=head1 NAME
-perlfaq1 - General Questions About Perl ($Revision: 1.12 $, $Date: 2003/07/09 15:47:28 $)
+perlfaq1 - General Questions About Perl ($Revision: 3606 $)
=head1 DESCRIPTION
=head2 Which version of Perl should I use?
-You should definitely use version 5. Version 4 is old, limited, and
-no longer maintained; its last patch (4.036) was in 1992, long ago and
-far away. Sure, it's stable, but so is anything that's dead; in fact,
-perl4 had been called a dead, flea-bitten camel carcass. The most
-recent production release is 5.8.1 (although 5.005_03 and 5.6.1 are
-still supported). The most cutting-edge development release is 5.9.
-Further references to the Perl language in this document refer to the
-production release unless otherwise specified. There may be one or
-more official bug fixes by the time you read this, and also perhaps
-some experimental versions on the way to the next release.
-All releases prior to 5.004 were subject to buffer overruns, a grave
-security issue.
-
-=head2 What are perl4 and perl5?
-
-Perl4 and perl5 are informal names for different versions of the Perl
-programming language. It's easier to say "perl5" than it is to say
-"the 5(.004) release of Perl", but some people have interpreted this
-to mean there's a language called "perl5", which isn't the case.
-Perl5 is merely the popular name for the fifth major release (October 1994),
-while perl4 was the fourth major release (March 1991). There was also a
-perl1 (in January 1988), a perl2 (June 1988), and a perl3 (October 1989).
-
-The 5.0 release is, essentially, a ground-up rewrite of the original
-perl source code from releases 1 through 4. It has been modularized,
-object-oriented, tweaked, trimmed, and optimized until it almost doesn't
-look like the old code. However, the interface is mostly the same, and
-compatibility with previous releases is very high.
-See L<perltrap/"Perl4 to Perl5 Traps">.
-
-To avoid the "what language is perl5?" confusion, some people prefer to
-simply use "perl" to refer to the latest version of perl and avoid using
-"perl5" altogether. It's not really that big a deal, though.
+(contributed by brian d foy)
+
+There is often a matter of opinion and taste, and there isn't any one
+answer that fits anyone. In general, you want to use either the current
+stable release, or the stable release immediately prior to that one.
+Currently, those are perl5.8.x and perl5.6.x, respectively.
+
+Beyond that, you have to consider several things and decide which is best
+for you.
+
+=over 4
+
+=item *
+
+If things aren't broken, upgrading perl may break them (or at least issue
+new warnings).
+
+=item *
+
+The latest versions of perl have more bug fixes.
+
+=item *
+
+The Perl community is geared toward supporting the most recent releases,
+so you'll have an easier time finding help for those.
+
+=item *
+
+Versions prior to perl5.004 had serious security problems with buffer
+overflows, and in some cases have CERT advisories (for instance,
+http://www.cert.org/advisories/CA-1997-17.html ).
+
+=item *
+
+The latest versions are probably the least deployed and widely tested, so
+you may want to wait a few months after their release and see what
+problems others have if you are risk averse.
+
+=item *
+
+The immediate, previous releases (i.e. perl5.6.x ) are usually maintained
+for a while, although not at the same level as the current releases.
+
+=item *
+
+No one is actively supporting perl4.x. Five years ago it was a dead
+camel carcass (according to this document). Now it's barely a skeleton
+as its whitewashed bones have fractured or eroded.
+
+=item *
+
+There is no perl6.x for the next couple of years. Stay tuned, but don't
+worry that you'll have to change major versions of Perl soon (i.e. before
+2008).
+
+=item *
+
+There are really two tracks of perl development: a maintenance version
+and an experimental version. The maintenance versions are stable, and
+have an even number as the minor release (i.e. perl5.8.x, where 8 is the
+minor release). The experimental versions may include features that
+don't make it into the stable versions, and have an odd number as the
+minor release (i.e. perl5.9.x, where 9 is the minor release).
+
+=back
+
+
+=head2 What are perl4, perl5, or perl6?
+
+(contributed by brian d foy)
+
+In short, perl4 is the past, perl5 is the present, and perl6 is the
+future.
+
+The number after perl (i.e. the 5 after perl5) is the major release
+of the perl interpreter as well as the version of the language. Each
+major version has significant differences that earlier versions cannot
+support.
+
+The current major release of Perl is perl5, and was released in 1994.
+It can run scripts from the previous major release, perl4 (March 1991),
+but has significant differences. It introduced the concept of references,
+complex data structures, and modules. The perl5 interpreter was a
+complete re-write of the previous perl sources.
+
+Perl6 is the next major version of Perl, but it's still in development
+in both its syntax and design. The work started in 2002 and is still
+ongoing. Many of the most interesting features have shown up in the
+latest versions of perl5, and some perl5 modules allow you to use some
+perl6 syntax in your programs. You can learn more about perl6 at
+http://dev.perl.org/perl6/ .
See L<perlhist> for a history of Perl revisions.
=head2 What is Ponie?
-At The O'Reilly Open Source Software Convention in 2003, Artur
-Bergman, Fotango, and The Perl Foundation announced a project to
-run perl5 on the Parrot virtual machine named Ponie. Ponie stands for
-Perl On New Internal Engine. The Perl 5.10 language implementation
-will be used for Ponie, and there will be no language level
-differences between perl5 and ponie. Ponie is not a complete rewrite
-of perl5.
+(contributed by brian d foy)
+
+Ponie stands for "Perl On the New Internal Engine", started by Arthur
+Bergman from Fotango in 2003, and subsequently run as a project of The
+Perl Foundation. Instead of using the current Perl internals, Ponie
+creates a new one that provides a translation path from Perl 5 to Perl 6
+(or anything else that targets Parrot, actually). You can also just keep
+using Perl 5 with Parrot, the virtual machine which will compile and run
+Perl 6 bytecode.
+
+You can get more information at http://www.poniecode.org/ and
+http://www.parrotcode.org .
=head2 What is perl6?
set of tasks. These languages have their own newsgroups in which you
can learn about (but hopefully not argue about) them.
-Some comparison documents can be found at http://language.perl.com/versus/
+Some comparison documents can be found at http://www.perl.com/doc/FMTEYEWTK/versus/
if you really can't stop yourself.
=head2 Can I do [task] in Perl?
=head2 What is a JAPH?
-These are the "just another perl hacker" signatures that some people
-sign their postings with. Randal Schwartz made these famous. About
-100 of the earlier ones are available from
-http://www.cpan.org/misc/japh .
+(contributed by brian d foy)
+
+JAPH stands for "Just another Perl hacker,", which Randal Schwartz used
+to sign email and usenet messages starting in the late 1980s. He
+previously used the phrase with many subjects ("Just another x hacker,"),
+so to distinguish his JAPH, he started to write them as Perl programs:
+
+ print "Just another Perl hacker,";
+
+Note the trailing comma and space, which allows the addition of other
+JAxH clauses for his many other interests.
+
+Other people picked up on this and started to write clever or obfuscated
+programs to produce the same output, spinning things quickly out of
+control while still providing hours of amusement for their creators and
+readers.
+
+CPAN has several JAPH programs at http://www.cpan.org/misc/japh .
=head2 Where can I get a list of Larry Wall witticisms?
-Over a hundred quips by Larry, from postings of his or source code,
-can be found at http://www.cpan.org/misc/lwall-quotes.txt.gz .
-
-=head2 How can I convince my sysadmin/supervisor/employees to use version 5/5.6.1/Perl instead of some other language?
-
-If your manager or employees are wary of unsupported software, or
-software which doesn't officially ship with your operating system, you
-might try to appeal to their self-interest. If programmers can be
-more productive using and utilizing Perl constructs, functionality,
-simplicity, and power, then the typical manager/supervisor/employee
-may be persuaded. Regarding using Perl in general, it's also
-sometimes helpful to point out that delivery times may be reduced
-using Perl compared to other languages.
-
-If you have a project which has a bottleneck, especially in terms of
-translation or testing, Perl almost certainly will provide a viable,
-quick solution. In conjunction with any persuasion effort, you
-should not fail to point out that Perl is used, quite extensively, and
-with extremely reliable and valuable results, at many large computer
-software and hardware companies throughout the world. In fact,
-many Unix vendors now ship Perl by default. Support is usually
-just a news-posting away, if you can't find the answer in the
-I<comprehensive> documentation, including this FAQ.
-
-See http://www.perl.org/advocacy/ for more information.
-
-If you face reluctance to upgrading from an older version of perl,
-then point out that version 4 is utterly unmaintained and unsupported
-by the Perl Development Team. Another big sell for Perl5 is the large
-number of modules and extensions which greatly reduce development time
-for any given task. Also mention that the difference between version
-4 and version 5 of Perl is like the difference between awk and C++.
-(Well, OK, maybe it's not quite that distinct, but you get the idea.)
-If you want support and a reasonable guarantee that what you're
-developing will continue to work in the future, then you have to run
-the supported version. As of October 2003 that means running either
-5.8.1 (released in September 2003), or one of the older releases like
-5.6.1 (released in April 2001) or 5.005_03 (released in March 1999),
-although 5.004_05 isn't that bad if you B<absolutely> need such an old
-version (released in April 1999) for stability reasons.
-Anything older than 5.004_05 shouldn't be used.
-
-Of particular note is the massive bug hunt for buffer overflow
-problems that went into the 5.004 release. All releases prior to
-that, including perl4, are considered insecure and should be upgraded
-as soon as possible.
-
-In August 2000 in all Linux distributions a new security problem was
-found in the optional 'suidperl' (not built or installed by default)
-in all the Perl branches 5.6, 5.005, and 5.004, see
-http://www.cpan.org/src/5.0/sperl-2000-08-05/
-Perl maintenance releases 5.6.1 and 5.8.0 have this security hole closed.
-Most, if not all, Linux distribution have patches for this
-vulnerability available, see http://www.linuxsecurity.com/advisories/ ,
-but the most recommendable way is to upgrade to at least Perl 5.6.1.
+(contributed by brian d foy)
+
+Google "larry wall quotes"! You might even try the "I feel lucky" button.
+:)
+
+Wikiquote has the witticisms from Larry along with their source,
+including his usenet postings and source code comments.
+
+If you want a plain text file, try
+http://www.cpan.org/misc/lwall-quotes.txt.gz .
+
+=head2 How can I convince others to use Perl?
+
+(contributed by brian d foy)
+
+Appeal to their self interest! If Perl is new (and thus scary) to them,
+find something that Perl can do to solve one of their problems. That
+might mean that Perl either saves them something (time, headaches, money)
+or gives them something (flexibility, power, testability).
+
+In general, the benefit of a language is closely related to the skill of
+the people using that language. If you or your team can be more faster,
+better, and stronger through Perl, you'll deliver more value. Remember,
+people often respond better to what they get out of it. If you run
+into resistance, figure out what those people get out of the other
+choice and how Perl might satisfy that requirement.
+
+You don't have to worry about finding or paying for Perl; it's freely
+available and several popular operating systems come with Perl. Community
+support in places such as Perlmonks ( http://www.perlmonks.com )
+and the various Perl mailing lists ( http://lists.perl.org ) means that
+you can usually get quick answers to your problems.
+
+Finally, keep in mind that Perl might not be the right tool for every
+job. You're a much better advocate if your claims are reasonable and
+grounded in reality. Dogmatically advocating anything tends to make
+people discount your message. Be honest about possible disadvantages
+to your choice of Perl since any choice has trade-offs.
+
+You might find these links useful:
+
+=over 4
+
+=item * http://perltraining.com.au/whyperl.html
+
+=item * http://www.perl.org/advocacy/whyperl.html
+
+=back
+
+=head1 REVISION
+
+Revision: $Revision: 3606 $
+
+Date: $Date: 2006-03-06 12:05:47 +0100 (lun, 06 mar 2006) $
+
+See L<perlfaq> for source control details and availability.
=head1 AUTHOR AND COPYRIGHT
-Copyright (c) 1997, 1998, 1999, 2000, 2001 Tom Christiansen and Nathan
-Torkington. All rights reserved.
+Copyright (c) 1997-2006 Tom Christiansen, Nathan Torkington, and
+other authors as noted. All rights reserved.
This documentation is free; you can redistribute it and/or modify it
under the same terms as Perl itself.
projects / p5sagit/p5-mst-13.2.git / blobdiff