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Diffstat (limited to 'pod/perlfaq3.pod')
| -rw-r--r-- | pod/perlfaq3.pod | 111 |
1 files changed, 72 insertions, 39 deletions
diff --git a/pod/perlfaq3.pod b/pod/perlfaq3.pod index 7a307594da..31e669fd5d 100644 --- a/pod/perlfaq3.pod +++ b/pod/perlfaq3.pod @@ -13,10 +13,13 @@ Have you looked at CPAN (see L<perlfaq2>)? The chances are that someone has already written a module that can solve your problem. Have you read the appropriate man pages? Here's a brief index: + Basics perldata, perlvar, perlsyn, perlop, perlsub + Execution perlrun, perldebug + Functions perlfunc Objects perlref, perlmod, perlobj, perltie Data Structures perlref, perllol, perldsc Modules perlmod, perlmodlib, perlsub - Regexps perlre, perlfunc, perlop + Regexps perlre, perlfunc, perlop, perllocale Moving to perl5 perltrap, perl Linking w/C perlxstut, perlxs, perlcall, perlguts, perlembed Various http://www.perl.com/CPAN/doc/FMTEYEWTK/index.html @@ -65,8 +68,8 @@ breakdowns of where your code spends its time. =head2 How do I cross-reference my Perl programs? The B::Xref module, shipped with the new, alpha-release Perl compiler -(not the general distribution), can be used to generate -cross-reference reports for Perl programs. +(not the general distribution prior to the 5.005 release), can be used +to generate cross-reference reports for Perl programs. perl -MO=Xref[,OPTIONS] foo.pl @@ -99,10 +102,10 @@ the trick. =head2 Where can I get Perl macros for vi? For a complete version of Tom Christiansen's vi configuration file, -see ftp://ftp.perl.com/pub/vi/toms.exrc, the standard benchmark file -for vi emulators. This runs best with nvi, the current version of vi -out of Berkeley, which incidentally can be built with an embedded Perl -interpreter -- see http://www.perl.com/CPAN/src/misc . +see http://www.perl.com/CPAN/authors/Tom_Christiansen/scripts/toms.exrc, +the standard benchmark file for vi emulators. This runs best with nvi, +the current version of vi out of Berkeley, which incidentally can be built +with an embedded Perl interpreter -- see http://www.perl.com/CPAN/src/misc. =head2 Where can I get perl-mode for emacs? @@ -121,25 +124,23 @@ should be using "main::foo", anyway. =head2 How can I use curses with Perl? The Curses module from CPAN provides a dynamically loadable object -module interface to a curses library. +module interface to a curses library. A small demo can be found at the +directory http://www.perl.com/CPAN/authors/Tom_Christiansen/scripts/rep; +this program repeats a command and updates the screen as needed, rendering +B<rep ps axu> similar to B<top>. =head2 How can I use X or Tk with Perl? -Tk is a completely Perl-based, object-oriented interface to the Tk -toolkit that doesn't force you to use Tcl just to get at Tk. Sx is an -interface to the Athena Widget set. Both are available from CPAN. +Tk is a completely Perl-based, object-oriented interface to the Tk toolkit +that doesn't force you to use Tcl just to get at Tk. Sx is an interface +to the Athena Widget set. Both are available from CPAN. See the +directory http://www.perl.com/CPAN/modules/by-category/08_User_Interfaces/ =head2 How can I generate simple menus without using CGI or Tk? The http://www.perl.com/CPAN/authors/id/SKUNZ/perlmenu.v4.0.tar.gz module, which is curses-based, can help with this. -=head2 Can I dynamically load C routines into Perl? - -If your system architecture supports it, then the standard perl -on your system should also provide you with this via the -DynaLoader module. Read L<perlxstut> for details. - =head2 What is undump? See the next questions. @@ -225,9 +226,9 @@ No, Perl's garbage collection system takes care of this. =head2 How can I free an array or hash so my program shrinks? -You can't. Memory the system allocates to a program will never be -returned to the system. That's why long-running programs sometimes -re-exec themselves. +You can't. Memory the system allocates to a program will in practice +never be returned to the system. That's why long-running programs +sometimes re-exec themselves. However, judicious use of my() on your variables will help make sure that they go out of scope so that Perl can free up their storage for @@ -266,6 +267,8 @@ Both of these solutions can have far-reaching effects on your system and on the way you write your CGI scripts, so investigate them with care. +See http://www.perl.com/CPAN/modules/by-category/15_World_Wide_Web_HTML_HTTP_CGI/. + =head2 How can I hide the source for my Perl program? Delete it. :-) Seriously, there are a number of (mostly @@ -319,9 +322,10 @@ save little more than compilation time, leaving execution no more than (like several times faster), but this takes some tweaking of your code. -Malcolm will be in charge of the 5.005 release of Perl itself -to try to unify and merge his compiler and multithreading work into -the main release. +The 5.005 release of Perl itself, whose main goal is merging the various +non-Unix ports back into the one Perl source, will also have preliminary +(strictly beta) support for Malcolm's compiler and his light-weight +processes (sometimes called "threads"). You'll probably be astonished to learn that the current version of the compiler generates a compiled form of your script whose executable is @@ -334,6 +338,16 @@ you link your main perl binary with this, it will make it miniscule. For example, on one author's system, /usr/bin/perl is only 11k in size! +In general, the compiler will do nothing to make a Perl program smaller, +faster, more portable, or more secure. In fact, it will usually hurt +all of those. The executable will be bigger, your VM system may take +longer to load the whole thing, the binary is fragile and hard to fix, +and compilation never stopped software piracy in the form of crackers, +viruses, or bootleggers. The real advantage of the compiler is merely +packaging, and once you see the size of what it makes (well, unless +you use a shared I<libperl.so>), you'll probably want a complete +Perl install anywayt. + =head2 How can I get '#!perl' to work on [MS-DOS,NT,...]? For OS/2 just use @@ -365,12 +379,12 @@ Yes. Read L<perlrun> for more information. Some examples follow. (These assume standard Unix shell quoting rules.) # sum first and last fields - perl -lane 'print $F[0] + $F[-1]' + perl -lane 'print $F[0] + $F[-1]' * # identify text files perl -le 'for(@ARGV) {print if -f && -T _}' * - # remove comments from C program + # remove (most) comments from C program perl -0777 -pe 's{/\*.*?\*/}{}gs' foo.c # make file a month younger than today, defeating reaper daemons @@ -433,21 +447,28 @@ books. For problems and questions related to the web, like "Why do I get 500 Errors" or "Why doesn't it run from the browser right when it runs fine on the command line", see these sources: - The Idiot's Guide to Solving Perl/CGI Problems, by Tom Christiansen - http://www.perl.com/perl/faq/idiots-guide.html + WWW Security FAQ + http://www.w3.org/Security/Faq/ - Frequently Asked Questions about CGI Programming, by Nick Kew - ftp://rtfm.mit.edu/pub/usenet/news.answers/www/cgi-faq - http://www3.pair.com/webthing/docs/cgi/faqs/cgifaq.shtml + Web FAQ + http://www.boutell.com/faq/ - Perl/CGI programming FAQ, by Shishir Gundavaram and Tom Christiansen - http://www.perl.com/perl/faq/perl-cgi-faq.html + CGI FAQ + http://www.webthing.com/page.cgi/cgifaq - The WWW Security FAQ, by Lincoln Stein - http://www-genome.wi.mit.edu/WWW/faqs/www-security-faq.html + HTTP Spec + http://www.w3.org/pub/WWW/Protocols/HTTP/ + + HTML Spec + http://www.w3.org/TR/REC-html40/ + http://www.w3.org/pub/WWW/MarkUp/ + + CGI Spec + http://www.w3.org/CGI/ + + CGI Security FAQ + http://www.go2net.com/people/paulp/cgi-security/safe-cgi.txt - World Wide Web FAQ, by Thomas Boutell - http://www.boutell.com/faq/ =head2 Where can I learn about object-oriented Perl programming? @@ -499,6 +520,18 @@ information, see L<ExtUtils::MakeMaker>. =head1 AUTHOR AND COPYRIGHT -Copyright (c) 1997 Tom Christiansen and Nathan Torkington. -All rights reserved. See L<perlfaq> for distribution information. - +Copyright (c) 1997, 1998 Tom Christiansen and Nathan Torkington. +All rights reserved. + +When included as part of the Standard Version of Perl, or as part of +its complete documentation whether printed or otherwise, this work +may be distributed only under the terms of Perl's Artistic License. +Any distribution of this file or derivatives thereof I<outside> +of that package require that special arrangements be made with +copyright holder. + +Irrespective of its distribution, all code examples in this file +are hereby placed into the public domain. You are permitted and +encouraged to use this code in your own programs for fun +or for profit as you see fit. A simple comment in the code giving +credit would be courteous but is not required. |