Re: :PgSQL: More Queestions

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.