Question

I’ve just had an irritating 30 minutes on a "compiler error" in VBA (Access 2003) caused by my use of parenthesis around the arguments I’m passing to a Sub I defined.

I’ve been searching to find a decent article/tutorial/instruction as to when parenthesis are necessary/appropriate/inappropriate/forbidden, but can’t find any clear guidelines.

Answer 1

From Here:

Using the VBScript Call Statement to Call a Subroutine
The use of Call statement is optional when you wish to call a subroutine. The purpose of the Call statement when used with a Sub is to allow you to enclose the argument list in parentheses. However, if a subroutine does not pass any arguments, then you still should not use parentheses when calling a Sub using the Call statement.

Call MySubroutine

If a subroutine has arguments, you must use parentheses when using the Call statement. If there is more than one argument, you must separate the arguments with commas.

Call MySubroutine(intUsageFee, intTimeInHours, "DevGuru") 

Calling the Function
There are two possible ways to call a function. You may either call the function directly, by name only, or you may call it by using the VBScript Call statement.

Calling a Function by Name
When calling a function directly by name and when there is no assignment to a returned value, all of the following are legal syntax:

MyFunction
MyFunction()
MyFunction intUsageFee, intTimeInHours, "DevGuru"

If you want a returned value, you can assign the function to a variable. Note that if there is one or more arguments, you must use the parentheses.

returnval = MyFunction
returnval = MyFunction()
returnval = MyFunction(intUsageFee, intTimeInHours, "DevGuru")