Subject: Postgres regexp matching failure?
From: Mario Splivalo <mario.splivalo@mobart.hr>
Reply-To: mario.splivalo@mobart.hr
To: pgsql-sql@postgresql.org
Content-Type: text/plain
Organization: Mob-Art
Date: Tue, 05 Sep 2006 12:18:11 +0200
Message-Id: <1157451491.27799.6.camel@localhost.localdomain>
Mime-Version: 1.0
Content-Transfer-Encoding: 7bit

I have an regular expression, wich works fine in Java or python, but I
don't seem to be able to make it work in postgres. Regular expression
needs to match everything begining with '+' (plus sign) or letters
'STOP', 'stop', 'StoP', or any other combination pronounced 'stop'.

Here is the python example:

>>> import re
>>> p = re.compile(r'^\s*(?:[\+|-]|(?:[sS][tT][oO][pP]\b)).*$')
>>> p.match('+mario').group(0)
'+mario'
>>> p.match('+mario works').group(0)
'+mario works'
>>> p.match('mario works').group(0)
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
AttributeError: 'NoneType' object has no attribute 'group'
>>> p.match('stop works').group(0)
'stop works'
>>>

Now, here is what happens if I try this in postgres:

pulitzer2=# select '+mario' ~ '^\s*(?:[\+|-]|(?:[sS][tT][oO][pP]\b)).*
$';
 ?column?
----------
 t
(1 row)

This one is ok.


pulitzer2=# select '+mario works' ~ '^\s*(?:[\
+|-]|(?:[sS][tT][oO][pP]\b)).*$';
 ?column?
----------
 t
(1 row)


This one is also ok.

pulitzer2=# select 'mario works' ~ '^\s*(?:[\
+|-]|(?:[sS][tT][oO][pP]\b)).*$';
 ?column?
----------
 f
(1 row)

Same as this one, also ok.


pulitzer2=# select 'stop works' ~ '^\s*(?:[\
+|-]|(?:[sS][tT][oO][pP]\b)).*$';
 ?column?
----------
 f
(1 row)

Here, postgres should return true, but it gives me false. 

I'd appreciate any hints on what is wrong here.

Thank you in advance,

	Mario
-- 
Mario Splivalo
Mob-Art
mario.splivalo@mobart.hr

"I can do it quick, I can do it cheap, I can do it well. Pick any two."