template: | exception(Message,Document,Culprit,Path) | Mode and number of proofs: | exception(+atom,+nonvar,+nonvar,+nonvar) - one

.. index:: document_generation//2 .. _xml/0::document_generation//2:

document_generation//2 ^^^^^^^^^^^^^^^^^^^^^^^^^^

DCG generating Document as a list of character codes. Format is true|false defining whether layouts, to provide indentation, should be added between the element content of the resultant "string". Note that formatting is disabled for elements that are interspersed with pcdata/1 terms, such as XHTML's 'inline' elements. Also, Format is over-ridden, for an individual element, by an explicit 'xml:space'="preserve" attribute.

| Compilation flags: | static

| Template: | document_generation(Format,Document) | Mode and number of proofs: | document_generation(+nonvar,+nonvar) - zero_or_one

.. index:: pcdata_7bit//1 .. _xml/0::pcdata_7bit//1:

pcdata_7bit//1 ^^^^^^^^^^^^^^^^^^

Represents the ASCII character set in its simplest format, using the character entities &, ", <, and > which are common to both XML and HTML. The numeric entity ' is used in place of ' because browsers don't recognize it in HTML.

| Compilation flags: | static

| Template: | pcdata_7bit(Code) | Mode and number of proofs: | pcdata_7bit(?nonvar) - zero_or_one

.. index:: character_data_format/3 .. _xml/0::character_data_format/3:

character_data_format/3 ^^^^^^^^^^^^^^^^^^^^^^^^^^^

Holds when Format0 and Format1 are the statuses of XML formatting before and after Codes - which may be null.

| Compilation flags: | static

| Template: | character_data_format(Codes,Format0,Format1) | Mode and number of proofs: | character_data_format(+nonvar,+nonvar,?nonvar) - zero_or_one

.. index:: cdata_generation//1 .. _xml/0::cdata_generation//1:

cdata_generation//1 ^^^^^^^^^^^^^^^^^^^^^^^

Holds when Format0 and Format1 are the statuses of XML formatting before and after Codes - which may be null.

| Compilation flags: | static

| Template: | cdata_generation(Codes) | Mode and number of proofs: | cdata_generation(+list) - zero_or_one

Operators

(none)