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Re: :PgSQL: More Queestions

From: Tim Bunce <Tim(dot)Bunce(at)pobox(dot)com>
To: David Wheeler <david(at)wheeler(dot)net>
Cc: Tim Bunce <Tim(dot)Bunce(at)pobox(dot)com>,Jeff Urlwin <jurlwin(at)bellatlantic(dot)net>, dbi-dev(at)perl(dot)org,pgsql-interfaces(at)postgresql(dot)org
Subject: Re: :PgSQL: More Queestions
Date: 2002-11-21 09:23:16
Message-ID: 20021121092316.GF381@dansat.data-plan.com (view raw or flat)
Thread:
Lists: pgsql-interfaces
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.

>             } 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.

Tim.

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Subject: Re: :PgSQL: More Queestions
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