Module:Template wrapper

Documentation for this module may be created at Module:Template wrapper/doc

require('Module:No globals');

local p={};
local error_msg = '<span style=\"font-size:100%\" class=\"error\"><code style=\"color:inherit; border:inherit; padding:inherit;\">&#124;_template=</code> missing or empty</span>';


--[[--------------------------< I S _ I N _ T A B L E >--------------------------------------------------------

scan through tbl looking for value; return true if found, false else

]]

local function is_in_table (tbl, value)
    for k, v in pairs (tbl) do
        if v == value then return true end
    end
    return false;
end


--[[--------------------------< A D D _ P A R A M E T E R >----------------------------------------------------

adds parameter name and its value to args table according to the state of boolean list argument; kv pair for
template execution; k=v string for template listing.

]]

local function add_parameter (k, v, args, list)
	if list then
		table.insert( args, table.concat ({k, '=', v}));						-- write parent frame parameter names and values to args table as string
	else
		args[k] = v;															-- copy parent frame parameters to args table
	end
end


--[[--------------------------< F R A M E _ A R G S _ G E T >--------------------------------------------------

Fetch the template's 'default' and control parameters; adds default parameters to args

returns content of |_template= parameter; nil else

]]

local function frame_args_get (frame_args, args, list)
	local template;

	for k, v in pairs (frame_args) do											-- here we get the wrapper template's 'default' parameters
		if '_template' == k then
			template = v;														-- save the name of template that we are wrapping
		elseif '_exclude' ~= k then												-- _exclude already handled so ignore it here
			add_parameter (k, v, args, list);									-- add all other parameters to args in the style dictated by list
		end
	end

	return template;															-- return contents of |_template= parameter
end


--[[--------------------------< P F R A M E _ A R G S _ G E T >------------------------------------------------

Fetch the template's 'live' parameters; adds live parameters that aren't members of the exclude table to args table

no return value

]]

local function pframe_args_get (pframe_args, args, exclude, list)
	for k, v in pairs (pframe_args) do
		if 'string' == type (k) and not is_in_table (exclude, k) then			-- do not pass along positional or excluded parameters
			if v and ('' ~= v) then												-- pass along only those parameters that have assigned values
				if 'unset' == v:lower() then									-- special keyword to unset 'default' parameters set in the wrapper template
					v = '';														-- unset the value in the args table
				end
				add_parameter (k, v, args, list)								-- add all other parameters to args in the style dictated by list
			end
		end
	end
end


--[[--------------------------< _ M A I N >--------------------------------------------------------------------

Collect the various default and live parameters into args styled according to boolean list.

returns name of the wrapped or listed template or nil for an error message

]]

local function _main (frame, args, list)
	local template;
	local exclude = {};															-- table of parameter names for parameters that are not passed to the wrapped template
	
	if frame.args._exclude and ('' ~= frame.args._exclude) then					-- if there is |_exclude= and it's not empty
		exclude = mw.text.split (frame.args._exclude, "%s*,%s*");				-- make a table from its contents
	end

	template = frame_args_get (frame.args, args, list);							-- get parameters provided in the {{#invoke:template wrapper|...|...}}
	if nil == template or '' == template then									-- this is the one parameter required by this module
		return nil;																-- not present, tell calling funtion to emit an error message
	end
	
	local pframe = frame:getParent();											-- here we get the wrapped template's 'live' parameters from pframe.args
	pframe_args_get (pframe.args, args, exclude, list);							-- add parameters and values to args that are not listed in the exclude table

	return template;															-- args now has all default and live parameters, return wrapped template name
end


--[[--------------------------< W R A P >----------------------------------------------------------------------

Template entry point.  Call this function to 'execute' the wrapped template

]]

function p.wrap (frame)
	local args = {};															-- table of default and live parameters and their values to be passed to the wrapped template
	local template;																-- the name of the wrapped template

	template = _main (frame, args, false);										-- get default and live parameters and the name of the wrapped template
	if not template then														-- template name is required
		return error_msg;														-- emit error message and abandon if template name not present
	end
	
	return frame:expandTemplate {title=template, args=args};					-- render the template
end


--[[--------------------------< L I S T >----------------------------------------------------------------------

Template entry point.  Call this function to 'display' the source for the wrapped template.  This function added
as a result of a TfD here: Wikipedia:Templates_for_discussion/Log/2018_April_28#Module:PassArguments

This function replaces a similarly named function which was used in {{cite compare}}

Values in the args table are numerically indexed strings in the form 'name=value'
Template:Cite newspaper The Times/testcases
]]


function p.list (frame)
	local args = {};															-- table of default and live parameters and their values to be passed to the listed template
	local template;																-- the name of the listed template

	template = _main (frame, args, true);										-- get default and live parameters and the name of the listed template
	if not template then														-- template name is required
		return error_msg;														-- emit error message and abandon if template name not present
	end

	return frame:preprocess (table.concat ({'<code style="color:inherit; background:inherit; border:none;"><nowiki>{{', template, ' |', table.concat( args, ' |' ), '}}</nowiki></code>'}));	-- render the template
end

return p;