Run a string as lua code to call a function with only the function name

Question

I am making a dynamic callback table for a helper function that handles input events. I want to make a(testString) execute when functionTable[1](testString) executes or allow a way for it to be run directly from a string.

functionTable = {}
testString = "atad atad atad"

function a(param)
    print(param)
end

functionTable[1] = "a"

exec(functionTable[1].."(testString)")

How should I be doing this?

(for Lua 5.1)

score 2 · Accepted Answer · answered Sep 07 '20 at 05:17

2

you can use the load() function to execute strings:

functionTable = {}
testString = "atad atad atad"

function a(param)
    print("hello " .. param)
end

functionTable[1] = "a"

load(functionTable[1].."(testString)")()

answered Sep 07 '20 at 05:17

Vinni Marcon

606
1
4
18

1

This works, thank you! Why is the second pair of parentheses necessary? – Grify Dev Sep 08 '20 at 06:29
2

@GrifyDev it is because `load()` is a function that just collects a string and transforms it into a real execution, however it is necessary that we call the function inside load() so that we can actually execute it and collect its return – Vinni Marcon Sep 08 '20 at 06:34
1

I meant the () here – Grify Dev Sep 09 '20 at 03:30
1

load(functionTable[1].."(testString)")__()__ – Grify Dev Sep 09 '20 at 03:30
2

yes exactly, `load()` will only convert the string to an executable, but we still need to call it by the function being called inside `load()` – Vinni Marcon Sep 09 '20 at 03:44

Run a string as lua code to call a function with only the function name

1 Answers1