Module:Unsubst/sandbox

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Helper module to facilitate a substituted template transform into a template transclusion.

Maintenance templates, such as {{Citation needed}} or {{Refimprove}}, 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:}}}#invoke:Unsubst||$B=

 [ ... existing template code ... ]

}}

The wikitext to display when not substed must be given as "$B". A parameter "$N" may also be seen in some templates; this was required in an older version of the module, but is no longer necessary and may be removed. Such templates are automatically placed in Category:Calls to Module:Unsubst that use $N.

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 }}.

Example

Consider a template Template:Example containing the following code:

{{ {{{|safesubst:}}}#invoke:Unsubst||foo=bar |date=__DATE__ |$B=

 [ ... Template code goes here ... ]

}}

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

The above documentation is transcluded from Module:Unsubst/doc. (edit | history)
Editors can experiment in this module's sandbox (edit | diff) and testcases (create) pages.
Add categories to the /doc subpage. Subpages of this module.

local checkType = require('libraryUtil').checkType

local p = {}

local BODY_PARAM = '$B'

function p.main(frame, body)
	-- If we are substing, 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.

	-- Return the template body if we aren't substing.
	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 invocatoin')
	local name = mTemplateInvocation.name(frame:getParent():getTitle())

	-- Combine passed args with passed defaults, and substitute magic words.
	local args = {}
	for k, v in pairs(frame.args) do
		if k ~= BODY_PARAM 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

	return mTemplateInvocation.invocation(name, args)
end

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

return p