Module:Unsubst
Helper module to facilitate a substituted template transform into a template transclusion.
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 but no matching at the end of the template. In such cases the missing 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. |$params= can be used in #invoke:Unsubst to list template parameters in order, comma‐separated (e.g. egg,bacon,sausage,cheese,spam). Numbered parameters should be before others on the list. Any remaining parameters are tacked onto the end of the generated invocation.
Parameter aliases can be listed in |$aliases= (and shouldn’t be listed in |$params=), and will be replaced automatically. Each alias and its replacement should be formatted as alias>replacement, and each of those pairs should be comma‐separated (e.g. œuf>egg,melt>cheese). Note that this parameter can function with or without |$params=.
Parameter |$flags= can be used to modify other facets of the module’s behaviour; entries are comma‐separated. Valid flags are override (allows parameters in the #invoke: to take precedence over parameters in the original template invocation); keep-whitespace (prevents whitespace from being trimmed from unnamed parameters); and remove-empty (removes empty parameters).
These parameters can be manipulated using parser functions to provide more complicated options (note that in the parameters any parser function, or template or module invocation, should also have SAFESUBST:<noinclude />).
Example
Consider a template Template:Example containing the following code:
{{SAFESUBST:<noinclude />#invoke:Unsubst||foo=bar |date=__DATE__ |$B=
[ ... Template code goes here ... ]
}}
| Original | Result |
|---|---|
{{subst|example}}
|
{{Example|foo=bar|date=April 2024}}
|
{{subst|example|foo=X}}
|
{{Example|foo=X|date=April 2024}}
|
{{subst|example|baz=X}}
|
{{Example|baz=X|date=April 2024}}
|
{{subst|example|date=January 2001}}
|
{{Example|foo=bar|date=January 2001}}
|
local p = {}
local specialParams = {
['$N'] = 'template name', -- Deprecated, but keeping until it is removed from transcluding templates
['$B'] = 'template content',
}
p[''] = function ( frame )
if not frame:getParent() then
error( '{{#invoke:Unsubst|}} makes no sense without a parent frame' )
end
if not frame.args['$B'] then
error( '{{#invoke:Unsubst|}} requires parameter $B (template content)' )
end
if mw.isSubsting() then
---- substing
-- Combine passed args with passed defaults
local args = {}
for k, v in pairs( frame.args ) do
if not specialParams[k] then
if v == '__DATE__' then
v = mw.getContentLanguage():formatDate( 'F Y' )
end
args[k] = v
end
end
for k, v in pairs( frame:getParent().args ) do
args[k] = v
end
-- Build an equivalent template invocation
-- First, find the title to use
local titleobj = mw.title.new(frame:getParent():getTitle())
local title
if titleobj.namespace == 10 then -- NS_TEMPLATE
title = titleobj.text
elseif titleobj.namespace == 0 then -- NS_MAIN
title = ':' .. titleobj.text
else
title = titleobj.prefixedText
end
-- Build the invocation body with numbered args first, then named
local ret = '{{' .. title
for k, v in ipairs( args ) do
if string.find( v, '=', 1, true ) then
-- likely something like 1=foo=bar, we need to do it as a named arg
break
end
ret = ret .. '|' .. v
args[k] = nil
end
for k, v in pairs( args ) do
ret = ret .. '|' .. k .. '=' .. v
end
return ret .. '}}'
else
---- Not substing
-- Just return the "body"
return frame.args['$B'] .. (frame.args['$N'] and frame:getParent():getTitle() == mw.title.getCurrentTitle().prefixedText and '[[Category:Calls to Module:Unsubst that use $N]]' or '')
end
end
return p