Module:If empty: Difference between revisions

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(lua doesn't cast nil into blank strings apparently)
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local p = {}
-- this is intended to replace {{If empty}}
 
  +
local p = {};
 
function p.run(frame)
+
function p.main(frame)
local args = require('Module:Arguments').getArgs(frame)
+
local args = require('Module:Arguments').getArgs(frame, {wrappers = 'Template:If empty', removeBlanks = false})
  +
local i = 0
 
  +
-- For backwards compatibility reasons, the first 8 parameters can be unset instead of being blank,
args[table.getn(args)] = ''
 
  +
-- even though there's really no legitimate use case for this. At some point, this will be removed.
while args[i] == nil or string.len(args[i]) == 0 do
 
  +
local lowestNil = math.huge
i = i + 1
 
  +
for i = 8,1,-1 do
  +
if args[i] == nil then
  +
args[i] = ''
  +
lowestNil = i
  +
end
  +
end
  +
  +
for k,v in ipairs(args) do
  +
if v ~= '' then
  +
if lowestNil < k then
  +
-- If any uses of this template depend on the behavior above, add them to a tracking category.
  +
-- This is a rather fragile, convoluted, hacky way to do it, but it ensures that this module's output won't be modified
  +
-- by it.
  +
frame:extensionTag('ref', '[[Category:Instances of Template:If_empty missing arguments]]', {group = 'TrackingCategory'})
  +
frame:extensionTag('references', '', {group = 'TrackingCategory'})
  +
end
 
return v
  +
end
 
end
 
end
return args[i]
 
 
end
 
end
  +
 
return p
 
return p

Latest revision as of 20:41, 23 April 2019

Documentation for this module may be created at Module:If empty/doc

local p = {}

function p.main(frame)
	local args = require('Module:Arguments').getArgs(frame, {wrappers = 'Template:If empty', removeBlanks = false})

	-- For backwards compatibility reasons, the first 8 parameters can be unset instead of being blank,
	-- even though there's really no legitimate use case for this. At some point, this will be removed.
	local lowestNil = math.huge
	for i = 8,1,-1 do
		if args[i] == nil then
			args[i] = ''
			lowestNil = i
		end
	end

	for k,v in ipairs(args) do
		if v ~= '' then
			if lowestNil < k then
				-- If any uses of this template depend on the behavior above, add them to a tracking category.
				-- This is a rather fragile, convoluted, hacky way to do it, but it ensures that this module's output won't be modified
				-- by it.
				frame:extensionTag('ref', '[[Category:Instances of Template:If_empty missing arguments]]', {group = 'TrackingCategory'})
				frame:extensionTag('references', '', {group = 'TrackingCategory'})
			end
			return v
		end
	end
end

return p