RE: Anybody experienced with regular expressions and UDFs?

Hi, Gary,

The regular expression is passed by the function to the service program
named in the function. The string (or character) value being tested is also
passed to the service program.

I will try the \b as a prefix to my expression to see if it passes.

Thanks

Tom


-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx
[mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Monnier, Gary
Sent: Wednesday, March 28, 2012 5:55 PM
To: Midrange Systems Technical Discussion
Subject: RE: Anybody experienced with regular expressions and UDFs?

Tom,

I suggest pulling your REGEXEC stuff into a test program. You don't mention
any error code being returned so I'd include regerror() in my test program.
It can be a life saver.

The test program will allow you to play with the pattern until you find what
you want.

You can also look at
http://www.codeproject.com/Articles/9099/The-30-Minute-Regex-Tutorial they
have a phone number matching pattern of \b\d{3}-\d{4}.

Theirs \b\d{3}-\d{4}
Yours \d{3}-\d{4}

Maybe all you are missing is the \b?

HTH,

Gary Monnier

-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx
[mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Thomas Garvey
Sent: Wednesday, March 28, 2012 3:31 PM
To: 'Midrange Systems Technical Discussion'
Subject: Anybody experienced with regular expressions and UDFs?

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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