User "Tim Starling" changed the status of MediaWiki.r81074. Old Status: new New Status: fixme
User "Tim Starling" also posted a comment on MediaWiki.r81074. Full URL: http://www.mediawiki.org/wiki/Special:Code/MediaWiki/81074#c21955 Commit summary: (bug 235) parser function for conversion of units of measurement. [[Template:Convert]] on enwiki is a behemoth of a construction that just about manages to do this sort of conversion, taking {{convert|5|mi|km}} and outputting "5 miles (8 km)", etc. To port this to another wiki requires copying over three and a half thousand subtemplates. The additional load produced by including numerous copies of this template is measurable on large pages on enwiki, and it eats voraciously into the template limits. This revision introduces {{#convert: 5 mi | km }}, outputting "8 km" or thereabouts. See http://www.mediawiki.org/wiki/User:Happy-melon/Convert for more details, or look at the examples in the parser tests. In a very rough profile, comparing 50 calls to {{convert}} verses the same 50 calls to the wrapper template shown at the link above, the parser function implementation reduces page load time by 72%, preprocessor node count by 83%, post-expand include size by 86% and template argument size by 97%. More detailed profiling would probably reveal places where extra caching could improve performance further. The primary reason for putting it in ParserFunctions instead of its own extension is availability: PFs are already available across the cluster, and it's accepted as an essential extension for any wiki wishing to emulate or mirror WMF content. One less separate extension installed on the cluster is one less extension which has to be matched by reusers. It's still missing a lot of units, which I ran out of patience to copy from {{convert}}; I thought I'd get some feedback on the infrastructure first. Comment: Actually the measure of tyre pressure is pounds-force per square inch, not foot-pounds per square inch. See [[w:Pounds per square inch]]. Dimensional analysis is a useful technique, it would have identified your error here. Dimensional analysis can cope with reciprocals. Spelling differences are best dealt with by using abbreviations, which are consistent and international. A style guide I once read recommended that abbreviations should always be used in preference to the unit names, since this convention avoids an unfortunate ambiguity between rad as an abbreviation for radians, and rad the unit name which is abbreviated to rd. Also they are shorter. However <nowiki>{{convert}}</nowiki> on Wikipedia uses full names by default so I suppose we should follow suit here. It seems kind of strange to adopt the spelling conventions for metric units from the most obstinate anti-metric country in the world as our default. The Wikipedia templates do not take this approach, they use the British spelling by default, and allow an "sp=us" parameter to access the American spelling. I suggest adding a method for configuring the language variant to be used on a wiki for unit name display. This would allow the new parser function to match the style used on Wikipedia and avoid the need for #language=en-gb to be added to every invocation. Setting "fixme" status for this feature request. Ideally it should provide a map of base languages to sensible defaults, to provide Wikipedia-like functionality to small wikis without configuration, e.g.: <pre> $wgPFUnitLanguageVariants = array( 'en' => 'en-gb' ); </pre> If $wgContLang is present as a key in the array, the language in the value of that element would be used by default for ConvertParser::$language. _______________________________________________ MediaWiki-CodeReview mailing list mediawiki-coderev...@lists.wikimedia.org https://lists.wikimedia.org/mailman/listinfo/mediawiki-codereview
