Module:Pcall

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Pcall

Description	This module attempts to suppress the display of any error
Status	Alpha
Updated	May 28, 2026 (2 months ago)

This module attempts to suppress the display of any error

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--- This module attempts to suppress the display of any error
-- @module pcall
-- @alias p
-- @release alpha

local p = {}

--- Does the call.
local function doCall(modToCall, frame, template, pckg, fail, includeError)
	if template then
		local templateTitle = mw.title.new(modToCall, 10)

		local success, result = pcall(function() 
			return frame:expandTemplate(templateTitle.fullText, frame.args)
		end)
		if success then
			return result
		else
			if includeError then
				return result
			else
				return fail
			end
		end
	else
		if pckg == nil then error(mw.message.new("scribunto-common-nofunction"):plain()) end
		local callMod = require("Module:" .. modToCall) or error(mw.message.new("scribunto-common-nosuchmodule", 0, modToCall):plain())
		local toCall = callMod[pckg] or error(mw.message.new("scribunto-common-nosuchfunction", 0, pckg):plain())
		if type(toCall) ~= type(function() end) then error(mw.message.new("scribunto-common-notafunction", nil, pckg):plain()) end
		local success, result = pcall(toCall, frame)
		if success then
			return result
		else
			if includeError then
				return result
			else
				return fail
			end
		end
	end
end


--- Main function.
-- @param {table} frame Calling frame.
-- @return Wikitext output.
local function main(modToCall, frame, template)
	local pckg = frame.args[1]
	local fail = frame.args["_fail"] or ''
	local includeError = frame.args["_error"]
	local newFrame = {}
	for k,v in pairs(frame) do
		newFrame[k] = newFrame[k] or {}
		if type(v) == 'table' then
			for l,w in pairs(v) do
				newFrame[k][l] = w
			end
		end
	end
	local topArg = 2
	for k,v in ipairs(newFrame.args) do
		if k - 1 >= 1 then
			newFrame.args[k - 1] = v
		end
		if k > topArg then
			topArg = k
		end
	end
	newFrame.args[topArg] = nil
	
	-- get rid of first underscore for arguments "__fail" and "__includeerror"
	for k,v in pairs(newFrame.args) do
		if type(k) ~= type(1) then
			if k:find("__fail") or k:find("__error") then
				newFrame.args[k:sub(-k:len() + 1)] = v
				newFrame.args[k] = nil
			end
		end
	end
	
	return doCall(modToCall, newFrame, template, pckg, fail, includeError)
end

setmetatable(p, {
	__index = function(_, index)
		local title = mw.title.new(index, 828)
		if title.namespace ~= 828 then
			return function(frame)
				return main(index, frame, true)
			end
		end
		return function(frame)
			for k,v in pairs(frame.args) do
				mw.log(k .. '=' .. v)
			end
			return main(index, frame, false)
		end
	end
})

return p