Using varargs without having . . . as an function argument?

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#1

For example,

function myFunction(a,b,c)
  if true then
     otherFunction(...)
  end

  return a * b
end

How would I do this without declaring … as myFunction’s parameter?

#2

Are you sure this is correct syntax? ... cannot be used as an argument, it’s set as a parameter. Can you please what you’re asking about more?

#3

My apologies, I meant parameter. I would like to be able to pass all arguments to another function while still defining parameters a, b, c, etc. I know I can unpack … but I wasn’t sure if there is a simpler way, like shown in my code example.

#4

Oh I see, do you know how many parameter there will be? If so, you can do

function myFunction(a,b,c)
  if true then
     otherFunction(a,b,c)
  end

  return a * b
end

But if you don’t, you would have to use unpack, I doubt there is any other way.

function myFunction(a,b,c)
  if true then
     otherFunction(unpack({a,b,c}))
  end

  return a * b
end

There is another way, using debug.info, which actually returns a function’s parameters, sadly roblox has that disabled

1 Like
#5

I do not know how many parameters there would be. I was hoping there would be something like using debug.info where you can get the parameters of the function. Thanks for your valuable feedback!

#6

You could pack varargs with table.pack and define a, b and c and the first 3 indexes:

local function MyFunction(...)
    local Args = table.pack(...)
    local A, B, C = Args[1], Args[2], Args[3]
    --// Code
end
#7

Also a correction, debug.info doesn’t return the actual values corresponding to the parameter, it returns the actual name of each parameter, so if you had a parameter a, it would return a string "a"

#8

That’s exactly he’s problem I think, he doesn’t want to do

local function MyFunction(...)
--he wants to do
local function MyFunction(a,b,c)
#9
#10

I am aware that this is an XY problem! But obviously the user knew ... existed, he was just wondering if there was another way of doing it.

#11

No need for tables or unpacking!

Following your example…

local function myFunction(...)
    local a, b = ... -- define a, b as the first two arguments

    if (condition) then
        otherFunction(...)
    end

    return a * b
end

Since your function always expects some values for a and b, you can define it like this:

local function myFunction(a, b, ...)
    if (condition) then
        otherFunction(a, b, ...)
    end

    return a * b
end
6 Likes
#12

Huge oversight on my end, makes complete sense to use your second example. Thanks!

1 Like
#13

Sorry, that was not directed at you.

1 Like