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From: Josh Berkus <josh@agliodbs.com>
Reply-To: josh@agliodbs.com
Organization: Aglio Database Solutions
To: pgsql-sql@postgresql.org, pgsql-hackers@postgresql.org
Subject: Request for builtin function: Double_quote
Date: Mon, 17 Jun 2002 13:34:01 -0700
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Message-Id: <200206171334.01532.josh@agliodbs.com>
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Folks,

Given the amount of qoute nesting we do in Postgres, I thought that we need=
 a=20
function that handles automatic doubling of quotes within strings.   I've=
=20
written one in PL/pgSQL (below).  I'd really love to see this turned into a=
=20
builtin C function.

-Josh

CREATE FUNCTION double_quote(text) returns text as '
DECLARE bad_string ALIAS for $1;
        good_string text;
        current_pos INT;
        old_pos INT;
BEGIN
        IF bad_string IS NULL or bad_string =3D '''' THEN
                RETURN bad_string;
        END IF;
        good_string :=3D bad_string;
        current_pos :=3D  STRPOS(good_string, chr(39));
        WHILE current_pos > 0 LOOP
                old_pos :=3D current_pos;
                good_string :=3D SUBSTR(good_string, 1, (current_pos - 1)) =
||
                        repeat(chr(39), 2) || SUBSTR(good_string, (current_=
pos=20
+ 1));
                current_pos :=3D STRPOS(SUBSTR(good_string, (old_pos + 2)),=
=20
chr(39));
                IF current_pos > 0 THEN
                        current_pos :=3D current_pos + old_pos + 1;
                END IF;
        END LOOP;
RETURN good_string;
END;'
LANGUAGE 'plpgsql'
WITH (ISCACHABLE, ISSTRICT);