Re: RFE: Regular expression scan AND replace

Perl and Java both use NFA Engine Type ( Nondeterministic Finite Automaton
/cough ) so they are indeed a very similar flavour as far as what
functionality is available, although of course they are implemented through
the language quite differently - In Perl, regular expressions are a
first-class low-level feature of the language whereas in Java you would use
regular expressions via objects and methods...

The support built into DB2 for regular expression is also NFA and so I'm
finding pretty consistent behaviour between Java, DB2 and Perl for general
regex use.

If you haven't seen the DB2 support, you can use the predicate regexp_like
and functions such as regexp_count, regexp_instr, regexp_replace and
regexp_substr.

I threw up a simple test screen that I use to check how DB2 will work with
my regular expressions - here is how you can code a couple of them in RPGLE:

Exec SQL
Set :Scn_Match :ExtrInd
= regexp_replace( :DataStr,
:RegExp,
:ReplaceExp,
:Scn_FromPos, //‚Scan from Pos 1
:Scn_RepOccur, //‚Occurrance to replace 0 = all
:Flags //‚Use enhanced EOL match
);


Exec SQL
Set :Scn_Match :ExtrInd
= regexp_substr( :DataStr,
:RegExp,
:Scn_FromPos,
:Scn_MchOccur,
:Flags ,
:Scn_MchGroup
);

I'll stop now - I'm even boring myself!

On 15 April 2016 at 12:17, Buck Calabro <kc2hiz@xxxxxxxxx> wrote:

On 15 April 2016 at 06:58, Craig Richards <craig@xxxxxxxxxxxxxxxx> wrote:

Having read through Jeffrey Friedl's most excellent book "Mastering

Regular

Expressions" I guess I was thinking from some of the Perl examples, as

Perl

has regular expressions a bit more built into the language.

A very nice recommendation, thanks for this.

The regex provider in RDi is (mostly) the Java regex. If Lpex exposed
a hook for the regex provider I would switch to the Perl regex in an
instant! This isn't a slam on the choice made by the RDi team -
Eclipse is made by and for Java programmers. It's (dare I say it?)
rational (hee hee) that RDi uses the Java regex. But I personally
prefer the Perl regex... Preferences, preferences, preferences. :-)
--buck
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