Bug with sets of complements of classes

["Patrick Donnelly" <batrick.donnelly@...>]

Best way to show this is by example:

Lua 5.1.2  Copyright (C) 1994-2007 Lua.org, PUC-Rio
> return string.match("Hi\t 4", "[%A%S%D]")-- should be nil??
H
> return string.match("Hi\t 4", "[%S%D]") -- correct
H
> return string.match("Hi\t 4", "[%A]")-- produces tab character

> return string.match("Hi\t 4", "[%A%S]")-- wrong again : (
H

It seems Lua isn't correctly forming the union of the complements of classes : (

I couldn't find anything in the manual to say this behavior is
supposed to be undefined.

And yes I realize that:

> return string.match("Hi\t 4", "[^%a%s%d]")
nil

produces the desired behavior :P

-- 
-Patrick Donnelly

"One of the lessons of history is that nothing is often a good thing
to do and always a clever thing to say."

-Will Durant