OK, I'm no expert at REGEX by a long shot. But, a little digging turned up this info, FWIW:
So regarding compatibility, I can only infer from this that there is a significant level of compatibility based upon the statements listed in the PCRE webpage at
http://www.pcre.org/ :" The PCRE library is a set of functions that implement regular expression pattern matching using the same syntax and semantics as Perl 5" . The current version of PERL according to
http://www.perl.org/ is 5.10.1. So, to paraphrase Kevin, how compatible does compatible need to be?
Then, REGEXTESTER (
http://www.regextester.com/pregsyntax.html) has a blurb that claims to show known compatibility differences. Assuming they can be trusted, they look like the one stop shop for compatibility concerns. The nice thing about this site is that you can test your REGEX here based upon 3 versions: PCRE, EREG and JavaScript.
http://www.regextester.com/
Regards,
Mike
mike.p@xxxxxxxx Cell: (408)679-1011 Office: (815)722-3454
-----Original Message-----
From: web400-bounces@xxxxxxxxxxxx [mailto:web400-bounces@xxxxxxxxxxxx] On Behalf Of Kevin Schroeder
Sent: Thursday, October 29, 2009 1:36 PM
To: Web Enabling the AS400 / iSeries
Subject: Re: [WEB400] iSeries, web development and perl
There are two ways of looking at that. 1. Full compatibility is absolutely, 100% required, or 2. While there are differences, from a practicality standpoint, they are pretty much the same. I use PCRE a decent amount but I'm drawing a blank on a situation where the difference has been unbearable. That's not to say that it's true 100% of the time but it's never bitten me. Based off of the Wikipedia article it seems like recursion in very specific circumstances are the biggest issue. So, it may not be 100% but it works pretty well.
As for dynamic typing increasing maintenance, I'd have some trouble buying that. In PHP there are 8 data types. Integer, Boolean, Float, String, NULL, resource, object and arrays. Objects and arrays can be "strongly" typed in that you can state that you want an array and not a string, or a particular instance of a class. So you have the ability to build a good structure to virtually any sized application.
However, when you deal with the 4 "scalar" types, that is when the dynamic typing occurs. The biggest problem is that (0 == false == null) based off of the type juggling rules and 0, false and null could have different meanings in certain circumstances. But in those cases you can use type sensitivity when you need it by using the === or !== sign. In other words (0 !== false !== null). But once you get into PHP 5 OOP the rules are virtually identical to any strongly typed OO language.
The reason for having these dynamic typing rules is that on the web EVERYTHING is a string. Whether "1" is a string or an integer really doesn't matter that much from a practical standpoint because the browser submitted a string value of 1. There is overhead in having the dynamic typing going on but it makes for very easy to write code.
One place where this COULD be true would be if you have a heavy dependence on associative arrays for structure, like using a struct. However, the simple solution is to use placeholder classes to define the structure you need. There is a minimal amount of overhead in doing that.
Kevin
-----Original Message-----
From: web400-bounces@xxxxxxxxxxxx [mailto:web400-bounces@xxxxxxxxxxxx] On Behalf Of Thorbjoern Ravn Andersen
Sent: Thursday, October 29, 2009 12:42 PM
To: Web Enabling the AS400 / iSeries
Subject: Re: [WEB400] iSeries, web development and perl
Mike Pavlak skrev:
And...keep in mind that PHP on IBM i supports PERL compatible REGEX...So, if that is all you are looking for "It's in There!"
You got me curious, and a bit sceptical since I've worked a lot with
Perl and I know the power of its regular expressions, so I poked around
a bit.
From "
http://en.wikipedia.org/wiki/Perl_Compatible_Regular_Expressions":
"The name is misleading, because PCRE is Perl-compatible only if you
consider a subset of PCRE's settings and a subset of Perl's regular
expression facilities."
Sigh :(
(but I'd like to hear experiences with large PHP programs - my personal
one is that large programs without static typing tends to require more
time when doing maintainance because the compiler simply helps less.
I'd love to be taught otherwise :) )
midrange.com
