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Common attributes parser code module, for use by Plugins authors.

Summary of Contents

Provides a simple and consistent interface for creation and management of lists of standard TWiki-syntax attribute value lists, as used in tags.

Detailed Documentation

Package TWiki::Contrib::Attrs

Class of attribute sets, designed for parsing and storing attribute values from a TWiki tag e.g. %TAG{fred="bad" "sad" joe="mad"}%

An attribute set is a map containing an entry for each parameter. The default parameter (unnamed quoted string) is named __default__ in the map. Attributes declared later in the string will override those of the same name defined earlier. Escaping quotes is not supported.

The parser is forgiving; it will handle standard TWiki syntax (parameter values double-quoted) but also single-quoted values, unquoted spaceless values, spaces around the =, and commas as well as spaces separating values.

new ($string, $friendly) => \%attrsObjectRef

  • $string - String containing attribute specification
  • $friendly - if true, the parse will be according to the extended syntax pioneered by the original Contrib::Attrs. Otherwise it will be strict as per traditional TWiki syntax.

Parse a standard attribute string containing name=value pairs and create a new attributes object. The value may be a word or a quoted string. If there is an error during parsing, the parse will complete but $attrs->{_ERROR} will be set in the new object.

Extended syntax example:

use TWiki::Contrib::Attrs;
my $attrs = new TWiki::Contrib::Attrs('the="time \\"has come", "the walrus" said to=speak of=\'many \\'things\', 1);
In this example:
  • the will be time "has come
  • __default__ will be the walrus
  • said will be on
  • to will be speak
  • of will be many 'things

Only " and ' are escaped.

Traditional syntax is as old TWiki, except that the whole string is parsed (the old parser would only recognise default values in position 1, nowhere else)

get( $key) => value

$key Attribute name
Get an attr value; return undef if not set

isEmpty() => boolean

Return false if attribute set is not empty.

remove($key) => value

$key Attribute to remove
Remove an attr value from the map, return old value. After a call to remove the attribute is no longer defined.

toString() => string

Generate a printed form for the map, using standard attribute syntax, with only the single-quote extension syntax observed (no {} brackets, though).


  • Name of the perl package
    • Set STUB = TWiki::Contrib::Attrs

Installation Instructions

  • Download the ZIP file from the Plugin web (see below)
  • Unzip in your twiki installation directory. Content:
    File: Description:

Plugin Info

Author: TWiki:Main/CrawfordCurrie
Copyright ©: 2001, Motorola Corp, All Rights Reserved
License: GPL
Dependencies: None
Change History:  
14/08/04 Separated out from SharedCode? module

Related Topics: TWikiPreferences

-- TWiki:Main/CrawfordCurrie - 12:53:50 16 August 2004

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