Module:LuaCall

This module is rated as alpha. It is ready for third-party input, and may be used on a few pages to see if problems arise, but should be watched. Suggestions for new features or changes in their input and output mechanisms are welcome.

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:LuaCall|main|arbitrary variables|parameters|functioncall}}

The arbitrary variables 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 parameters 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 functioncall is written as some.function.name(a,b,c) where some.function.name means something in the Extension:Scribunto/Lua reference manual and a,b,c are the arbitrary variable names you've chosen.

Examples

Main

{{#invoke:LuaCall|main|a=test |b=7|string.rep(a,b)}} → test test test test test test test
{{#invoke:LuaCall|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:LuaCall|main|pattern=(%a)|replace=%1.|string=I can't get no satisfaction|mw.ustring.gsub(string,pattern,replace)|reserved_return=2}} → 22
{{#invoke:LuaCall|main|value=1.4512|math.ceil(value)}} → 2
{{#invoke:LuaCall|main|value=1.4512|math.modf(value)}} → 1
{{#invoke:LuaCall|main|value=1.4512|math.modf(value)|reserved_return=2}} → 0.4512
{{#invoke:LuaCall|main|mw.text.nowiki(s)|s={{URL|1=https://www.Amazon.com/}}}} → [[:Template:URL]]

Call

{{#invoke:LuaCall|call|string.format|%04x|127}} → 007f
{{#invoke:LuaCall|call|math.modf|1.4512}} → 1
{{#invoke:LuaCall|call|math.modf|1.4512|return=2}} → 1

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:LuaCall|main|value=1.4512|math.fmod(value)}} → Lua error at line 35: bad argument #2 to 'reserved_call' (number expected, got no value).

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

local p={}

function p.main(frame)
    local parent=frame.getParent(frame) or {}
    local reserved_value={}
    local reserved_function,reserved_contents
    for k,v in pairs(parent.args or {}) do
        _G[k]=tonumber(v) or v -- transfer every parameter directly to the global variable table
    end
    for k,v in pairs(frame.args or {}) do
        _G[k]=tonumber(v) or v -- transfer every parameter directly to the global variable table
    end
     --- Alas Scribunto does NOT implement coroutines, according to
     --- http://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 _G[1] then
        reserved_function,reserved_contents=mw.ustring.match(_G[1],"^%s*(%a[^%s%(]*)%(([^%)]*)%)%s*$")
    end
    if reserved_contents then
        local reserved_counter=0
        repeat
            reserved_counter=reserved_counter+1
            reserved_value[reserved_counter]=_G[mw.ustring.match(reserved_contents,"([^%,]+)")]
            reserved_contents=mw.ustring.match(reserved_contents,"[^%,]+,(.*)$")
        until not reserved_contents
    end
    local reserved_arraypart=_G
    while mw.ustring.match(reserved_function,"%.") do
        reserved_functionpart,reserved_function=mw.ustring.match(reserved_function,"^(%a[^%.]*)%.(.*)$")
        reserved_arraypart=reserved_arraypart[reserved_functionpart]
    end
    local reserved_call=reserved_arraypart[reserved_function]
    if type(reserved_call)~="function" then
        return tostring(reserved_call)
    else reserved_output={reserved_call(unpack(reserved_value))}
        return reserved_output[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:LuaCall|call|mw.log|a|1|2|3}} will return results of mw.log('a', 1, 2, 3)
--    {{#invoke:LuaCall|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:LuaCall|call|mw.ustring.codepoint|{{#invoke:LuaCall|call|mw.ustring.char|0x0061}}}} return 97
--    {{#invoke:LuaCall|call|mw.ustring.codepoint|{{#invoke:LuaCall|call|mw.ustring.char|0x0000}}}} return 65533
--    {{#invoke:LuaCall|call|mw.ustring.codepoint|{{#invoke:LuaCall|call|mw.ustring.char|0x0001}}}} return 65533
--    {{#invoke:LuaCall|call|string.format|0x%04x|{{#invoke:LuaCall|call|mw.ustring.codepoint|{{#invoke:LuaCall|call|mw.ustring.char|0x0002}}}}}} return 0xfffd
--    {{#invoke:LuaCall|call|string.format|0x%04x|{{#invoke:LuaCall|call|mw.ustring.codepoint|{{#invoke:LuaCall|call|mw.ustring.char|0x007e}}}}}} return 0x007e
--    {{#invoke:LuaCall|call|string.format|0x%04x|{{#invoke:LuaCall|call|mw.ustring.codepoint|{{#invoke:LuaCall|call|mw.ustring.char|0x007f}}}}}} return 0x007f
--    {{#invoke:LuaCall|call|string.format|0x%04x|{{#invoke:LuaCall|call|mw.ustring.codepoint|{{#invoke:LuaCall|call|mw.ustring.char|0x0080}}}}}} return 0x0080
--    {{#invoke:LuaCall|call|string.format|0x%04x|{{#invoke:LuaCall|call|mw.ustring.codepoint|{{#invoke:LuaCall|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:LuaCall|get| math.pi }} will return value of math.pi
--    {{#invoke:LuaCall|get|math|pi}} will return value of math.pi
--    {{#invoke:LuaCall|get| math |pi}} will return value of _G[' math '].pi
--    {{#invoke:LuaCall|get|_G| math.pi }} will return value of _G[' math.pi ']
--    {{#invoke:LuaCall|get|obj.a.5.c}} will return value of obj.a['5'].c
--    {{#invoke:LuaCall|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
	else
		if not pfargs[2] then
			pfargs[2], usedpargs[1] = pframe.args[1], true
		end
	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