Lua How to convert a string into a variable name?

[Xikini]

I've been wracking my brain trying to figure this out.. xD

So in the source we basically have this..

CONST_ME_NONE = 0
CONST_ME_DRAWBLOOD = 1
CONST_ME_LOSEENERGY = 2

in the script I have this..

local effects = {CONST_ME_NONE, CONST_ME_DRAWBLOOD, CONST_ME_LOSEENERGY}

local user_input = "CONST_ME_NONE"

for i = 1, #effects do
    if effects[i] == user_input then
        -- do something
    end
end

How do I convert user_input into the variable name, so that I can then use it to compare against what's in the table without needing to explicitly write out a look-up table?

 

[oen432]

load("return " .. user_input)()

local user_input = "CONST_ME_DRAWBLOOD"
position:sendMagicEffect(load("return " .. user_input)())

#Edit
loadstring is obsolete in 5.1+ Lua version, changing to load.

#Edit2
This is not secure, if this is used in TalkAction, then player can simply execute Lua code with this script.

 

[Xikini]

This is not secure, if this is used in TalkAction, then player can simply execute Lua code with this script.

Oh hmm.
Yeah I was planning on using this in a talkaction, and possibly npc scenario's.
Using the loadstring is useful, since I can use numbers or the variable name and get the same result.

Can you think of any alternative other then writing out the look-up table for this specific use-case?

local effects = {
    ["CONST_ME_NONE"] = CONST_ME_NONE,
    ["CONST_ME_DRAWBLOOD"] = CONST_ME_DRAWBLOOD,
    ["CONST_ME_LOSEENERGY"] = CONST_ME_LOSEENERGY
}

 

[oen432]

Try _G[user_input]

 

[Xikini]

Try _G[user_input]

I swear I tried this earlier and couldn't get it to work. lmao

Thank you.

Post automatically merged: Aug 22, 2020

Try _G[user_input]

Sorry to ping you, but it's basically the same thing in reverse.. xD
How do I print the variable name instead of the value?
lmao it seems so simple, but googling for 2 hours has literally got me no-where.

local effects = {CONST_ME_NONE, CONST_ME_DRAWBLOOD, CONST_ME_LOSEENERGY}

print(effects[1]) -- this prints '0'.. how do I make it print "CONST_ME_NONE"

 

[oen432]

Not possible in pure Lua.