Change “~” to “!”

Hello,

As long as I’m whittering on about syntax, I might as well run this up
the proverbial flagpole.

In my experience, “~” is much more commonly associated with
“approximately” than “not”. I understand that it is used for negation in
some mathematical notations, but “in some mathematical notations” covers
a lot of ground. To be honest, I’d expect “￢” rather than “~” in math.
(I suppose “~” may be used in some notations to mean “complement” which
is precisely what we mean in ixml, but even we don’t try to use the
technical term “complement”.)

Furthermore, I think “!” is *very* commonly associated with “not”. It’s
used that way in a whole range of languages with a C-derived syntax.
Steven even has an anecdote about how the use of “!” to mean important
in CSS is confusing *because* so many people think of it as negation.

I propose that we use “!” to negate a character set rather than “~”. In
addition to being (IMHO) more obvious to users, it would free up “~” for
some future use. Given our determination to use US ASCII, we need all
the special characters we can get!

                                        Be seeing you,
                                          norm

--
Norm Tovey-Walsh
Saxonica