Re: PATCH: Support for Pascal strings

[Mark Mitchell <mark at codesourcery dot com>]

--On Monday, June 18, 2001 02:31:49 PM -0700 Stan Shebs <shebs@apple.com> 
wrote:

> ruling that \p with the semantics as proposed by Zem is permanently
> unacceptable for FSF GCC, and then we can move on to the many other
> things that need to be done.

Even though I am normally the most rabid anti-extensionist on this list, I 
am
sympathetic to this particular extension.  I do think that it needs to have
complete semantic documentation, which means answering the questions Joseph
raised about what happens with `const char s[2] = "\pxy"' and such.

The reason I am disposed favorably towards this extension is that it is, I 
think,
relatively easy to figure out what all of those questions are -- and then 
to come
up with reasonable answers.  Once the string enters the compiler proper, it 
is
almopst like any other string -- "\pxy" is just like "\002xy", but without 
a
terminating NUL.

I do think that we need to get a complete description of the semantics. 
Basically,
I think the questions boil down to:

  - What is the type of "\p..."?

  - What is the representation of "\p..."?

I think the answers are:

  - `char[n]' where `n' is one greater than the number of characters in the
    string itself , in order to allow room for the `\p'.  And make the 
elements
    of the array `const char' in those modes where we do the same for an 
ordinary
    string literal.

  - The string, without a trailing NUL, prefaced with a length byte.

Given that, I should think that the entire change could be done in 
lex_string.

--
Mark Mitchelll               mark@codesourcery.com
CodeSourcery, LLC            http://www.codesourcery.com