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* simple recursive function in plpgsql fails
@ 2002-06-13 23:39 Andrew Hammond <drew@xyzzy.dhs.org>
2002-06-14 05:02 ` Re: simple recursive function in plpgsql fails Tom Lane <tgl@sss.pgh.pa.us>
0 siblings, 1 reply; 2+ messages in thread
From: Andrew Hammond @ 2002-06-13 23:39 UTC (permalink / raw)
To: pgsql-sql
ians=# SELECT version();
version
---------------------------------------------------------------
PostgreSQL 7.1.3 on i686-pc-linux-gnu, compiled by GCC 2.95.4
My goal is to find the last occurance of a pattern in a string. As a
helper function, I wrote this:
DROP FUNCTION reverse(text);
CREATE FUNCTION reverse(text) RETURNS text AS
'DECLARE str ALIAS FOR $1;
BEGIN IF length(str) > 1 THEN
RETURN reverse(substr(str, 2)) || substr(str, 1, 1);
ELSE
RETURN str;
END IF;
END;' LANGUAGE 'plpgsql'
ians=# SELECT reverse('q');
reverse
---------
q
(1 row)
ians=# SELECT reverse('qw');
reverse
---------
wq
(1 row)
ians=# SELECT reverse('qwe');
reverse
---------
ewq
(1 row)
ians=# SELECT reverse('qwer');
reverse
---------
rerq
(1 row)
Ooops...
------------------------------------------------------------------------
Andrew G. Hammond drew@xyzzy.dhs.org <mailto:drew@xyzzy.dhs.org>
http://xyzzy.dhs.org/~drew/ <http://xyzzy.dhs.org/%7Edrew/;
56 2A 54 EF 19 C0 3B 43 72 69 5B E3 69 5B A1 1F 613-389-5481
5CD3 62B0 254B DEB1 86E0 8959 093E F70A B457 84B1
^ permalink raw reply [nested|flat] 2+ messages in thread
* Re: simple recursive function in plpgsql fails
2002-06-13 23:39 simple recursive function in plpgsql fails Andrew Hammond <drew@xyzzy.dhs.org>
@ 2002-06-14 05:02 ` Tom Lane <tgl@sss.pgh.pa.us>
0 siblings, 0 replies; 2+ messages in thread
From: Tom Lane @ 2002-06-14 05:02 UTC (permalink / raw)
To: Andrew Hammond <drew@xyzzy.dhs.org>; +Cc: pgsql-sql
Andrew Hammond <drew@xyzzy.dhs.org> writes:
> [ problems with a recursive plpgsql function ]
Yeah, there are some known bugs there :-(. AFAICS this cannot be
fixed properly until we get around to doing the querytree restructuring
that I keep ranting about --- in particular, making a clean distinction
between plan tree and execution state.
regards, tom lane
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2002-06-13 23:39 simple recursive function in plpgsql fails Andrew Hammond <drew@xyzzy.dhs.org>
2002-06-14 05:02 ` Tom Lane <tgl@sss.pgh.pa.us>
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