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Re: A proposal for reserved read-syntax characters

This page is part of the web mail archives of SRFI 75 from before July 7th, 2015. The new archives for SRFI 75 contain all messages, not just those from before July 7th, 2015.

bear <bear@xxxxxxxxx> writes:

> 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.

Yes. SRFI-75 currently talks about "whitespace", and I think this
has to be extended.

> Just looking at the categories, I think characters with
> the "General Category" of CC (control characters) CF
> (formatting controls), PS (open punctuation), PC (close
> punctuation) ZL (line separator), ZP (paragraph separator)
> and ZS (space separator) should probably be excluded from
> identifiers.

I agree with that (from a quick skim through the Unicode list that
looks good). I'm a bit reluctant about Ps and Pc, but for example
< and > is not in that list, so that might be ok.

> 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.

Dingbats can make nice identifiers! ;-)

No really, I don't think we should reserve characters for such a
use. If we exclude Ps and Pc, there are a lot of possible
characters for use there already. No need to create more.

        -- Jorgen

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