Does a function in VBscript take variable number of arguments?

Question

For example, if I have a function in VBscript:

Function sum(a, b, c)
    sum = a + b + c
End function

Now, in the main, I make two variables and pass them into the function sum as the following:

Dim a : a = 1
Dim b : b = 2
Call sum(a, b)

Will this work or not, and why? Thanks.

Answer 1

It will not work, VBScript doesn't support optional arguments.
I'd use a function that takes an array of numbers instead vary number of arguments to getting sum.

Function sum(nums)
    Dim i, out
    For i = 0 To UBound(nums)
        out = out + nums(i)
    Next
    sum = out
End function

Call sum(Array(1, 2, 3, 4))

Answer 2

According to this, VBscript does not support optional arguments. You can do what they suggest and pass null values to your function.

Answer 3

I hope this might help. I use dictionary object to pass variables to function so I can add new arguments without the need for refactoring existing code.

dim params
set params = CreateObject("Scripting.Dictionary")

'...when I want to call a function
params.add "variable_name", value: params.add "variable_name_2", value ': ...
call fn_function_name(params)


'...declaring a function
function fn_function_name(byRef params_in)

    'here I usually make sure that variable is of correct type, or that is set
    params_in("variable_name") = fn_check(params_in("variable_name"), "number") ' fn_check is a separate function

    ' ... function code goes here ...

    ' in order to user external dictionary "params" multiple times, I empty dictionary before exiting the function. This is possible because I set it as a reference (byRef) instead of value
    params_in.removeAll()
end function

Answer 4

VBScript doesn't support optional arguments or method overloading. You can pass in null values to your function call, however.