Calling a function from a string variable

whoward69 · Apr 9, 2016

Just thought I'd throw this out there (partly so when I next search for the answer, Google will find it!)

Given a function abc

Code:

function abc(iData1, iData2)
    return string.format("Data1=%i, Data2=%i", iData1, iData2);
end

and some data values

Code:

local i1 = 40
local i2 = 60

we can call it

Code:

print(abc(i1, i2))

and get the expected output

Code:

Data1=40, Data2=60

But we can also put the name of the function into a variable

Code:

local xyz = "abc"

execute the function based on the contents of the variable

Code:

print(loadstring("return " .. xyz .. "(...)")(i1, i2))

and also get the expected output

Code:

Data1=40, Data2=60

Enjoy!

whoward69 · May 1, 2016

The loadstring() needs to be wrapped in a pcall(), otherwise errors in the called function (whatever's in xyz) will be silently ignored.

Code:

local status, ret = pcall(function () return loadstring("return " .. xyz .. "(...)")(i1, i2) end)
if (status) then
    print(ret)
end