Re: Issue: READ-CASE-SENSITIVITY (Version 1)

[Jeff Dalton <jeff%aiai.edinburgh.ac.uk@NSS.Cs.Ucl.AC.UK>]

> The intent that READ be useful as a lexer for data or embedded
> languages is clear.  It's also clear that you're asking for an
> extension to the lexer's power that is not required for Common Lisp.

Sure, but character macros aren't required for reading standard-syntax
Common Lisp either.

> I think that it is a reasonable and useful extension if properly
> defined.  

Thanks.

> You can put me down as likely to support a readtable-based case
> control extension, however Peck's point that such an extension must
> not conflict with the new character proposal is important.

Hummm.  I don't think it should be hard to be compatible.  Automatic
case conversion seems more likely to run into trouble when there are
lots of different character sets (some, presumably, without a notion
of case).

But it's nontrivial to design something of this sort.  The options seem
to be:

  * some way just to turn case concersion on and off
  * a way to specify a conversion for every character
    (normally, some would be converted to upper case)
    [I can imagine lots of objections to this since
    it would make readtables bigger, it would have to
    say what happens when one of the characters is
    defined as a macro, etc.]
  * define some way for character macro functions to return
    a substitute character (or characters?).
  * [maybe] specify an alternative character set that doesn't
    have case conversion.

Any preferences?

-- Jeff