RE: Anybody experienced with regular expressions and UDFs?

Thanks, Charles. I would gladly share it but won't waste your time now. An
earlier post informed me that I was expecting ALL regular expressions to be
similar, when I needed to use the POSIX standard.

Thanks again.

Tom Garvey


-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx
[mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Charles Wilt
Sent: Thursday, March 29, 2012 9:00 AM
To: Midrange Systems Technical Discussion
Subject: Re: Anybody experienced with regular expressions and UDFs?

Need to see your CREATE FUNCTION along with the prototype for the RPGLE
code.

Charles

On Wed, Mar 28, 2012 at 6:30 PM, Thomas Garvey <tgarvey@xxxxxxxxxx> wrote:

Hi,

I'm trying to develop a User Defined Function that will test a given
value against a regular expression pattern.  I've found code online by
Scott Klement that utilizes the regcomp (Compile Regular Expression)
and regexec (Execute Compiled Regular Expression) APIs.  I've put this
into an RPGLE module and created a service program, then registered
the UDF using the CREATE FUNCTION command in SQL.  Then I use the
scalar function to test values in a character field of a table.

For example...

SELECT str
FROM   strTable
WHERE regexpsrv(str, '\d{3}-\d{4}') = 1

The function gets passed the test value (str), and the regular
expression pattern (inside the single quotes), and a value of 0 or 1
is returned (1 if the test value contains the regular expression pattern,

0 if not).

The problem is, it ALWAYS returns a zero.  My test database has values
that should sometimes return a zero, but mostly a 1.  Incidentally,
the regular expression essentially is looking for 3 digits, followed
by a dash, followed by 4 digits (a phone number of the form xxx-xxxx).

I can put the thing in debug and the expression is compiled and
returns a zero for the result of the regcomp call.  But the call to
regexec just always returns a zero, as in 'it doesn't match.  The
thing is, I can go to a Regular Expression test site
(http://www.regular-expressions.info/javascriptexample.html), which
allows me to essentially do the same thing (enter a test value and an
expression) to test the expression against various values.  It tells
me the correct results based on the sample data I have.  MY UDF just

rejects everything.

If anyone can point me in a direction, or tell me what I'm doing
wrong, I'd appreciate it very much.

Thanks in advance,

Thomas Garvey

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