>I think you're misunderstanding my question. I know that [] can be used as string delimiters and I have a pretty good handle on macro expansion. (At least normally, I do. Right now I'm exhausted and basic syntax is getting me muddled) What I didn't understand is why you gave two ways of doing what I want; one with the delimiters, one without. IOW, what advantage does:
>
>SET FILTER TO custno = [&lccustno]
>
>have over
>
>SET FILTER TO custno = &lccustno
>
>The reason I want to know is because I tried the second one before I asked the question and it didn't work. I'm thinking it's because it interpreted the value of lccustno as being a variable name since there were no quotes, so the first one should work better.
>

That's correct - when you macro-expand, what you get back is parsed into the context of the current line under execution. What's the difference between:

[O'Malley]

and

O'Malley

The original message noted that the second was used where the value being tested was not a string; what's the difference between:

[42]

and

42

Expend some neurochemical energy and look at the problem.