Arguments that I pass to a lua script are nil

Question

I am writing a Lua 5.3 program and it requires arguments to be passed to it. I use the arg table to get the first argument: arg[1], but the 1st argument, according to the script, is nil even though I have passed an argument to the file.

Here's the code that I've written:

local strin = arg[1]:sub(2,arg[1]:len()-1)   -- to remove the quote marks
local i = 0
for W in strin:gmatch(".") do
    i = i + 1
    if W == " " or W == "\t" then strin = strin:sub(i+1) else break end
end
print(strin)

I pass the argument to the file like this:

C:\Users\WhiteKid\Documents\Scripts>RemoveWhiteSpace.lua "     hello world!"

It thinks arg[1] is a nil value when it is not. Is there a different way of getting the arguments passed to a lua script in Lua 5.3?

What happens with the minimal script for k, v in pairs( arg ) do print( k, v ) end? — nobody
– nobody, Commented Jun 30, 2017 at 23:44
When passing arguments to it? Because that would mean something else is broken. — nobody
– nobody, Commented Jul 1, 2017 at 2:50
Yes. I feel like it might be something with my version of lua. I have Lua 5.3 — AAAAAAAAA EEEEEEEEEEEEEEEEEEEE
– AAAAAAAAA EEEEEEEEEEEEEEEEEEEE, Commented Jul 1, 2017 at 3:55

Paul Kulchenko · Accepted Answer · 2017-07-01 06:04:41Z

2

Since you are calling the .lua script directly (C:\Users\WhiteKid\Documents\Scripts>RemoveWhiteSpace.lua " hello world!"), you seem to have an association with a lua interpreter. You need to make sure you pass %1 or %* to the interpreter you are calling in that association. Alternatively, try calling the Lua interpreter and passing the script name and the parameters and it should work as you expect.

Also, you should check if arg[1] is present and check if the quotes are also there (as they may be removed before the parameters get to the script, so you should not always expect them).

answered Jul 1, 2017 at 6:04

Paul Kulchenko

26.9k3 gold badges43 silver badges64 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Arguments that I pass to a lua script are nil

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related