Module:Unsubst

This is a helper module to facilitate a substituted template's transformation into a normal template transclusion.

Maintenance templates, such as {{Citation needed}} or {{More citations needed}}, should never be substituted. A trick to avoid that is to make a template substitute to its transcluded form.

Usage

To turn a template into a self-substituting template, wrap the existing template code with:

{{SAFESUBST:<noinclude />#invoke:Unsubst||$B=

[ … existing template code … ]

}}

The wikitext to display when not substed must be given as $B. All other parameters passed to the #invoke will be copied to the generated template invocation as default values. If the value of any of these default parameters is __DATE__, that value in the generated template invocation will be the current month and year.

Some templates have a <noinclude> but no matching </noinclude> at the end of the template. In such cases, the missing </noinclude> must be added before the ending }}.

Advanced

{{SAFESUBST:<noinclude />#invoke:Unsubst||$params=[ parameters ]|$aliases=[ aliases ]|$flags=[ flags ]|$B=

[ … existing template code … ]

}}

Due to Lua limitations, parameters are normally ordered randomly when the template is substituted. |$params= can be used in #invoke:Unsubst to list template parameters in order, comma-delimited (e.g. egg,bacon,sausage,cheese,spam). Numbered parameters should be before others in the list, then any remaining parameters are tacked onto the end of the generated invocation.

Parameter aliases can be listed in |$aliases= (and shouldn't be listed in |$params=), and will be replaced automatically. Each alias and its replacement should be formatted as alias>replacement, and each of those pairs should be comma-delimited as well (e.g. œuf>egg,melt>cheese). Note that this parameter can function with or without |$params=.

The |$flags= parameter can be used to modify other facets of the module's behaviour, and again, entries are comma-delimited. Valid flags are override (allows parameters in the #invoke: to take precedence over parameters in the original template invocation); keep-whitespace (prevents whitespace from being trimmed from unnamed parameters) and remove-empty (removes empty parameters).

These parameters can be manipulated using parser functions to provide more complicated options (note that in the parameters, any parser function or template or module invocation should also have SAFESUBST:<noinclude />).

Example

Consider a template Template:Example containing the following code:

{{SAFESUBST:<noinclude />#invoke:Unsubst||foo=bar |date=__DATE__ |$B=

[ … Template code goes here … ]

}}

Original	Result
{{subst:example}}	{{Example|date=November 2024}}
{{subst:example|foo=X}}	{{Example|foo=X|date=November 2024}}
{{subst:example|baz=X}}	{{Example|baz=X|date=November 2024}}
{{subst:example|date=January 2001}}	{{Example|foo=bar|date=January 2001}}

---

local checkType = require('libraryUtil').checkType

local p = {}

local BODY_PARAM = '$B'

local specialParams = {
	['$params'] = 'parameter list',
	['$aliases'] = 'parameter aliases',
	['$flags'] = 'flags',
	['$B'] = 'template content',
	['$template-name'] = 'template invocation name override',
}

--[[
If we are subst'ing, this function returns a template invocation, and if not, it
returns the template body. The template body can be specified in the body parameter,
or in the template parameter defined in the BODY_PARAM variable. This function can
be called from Lua or from #invoke.
--]]
function p.main(frame, body)
	-- Return the template body if we aren't subst'ing.
	if not mw.isSubsting() then
		if body ~= nil then
			return body
		elseif frame.args[BODY_PARAM] ~= nil then
			return frame.args[BODY_PARAM]
		else
			error(string.format(
				"no template content specified (use parameter '%s' from #invoke)",
				BODY_PARAM
			), 2)
		end
	end

	-- Sanity check for the frame object.
	if type(frame) ~= 'table'
		or type(frame.getParent) ~= 'function'
		or not frame:getParent()
	then
		error(
			"argument #1 to 'main' must be a frame object with a parent " ..
			"frame available",
			2
		)
	end

	-- Find the invocation name.
	local mTemplateInvocation = require('Module:Template invocation')
	local name

	if frame.args['$template-name'] and '' ~= frame.args['$template-name'] then
		-- Override whatever the template name is with this name.
		name = frame.args['$template-name']
	else
		name = mTemplateInvocation.name(frame:getParent():getTitle())
	end

	-- Combine passed args with passed defaults.
	local args = {}
	if string.find( ','..(frame.args['$flags'] or '')..',', ',%s*override%s*,' ) then
		for k, v in pairs( frame:getParent().args ) do
			args[k] = v
		end
		for k, v in pairs( frame.args ) do
			if not specialParams[k] then
				if v == '__DATE__' then
					v = mw.getContentLanguage():formatDate( 'F Y' )
				end
				args[k] = v
			end
		end
	else
		for k, v in pairs( frame.args ) do
			if not specialParams[k] then
				if v == '__DATE__' then
					v = mw.getContentLanguage():formatDate( 'F Y' )
				end
				args[k] = v
			end
		end
		for k, v in pairs( frame:getParent().args ) do
			args[k] = v
		end
	end

	-- Trim parameters, if not specified otherwise.
	if not string.find( ','..(frame.args['$flags'] or '')..',', ',%s*keep%-whitespace%s*,' ) then
		for k, v in pairs( args ) do args[k] = mw.ustring.match(v, '^%s*(.*)%s*$') or '' end
	end

	-- Pull information from parameter aliases.
	local aliases = {}
	if frame.args['$aliases'] then
		local list = mw.text.split( frame.args['$aliases'], '%s*,%s*' )
		for k, v in ipairs( list ) do
			local tmp = mw.text.split( v, '%s*>%s*' )
			aliases[tonumber(mw.ustring.match(tmp[1], '^[1-9][0-9]*$')) or tmp[1]] = ((tonumber(mw.ustring.match(tmp[2], '^[1-9][0-9]*$'))) or tmp[2])
		end
	end
	for k, v in pairs( aliases ) do
		if args[k] and ( not args[v] or args[v] == '' ) then
			args[v] = args[k]
		end
		args[k] = nil
	end

	-- Remove empty parameters, if specified.
	if string.find( ','..(frame.args['$flags'] or '')..',', ',%s*remove%-empty%s*,' ) then
		local tmp = 0
		for k, v in ipairs( args ) do
			if v ~= '' or ( args[k+1] and args[k+1] ~= '' ) or ( args[k+2] and args[k+2] ~= '' ) then
				tmp = k
			else
				break
			end
		end
		for k, v in pairs( args ) do
			if v == '' then
				if not (type(k) == 'number' and k < tmp) then args[k] = nil end
			end
		end
	end

	-- Order parameters.
	if frame.args['$params'] then
		local params, tmp = mw.text.split( frame.args['$params'], '%s*,%s*' ), {}
		for k, v in ipairs(params) do
			v = tonumber(mw.ustring.match(v, '^[1-9][0-9]*$')) or v
			if args[v] then tmp[v], args[v] = args[v], nil end
		end
		for k, v in pairs(args) do tmp[k], args[k] = args[k], nil end
		args = tmp
	end

	return mTemplateInvocation.invocation(name, args)
end

p[''] = p.main -- For backwards compatibility

return p