bear scripsit:

> I agree that certain characters ought not appear in
> identifiers without use of some escape mechanism.  But
> rather than list them, I'd prefer to do it by category.

That's what I did, only rather than using simply the General Category
field in UnicodeData, I also used the Pattern_Syntax property in PropList
(at http://www.unicode.org/Public/UNIDATA/PropList.txt )

The list was not definitional, simply an attempt to give people a feel
for the kinds of characters included by the property-based definition.

Essentially, the characters on the list are those that are both
Pattern_Syntax and punctuation.

> If we want to reserve a bunch of characters for reader
> macros in implementations where reader macros are definable,
> I'd suggest the class SO (other symbols, including dingbats);
> they're eyecatching, occasionally iconic, and for the most
> part linguistically neutral.

Not only are they not always neutral (as you noted), but they cover
very many useful symbols that are suitable for naming either functions
or variables.

--
John Cowan  www.ccil.org/~cowan  www.reutershealth.com  xxxxxx@reutershealth.com
There are books that are at once excellent and boring.  Those that at
once leap to the mind are Thoreau's Walden, Emerson's Essays, George
Eliot's Adam Bede, and Landor's Dialogues.  --Somerset Maugham