=head1 NAME
-perlfaq1 - General Questions About Perl ($Revision: 1.5 $, $Date: 2002/01/27 20:22:52 $)
+perlfaq1 - General Questions About Perl ($Revision: 1.19 $, $Date: 2005/12/31 00:54:37 $)
=head1 DESCRIPTION
are a rag-tag band of highly altruistic individuals committed to
producing better software for free than you could hope to purchase for
money. You may snoop on pending developments via the archives at
-http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/
-and http://archive.develooper.com/perl5-porters@perl.org/
+http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/
+and http://archive.develooper.com/perl5-porters@perl.org/
or the news gateway nntp://nntp.perl.org/perl.perl5.porters or
its web interface at http://nntp.perl.org/group/perl.perl5.porters ,
-or read the faq at http://perlhacker.org/p5p-faq,
+or read the faq at http://simon-cozens.org/writings/p5p-faq ,
or you can subscribe to the mailing list by sending
perl5-porters-request@perl.org a subscription request
(an empty message with no subject is fine).
=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-no longer maintained; its last patch (4.036) was in 1992, long ago and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 5.6 (although 5.005_03 is still supported).
-The most cutting-edge development release is 5.7. 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 2006).
+
+=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.
+
+For more details, see http://www.poniecode.org/
+
=head2 What is perl6?
-At The Second O'Reilly Open Source Software Convention, Larry Wall
+At The Second O'Reilly Open Source Software Convention, Larry Wall
announced Perl6 development would begin in earnest. Perl6 was an oft
used term for Chip Salzenberg's project to rewrite Perl in C++ named
Topaz. However, Topaz provided valuable insights to the next version
-of Perl and its implementation, but was ultimately abandoned.
+of Perl and its implementation, but was ultimately abandoned.
-If you want to learn more about Perl6, or have a desire to help in
-the crusade to make Perl a better place then peruse the Perl6 developers
+If you want to learn more about Perl6, or have a desire to help in
+the crusade to make Perl a better place then peruse the Perl6 developers
page at http://dev.perl.org/perl6/ and get involved.
Perl6 is not scheduled for release yet, and Perl5 will still be supported
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?
can parse Perl." You may or may not choose to follow this usage. For
example, parallelism means "awk and perl" and "Python and Perl" look
OK, while "awk and Perl" and "Python and perl" do not. But never
-write "PERL", because perl isn't really an acronym, apocryphal
+write "PERL", because perl is not an acronym, apocryphal
folklore and post-facto expansions notwithstanding.
=head2 Is it a Perl program or a Perl script?
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 5/5.005/Perl instead of some other language?
+=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
(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 April 2001 that probably means
-running either of the releases 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.
+the supported version. As of December 2003 that means running either
+5.8.2 (released in November 2003), or one of the older releases like
+5.6.2 (also released in November 2003; a maintenance release to let perl
+5.6 compile on newer systems as 5.6.1 was 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
=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.
https://perl5.git.perl.org / perl5.git / blobdiff