Module:User

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Revision as of 14:18, 6 April 2014 by blackwiki>Mr. Stradivarius (deal with nil values properly)
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This module implements {{user}}. For documentation, please see the template page.

Technical details

While the {{user}} template is only a wrapper for Module:UserLinks, by implementing it as a Lua module we make significant gains in performance. It is roughly twice as fast as accessing Module:UserLinks from wikitext. For example, this module rendered a test page containing nothing but 1000 {{user}} transclusions in 3.9 seconds, whereas the version that called Module:UserLinks from wikitext rendered it in 7.7 seconds.

The performance gains are achieved by reducing the number of parameters that are looked up from wikitext. In particular, the link codes, "t" and "c", along with the "span=no" option, are passed directly to UserLinks. Also, UserLinks looks up the arguments "user", "User", "project", "Project", "lang", and "Lang". From wikitext, each parameter is checked twice – once for the #invoke text and once for the calling template – and each check is relatively resource-heavy. From Lua, each parameter is only checked once, and the individual checks take much less time. This means that on average, maybe nine argument lookups are saved in each invocation by using this module. On pages with hundreds or thousands of invocations, this adds up to a lot of argument lookups saved.



local mUserLinks = require('Module:UserLinks')
local mShared = require('Module:UserLinks/shared')
local yesno = require('Module:Yesno')

local p = {}

local function validateArg(arg)
	if not arg then
		return nil
	end
	arg = arg:match('^%s*(.-)%s*$')
	if arg ~= '' then
		return arg
	end
end

function p.main(frame)
	local argKeys = {
		user = {
			1,
			'User',
			'user'
		},
		project = {
			2,
			'Project',
			'project'
		},
		lang = {
			3,
			'Lang',
			'lang'
		}
	}
	local origArgs = frame:getParent().args
	local args = {}
	for argKey, t in pairs(argKeys) do
		for i, origArgKey in ipairs(t) do
			local value = origArgs[origArgKey]
			value = validateArg(value)
			if value then
				args[argKey] = value
				break
			end
		end
	end
	local options = {
		span = false,
		separator = validateArg(origArgs.separator) or 'dot',
		isDemo = yesno(validateArg(origArgs.demo))
	}
	local codes = {'t', 'c'}
	local snippets = userLinks.getSnippets(args)
	local links = userLinks.getLinks(snippets)
	local success, result = pcall(mUserLinks.export, codes, links, options)
	if success then
		return result
	else
		return mShared.makeWikitextError(result, options.isDemo)
	end
end

return p