Module:Lua call

This module allows you to call any one single preinstalled Lua function, so that you don't need to write a module for one desired feature.

Usage

Main

{{#invoke:Lua call|main|Template:Var|Template:Var|Template:Var}}

The Template:Var are any key of your choice = any value of your choice. Values are interpreted as strings unless tonumber(value) isn't nil, i.e. numbers should be converted to the numeric type. No effort is made to interpret tables.

The Template:Var all begin with reserved_, which arbitrary variable should use.

• reserved_return sets which output from the function you want, and defaults to 1. For example, setting it to 2 for mw.ustring.gsub will return the number of replacements made.
• reserved_debug - nonzero value forces display of a not particularly useful debug text

The Template:Var is written as Template:Var(Template:Var) where Template:Var means something in the Extension:Scribunto/Lua reference manual and Template:Var are the arbitrary variable names you've chosen.

Examples

Main

• {{#invoke:Lua call|main|a=test |b=7|string.rep(a,b)}} → test test test test test test test 
• {{#invoke:Lua call|main|pattern=(%a)|replace=%1.|string=I can't get no satisfaction|mw.ustring.gsub(string,pattern,replace)|reserved_return=1}} → I. c.a.n.'t. g.e.t. n.o. s.a.t.i.s.f.a.c.t.i.o.n.
• {{#invoke:Lua call|main|pattern=(%a)|replace=%1.|string=I can't get no satisfaction|mw.ustring.gsub(string,pattern,replace)|reserved_return=2}} → 22
• {{#invoke:Lua call|main|value=1.4512|math.ceil(value)}} → 2
• {{#invoke:Lua call|main|value=1.4512|math.modf(value)}} → 1
• {{#invoke:Lua call|main|value=1.4512|math.modf(value)|reserved_return=2}} → 0.4512
• {{#invoke:Lua call|main|mw.text.nowiki(s)|s={{URL|1=https://www.Amazon.com/}}}} → <span class="url">[https://www.Amazon.com/ www<wbr/>.amazon<wbr/>.com]</span>

Call

• {{#invoke:Lua call|call|string.format|%04x|127}} → 007f
• {{#invoke:Lua call|call|math.modf|1.4512}} → 1
• {{#invoke:Lua call|call|math.modf|1.4512|return=2}} → 1
• {{#invoke:lua call|call|mw.text.unstripNoWiki|<nowiki>[[Wikipedia]]</nowiki>}} → Wikipedia

Errors

The module may generate script errors — whenever your call is not valid Lua code, you see the error you would normally have. For example,

{{#invoke:Lua call|main|value=1.4512|math.fmod(value)}} →

because the second value is lacking. No effort is made to trap these.

---

require[[strict]]
local p={}

function p.main(frame)
    local parent = frame.getParent(frame) or {}
    local explist = {}
    local fnname, varlist
    local vars = {}
    for k, v in pairs(_G) do
        vars[k] = v -- transfer every global directly to our variable table
    end
    for k, v in pairs(parent.args or {}) do
        vars[k] = tonumber(v) or v -- transfer every parameter directly to our variable table
    end
    for k, v in pairs(frame.args or {}) do
        vars[k] = tonumber(v) or v -- transfer every parameter directly to our variable table
    end
     --- Alas Scribunto does NOT implement coroutines, according to
     --- https://www.mediawiki.org/wiki/Extension:Scribunto/Lua_reference_manual#string.format
     --- this will not stop us from trying to implement one single lousy function call
    if vars[1] then
        fnname, varlist = mw.ustring.match(vars[1], "^%s*(%a[^%s%(]*)%(([^%)]*)%)%s*$")
    end
    if varlist then
        local expn = 0
        repeat
            expn = expn + 1
            explist[expn] = vars[mw.ustring.match(varlist, "([^%,]+)")]
            varlist = mw.ustring.match(varlist, "[^%,]+,(.*)$")
        until not varlist
    end
    local scopetab = vars
    while mw.ustring.match(fnname, "%.") do
        local scopekey
        scopekey, fnname = mw.ustring.match(fnname, "^(%a[^%.]*)%.(.*)$")
        scopetab = scopetab[scopekey]
    end
    local fn = scopetab[fnname]
    if type(fn) ~= "function" then --XXX: What about callable tables?
        return tostring(fn)
    else 
    	local output = {fn(unpack(explist))}
        return output[vars.reserved_return or 1]
    end
end

local function tonumberOrString(v)
	return tonumber(v) or v:gsub("^\\", "", 1)
end

local function callWithTonumberOrStringOnPairs(f, ...)
	local args = {}
	for _, v in ... do
		table.insert(args, tonumberOrString(v))
	end
	return (f(unpack(args)))
end

--[[
------------------------------------------------------------------------------------
-- ipairsAtOffset

-- This is an iterator for arrays. It can be used like ipairs, but with
-- specified i as first index to iterate. i is an offset from 1
--
------------------------------------------------------------------------------------
--]]
local function ipairsAtOffset(t, i)
	local f, s, i0 = ipairs(t)
	return f, s, i0+i
end

local function get(s)
	local G = _G; for _ in mw.text.gsplit(
		mw.text.trim(s, '%s'), '%s*%.%s*'
	) do
		G = G[_]
	end
	return G
end

--[[
------------------------------------------------------------------------------------
-- call
--
-- This function is usually useful for debugging template parameters.
-- Prefix parameter with backslash (\) to force interpreting parameter as string.
-- The leading backslash will be removed before passed to Lua function.
--
-- Example:
--    {{#invoke:Lua call|call|mw.log|a|1|2|3}} will return results of mw.log('a', 1, 2, 3)
--    {{#invoke:Lua call|call|mw.logObject|\a|321|\321| \321 }} will return results of mw.logObject('a', 321, '321', ' \\321 ')
--
-- This example show the debugging to see which Unicode characters are allowed in template parameters,
--    {{#invoke:Lua call|call|mw.ustring.codepoint|{{#invoke:Lua call|call|mw.ustring.char|0x0061}}}} return 97
--    {{#invoke:Lua call|call|mw.ustring.codepoint|{{#invoke:Lua call|call|mw.ustring.char|0x0000}}}} return 65533
--    {{#invoke:Lua call|call|mw.ustring.codepoint|{{#invoke:Lua call|call|mw.ustring.char|0x0001}}}} return 65533
--    {{#invoke:Lua call|call|string.format|0x%04x|{{#invoke:Lua call|call|mw.ustring.codepoint|{{#invoke:Lua call|call|mw.ustring.char|0x0002}}}}}} return 0xfffd
--    {{#invoke:Lua call|call|string.format|0x%04x|{{#invoke:Lua call|call|mw.ustring.codepoint|{{#invoke:Lua call|call|mw.ustring.char|0x007e}}}}}} return 0x007e
--    {{#invoke:Lua call|call|string.format|0x%04x|{{#invoke:Lua call|call|mw.ustring.codepoint|{{#invoke:Lua call|call|mw.ustring.char|0x007f}}}}}} return 0x007f
--    {{#invoke:Lua call|call|string.format|0x%04x|{{#invoke:Lua call|call|mw.ustring.codepoint|{{#invoke:Lua call|call|mw.ustring.char|0x0080}}}}}} return 0x0080
--    {{#invoke:Lua call|call|string.format|0x%04x|{{#invoke:Lua call|call|mw.ustring.codepoint|{{#invoke:Lua call|call|mw.ustring.char|0x00a0}}}}}} return 0x00a0
--
------------------------------------------------------------------------------------
--]]
function p.call(frame)
	return callWithTonumberOrStringOnPairs(get(frame.args[1]),
		ipairsAtOffset(frame.args, 1)
	)
end

--local TableTools = require('Module:TableTools')
--[[
------------------------------------------------------------------------------------
-- get
--
-- Example:
--    {{#invoke:Lua call|get| math.pi }} will return value of math.pi
--    {{#invoke:Lua call|get|math|pi}} will return value of math.pi
--    {{#invoke:Lua call|get| math |pi}} will return value of _G[' math '].pi
--    {{#invoke:Lua call|get|_G| math.pi }} will return value of _G[' math.pi ']
--    {{#invoke:Lua call|get|obj.a.5.c}} will return value of obj.a['5'].c
--    {{#invoke:Lua call|get|obj|a|5|c}} will return value of obj.a[5].c
--
------------------------------------------------------------------------------------
--]]
function p.get(frame)
	-- #frame.args always return 0, regardless of number of unnamed
	-- template parameters, so check manually instead
	if frame.args[2] == nil then
		-- not do tonumber() for this args style,
		-- always treat it as string,
		-- so 'obj.1' will mean obj['1'] rather obj[1]
		return get(frame.args[1])
	else
		local G = _G
		for _, v in ipairs(frame.args) do
			G = G[tonumberOrString(v)]
		end
		return G
	end
end

--[[
------------------------------------------------------------------------------------
-- invoke
--
-- This function is used by Template:Invoke
--
------------------------------------------------------------------------------------
--]]
function p.invoke(frame)
	local pframe, usedpargs = frame:getParent(), {}
	-- get module and function names from parent args if not provided
	local pfargs = setmetatable({frame.args[1], frame.args[2]}, {__index = table})
	if not pfargs[1] then
		pfargs[1], usedpargs[1] = pframe.args[1], true
		if not pfargs[2] then
			pfargs[2], usedpargs[2] = pframe.args[2], true
		end
	elseif not pfargs[2] then
		pfargs[2], usedpargs[1] = pframe.args[1], true
	end
	-- repack sequential args
	for i, v in ipairs(pframe.args) do
		if not usedpargs[i] then
			pfargs:insert(v)
			usedpargs[i] = true
		end
	end
	-- copy other args
	for k, v in pairs(pframe.args) do
		if not pfargs[k] and not usedpargs[k] then
			pfargs[k], usedpargs[k] = v, true
		end
	end
	-- #invoke off parent frame so the new frame has the same parent
	return pframe:callParserFunction{name = '#invoke', args = pfargs}
end

return p