[Doc-SIG] reserved characters

[Edward D. Loper]

> Well, ST's *do* have reserved characters, sort of, but the problem is
> that they're not reserved in all circumstances. So, in STpy, '#' is
> special, but only in the context of after a space or beginning of line
> and before a non-space that isn't '#', and so on (i.e., when it is
> acting as a quotation character).

The idea would be that specific ST's would be allowed to use
reserved characters if they want, or remove them from the reserved
character list if they want.  So in STminus, we would have::

   ReservedChars = # | @

And in STpy, we would have::

   ReservedChars = #

This production would take care of making sure that those characters
don't appear in normal text.

> I think that for STminus's purposes, it might make sense to make
> characters reserved, *perhaps*, but for the "full fledged" ST's it
> doesn't (they're much more Perl like in this respect, whether Perl works
> like that or not (I don't know) since they assume that people can cope
> with the meaning of a character changing depending on its
> environment/use).

Certainly.  Each full-fledged ST would probably un-reserve the
characters they don't use.  The main idea here would be to add a
"hook" for us to add in future things like advanced markup, if we
later decide we want to.  The potential problem is:

    1. we make our markup language
    2. everyone loves it, it gets used everywhere
    3. everyone decides that advanced markup is a good idea after all
    4. no one wants to make changes that will mess up all the docs
       that they've already written.

> '[' and ']' are "force a reference" characters in Zwiki, and will be
> used for similar purpose in STpy. But again, it depends on context.

Hm.  I'm not sure I like the sound of that.  Care to elaborate?

> The only thing I *might* give away is '@', since it is rarely used in
> text, and not meaningful in Python (but you discuss that in another
> email)

So if we decide we want reserved characters, we might limit it to this.

-Edward