Extension:Transliterator

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Transliterator

Release status: beta

Implementation Parser function
Description Allows transliteration of words in entries based on rules in MediaWiki space.
Author(s) Conrad.Irwintalk
Latest version 1.4.1 (23:51, 9 March 2010 (UTC))
MediaWiki only tested with 1.16+
License GPL 3
Download
Parameters

$wgTransliteratorRuleCount = 255; $wgTransliteratorRuleSize = 10;

Hooks used
ParserFirstCallInit

ArticleDeleteComplete
NewRevisionFromEditComplete
ArticlePurge
ArticleUndelete
TitleMoveComplete

Translate the Transliterator extension if it is available at translatewiki.net

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An extension to allow transliteration based on ad-hoc schemes stored in the wiki's MediaWiki space (by default under the [[Mediawiki:Transliterator:]] pseudo-namespace).

Usage on pages[edit | edit source]

Most people will want to use this

{{#transliterate:<mapname>|<word>}}

Which will generate the transliteration of <word> based on the map found in [[MediaWiki:Transliterator:<mapname>]].

Usage in templates[edit | edit source]

Formatting output[edit | edit source]

The extension supports several extra parameters to help template-authors integrate this easily into their code. At a basic level, it allows customisation of the output using the third parameter.

{{#transliterate:<mapname>|<word>| ($1)}}

Will output nothing if there is no page at [[MediaWiki:Transliterator:<mapname>]], or " (<transliteration>)" if the map exists. This should allow template-authors to avoid doing some form of {{#if: statement to see whether a transliteration can be created.

User-supplied transliterations[edit | edit source]

The fourth parameter allows you to set a user-override on the output of a transliteration. This has two uses, one where the transliteration that is generated is incorrect, and two, where the map does not yet exist for a language.

{{#transliterate:<mapname>|<word>| ($1)|{{{tr|}}}}}

Will output  ({{{tr}}}) if {{{tr}}}} is not blank. If {{{tr}}} is blank and [[MediaWiki:Transliterator:<mapname>]] exists, it will output  (<transliteration>) as before. And if {{{tr}}} is blank, and [[MediaWiki:Transliterator:<mapname>]] does not exist, it will output nothing.

Creating maps[edit | edit source]

Simple Overview[edit | edit source]

Every line of the map file should contain a rule like α => a or ae => æ, the longer the rule, the higher its priority. The special characters ^ and $ can be used to match only at the start and end of a word, so ^α => (a or α$ => a). Most of the time the rules are case-insensitive, so if you include π => p, you don't need to include Π => P, however for multiple-character-rules you may need to duplicate them, i.e. ij => kl and IJ => KL are both needed, as the ij => kl provides the automatic rule of Ij => Kl. Lines that start with a # are ignored, and the first line can be __DECOMPOSE__ to use NFD instead of matching letters. CAVEAT: This assumes a word is one or more Unicode characters, and uses the Unicode case-mappings which may not be perfect for all languages.

Syntax[edit | edit source]

Blank lines and lines that start with # are ignored. Other lines should be a rule in the form left-hand-side=>right-hand-side, with the exception of the first one that may contain flags instead of a rule. Whitespace is removed from the beginning and end of lines, and before and after the => symbol, so a => b is exactly equivalent to a=>b.

Transliteration process[edit | edit source]

Rules are applied one-by-one and the next rule starts matching at the character after the previous rule. The rules are matched in length order, so the longest possible rule is used.

  • If the match starts on the start of a word (the previous character wasn't a letter, but this one is) then the rule ^x will match, and take priority over x.
  • If the match ends at the end of a word (this character is a letter, the next one isn't) then the rule x$ will match and take priority over x.
  • If no match is possible, and the first character is upper-case, then it is converted to lower-case, and the longest applicable rule is used.
  • If no rules have matched, and there is no default rule, then one character is passed through unchanged.

Flags[edit | edit source]

The first line of a map can contain:

__DECOMPOSE__
Divides strings into sections using the Unicode form NFD instead of the default letter-based form. This is particularly useful for languages such as Korean, or for situations in which the diacritics in the transliterated form match exactly the diacritics in the original. NOTE: the letter form is not quite NFC as combining diacritics are never split from their base even when there is no pre-combined character for them.

HTML entities[edit | edit source]

The right-hand-side and left-hand-side of rules have HTML entities decoded, this allows for diacritics to be entered in a form that is easy to edit, and for the characters that make up the syntax of the maps to be escaped in the rare cases that you will want to use them. As the HTML entities are also decoded by your web-browser, you will not see a difference unless you edit the page. For example, the HTML entities for "^", "$", ">" and " " are &#x5E;, &#x24;, &gt; and &#x20; (note that the common &nbsp; is not a normal space).

Possible errors[edit | edit source]

All of these error messages appear at the place which {{#transliterate}} is invoked. The maps are not parsed when they are saved.

Ambiguous rule <rule> in [[MediaWiki:Transliterator:<mapname>]]
This is caused when a map contains two rules with the same content on the left of the =>. This can never be correct, as it would leave the Transliterator to make an impossible decision as to which right-hand-side to replace the left-hand-side with.
Invalid syntax <rule> in [[MediaWiki:Transliterator:<mapname>]]
This is caused by a line that contains no "=>" and that does not start with a "#", The parser cannot decide whether you meant it to be a comment, but forgot to say, or whether you meant it to be a rule and got it wrong, so it asks for confirmation.
More than X rules in [[MediaWiki:Transliterator:<mapname>]]
In order that this extension doesn't create massive maps that could potentially consume the server's memory, it limits itself in size. The limit in number of rules is configurable as below. There is no real solution to this problem, unless you work out a better set of rules (with some multi-character sequences there are ways of using the longest-first property to leave out some repetitious rules).
Rule <rule> has more than X characters on the left in [[MediaWiki:Transliterator:<mapname>]]
Due to the algorithm used to transliterate, having long rules on the left both increases the size of the map, and increases the maximum time that may be taken in transliteration. If you find yourself wanting to break this limit, the chances are that your language cannot be transliterated automatically.

Advanced customisation[edit | edit source]

The namespace in which maps are put is set by the magic word 'tr_prefix', in English it is 'Transliterator:', but locales may customise this.

The global variable $wgTransliteratorRuleCount, by default 255, specifies the maximum number of entries in a mapping; while $wgTransliteratorRuleSize, by default 10, specifies the maximum length of the left hand side of the rule. These are totally arbitrary limits, and it may be the case that different bounds work better for you. You should set the configuration variables after requiring extensions/Transliterator/Transliterator.php as otherwise they will be overwritten by the defaults.