Module:Template parameter value

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Implements {{Template parameter value}} and {{HasTemplate}}, and can be used from other modules.

Module functions

getParameter

getParameter takes 4 arguments: The page name (string), the template/s (string or table of strings), the parameter (string), and an optional options table. It will return either true and the contents of the requested parameter or false and a reason for failure.

The following options are available:

• template_index: Which occurrence of the template to look for the parameter in. Set to -1 for last occurrence. (default: 1)
• parameter_index: Which occurrence of the parameter to look for (default: 1; only applies when ignore_subtemplates is false)
• ignore_subtemplates: If parameters should only be searched for in the top-level template, ignoring the parameters in subtemplates (default: false)
• only_subtemplates: If parameters should only be searched for in subtemplates of the top-level template (default: false)
• ignore_blank: Whether or not blank values should count towards parameter_index (default: false)
• treat_as_regex: Whether or not the template string(s) should be treated as a lua regex (default: false)

getTemplate

getTemplate takes 3 arguments: The page name (string), the template/s (string or table of strings), and an optional options table. It will return either true and the text of the requested template or false and a reason for failure.

getTemplate supports the options template_index and treat_as_regex from getParameter.

Helper functions

The module exposes some of the helper functions used (matchAllTemplates, getParameters, and getAllParameters) for convenience. Each function has some comments above it in the code explaining its rough purpose.

Template functions

main implements {{Template parameter value}} and acts as a template wrapper for getParameter.

hasTemplate implements {{HasTemplate}} and somewhat acts as a wrapper for getTemplate (it only provides if the template was found, not the template text itself).

Testcases

Testcases are available at Module talk:Template parameter value/testcases

The above documentation is transcluded from Module:Template parameter value/doc. (edit | history)
Editors can experiment in this module's sandbox (edit | diff) and testcases (edit | run) pages.
Subpages of this module.

local p = {}
local escape = require("Module:String")._escapePattern
function trimspaces(s)
	return string.gsub(s, "^%s*(.-)%s*$", "%1")
end

local function getTitle(title)
	local success, titleObj = pcall(mw.title.new, title)
	if success then return titleObj
	else return nil end
end

function p.main(frame)
	local args = require('Module:Arguments').getArgs(frame, {
		wrappers = 'Template:Template parameter value'
	})
	local template = escape(args[2])
	local parameter = escape(args[4])
	local numberedParameter = (tonumber(parameter) ~= nil)
	
	local templateCount = 0
	local parameterCount = 0
	local templateMatch = tonumber(args[3] or 1)
	local parameterMatch = tonumber(args[5] or 1)*(numberedParameter and parameter or 1)
	
	local targettitle = getTitle(args[1])
	if targettitle == nil then return "" end
    local content = string.gsub(targettitle:getContent() or "", "[\r\n]", "")
	
	while templateCount ~= templateMatch do
		if content == nil then return "" end
		content = string.match(content, '{{' .. template .. "(.+)")
		templateCount = templateCount + 1
	end
	
	while parameterCount ~= parameterMatch do
		if content == nil then return "" end
		content, content_rest = string.match(content, '|%s*' .. (numberedParameter and "" or (parameter .. '%s*=%s*')) .. '([^|]*)(.*)')
		while string.match(content, '^[^%]]*%[%[[^%]]+$') or string.match(content, '^[^%}]*%{%{[^%}]+$') do
			content_match, content_rest = string.match(content_rest, '(.[^|]*)(.*)')
			content = content .. content_match
		end
		parameterCount = parameterCount + 1
	end
	content = string.match(content, '^([^%{]*)%}%}') or content
	content = string.match(content, '^(.+)%{%{[^%}]*$') or content
	
	local _, countL = string.gsub(content, "%{%{", "")
	local _, countR = string.gsub(content, "%}%}", "")
	local countDiff = math.abs(countL-countR)
	while countDiff > 0 do
		content = string.match(content, '^(.*)%}%}$') or content
		countDiff = countDiff - 1
	end
	
	if content == nil then return "" end
	
	content = string.gsub(content, "</?%a*include%a*>", "")
	content = string.gsub(content, "^%d+=", "")
	content = frame:preprocess{text = content}
	content = trimspaces(content)
	
	return content
end

return p