From: "Jeff Urlwin" <jurlwin@bellatlantic.net>
To: "Tim Bunce" <Tim.Bunce@pobox.com>,
	"David Wheeler" <david@wheeler.net>
Cc: "Jeff Urlwin" <jurlwin@bellatlantic.net>, <dbi-dev@perl.org>,
	<pgsql-interfaces@postgresql.org>
Subject: Re: :PgSQL: More Queestions
Date: Thu, 21 Nov 2002 18:05:42 -0500
Message-ID: <OEEMJFLOJPABMFADAPIKGEEEEDAA.jurlwin@bellatlantic.net>
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>
> On Wed, Nov 20, 2002 at 10:30:00PM -0800, David Wheeler wrote:
> > On Wednesday, November 20, 2002, at 06:53  AM, Tim Bunce wrote:
> >
> > >>But if I change it (as I'm seriously considering, in light of
> > >>PostgreSQL 7.3's support for prepared statements), I'll probably do no
> > >>parsing for comments.
> > >
> > >I think that would be a bad move.
> >
> > Yes, your last post makes very clear why. Thanks.
> >
> > >If it's seen the start of a string ("..." or '...') then it just
> > >keeps copying the string till it finds the same type of quote
> > >character to mark the end of the string. The 'fiddly bit in the
> > >middle' is handling backslashes used to escape quote chars in the
> > >middle of the string:  "...\"..." and "...\\" (odd vs even number).
> >
> > Seems rather opaque. Maybe I'm just reflecting my C-newbieness, but why
> > wouldn't this work as well? Borrowing a bit from DBD::ODBC here (but
> > allowing for both kinds of escaping of the quote characters):
> >
> >         if (*src == '"' || *src == '\'') {
> >             if (!in_literal) {
> >                 literal_ch = *src;
> >                 in_literal = 1;
>
> No need for in_literal as literal_ch can serve as a flag as well.

True...I was hacking that in and overlooked it.

>
> >             } else {
> >                 if (*src == literal_ch && *(src-1) != '//'
> >                     && *(src-1) != literal_ch) {
> >                     in_literal = 0;
> >                 }
> >             }
> >         }
>
> Can't distinguish between
> 	"....\\\\"	- final double quote ends the string
> 	"...\\\\\"	- final double quote is escaped and string
> continues...
>
> If the original code isn't broken it doesn't need fixing, maybe
> just commenting.

I'm tempted to leave it, since nobody is complaining, at the moment...but
I'll put it on the list.


Jeff