Perl

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Table of Contents [show]     1 Introduction     2 Why is perl so popular     3 Can't locate object method X via package Y     4 Deepcloning object?     5 Unicode support     6 How do I call static methods in a package?     7 How do I configure Perl CPAN to use my proxy settings (especially on windows) Keywords BASIC, C, CPAN, Comprehensive Perl Archive Network, Larry Wall, MySQL, Oracle, PostgreSQL, SQL Server, Sybase, awk, object-oriented programming, procedural programming, sed, sh Copyright Information This article is licensed under GNU Public License. Contact webmasters for more information on copyright issues. 1 Introduction Perl is short for "Perfecf extraction and reporting language". Perl is cross platform because it's an interpretive language. You could run perl on any platform as long as you have a perl interpreter. Perl is not supported by all major operating systems including Windows, *nix, and Macintosh. Perl is open-source free software and it is licensed under its artistic license, or the GPL license. Perl was created by Larry Wall and Perl 1.0 was released to usenet's alt.comp.sources in 1987. 2 Why is perl so popular First and most importantly, Perl is an excellent programming language combining all the good stuff from C, awk, sed, sh, and BASIC. In its early years, tt made the life of unix system administrators a lot easier. Later on, with the Internet boom, Perl became more popular because of its powerful test information processing ability, which makes it an excellent language for web programming. Also, Perl supports all major databases including SQL Server, Oracle,MySQL, PostgreSQL, Sybase and others. Perl supports both procedural programming and object-oriented programming. Perl is extensible. It can be extended by third party modules. Currently there are over 500 third party modules available from the Comprehensive Perl Archive Network (CPAN). # The Perl interpreter can be embedded into other systems. 3 Can't locate object method X via package Y check to make sure you've got the correct class name and method name check to make sure you required or used the correct pm module In my case, perl didnot like my class name Config, when I changed it to ImageConfig.pm, everything went on well. I think Config must be some kind of pre-defined class or keyword in perl. 4 Deepcloning object? sub deep_copy { my $this = shift; if (not ref $this) { $this; } elsif (ref $this eq "ARRAY") { [map deep_copy($_), @$this]; } elsif (ref $this eq "HASH") { +{map { $_ => deep_copy($this->{$_}) } keys %$this}; } else { die "what type is $_?" } } Note that[SH] it will break if there are recursive data pointers. 5 Unicode support In perl 5.6.1, unicode support is " "incomplete" and "highly experimental"[SUN]. Perl 5.8 is supposed to have proper unicode support [PC] 6 How do I call static methods in a package? Use PackageA::PackageB::MethodName() instead of PackageA::PackageB->MethodName() 7 How do I configure Perl CPAN to use my proxy settings (especially on windows) cpan> o conf http_proxy http://proxy.xxx.com:3128 http_proxy http://proxy.xxx.com:3128 Please use 'o conf commit' to make the config permanent! cpan> o conf ftp_proxy http://proxy.xxx.com:3128 ftp_proxy http://proxy.xxx.com:3128 Please use 'o conf commit' to make the config permanent! cpan> o conf commit commit: wrote 'C:\Perl\lib/CPAN/Config.pm' Comments References [PC] http://www.perl.com/pub/a/2003/01/16/whatsnew.html [SH] http://www.stonehenge.com/merlyn/UnixReview/col30.html [SUN] http://developers.sun.com/dev/gadc/unicode/perl/perl561.html V.E.R.A Acronyms Pathologically Eclectic Rubbish Lister (slang) (search time: 0.964 msec) City Data Perla town, Arkansas: Check out what google has to say about Perla town, Arkansas Total households 56, total housing units: 67 Land area: 0.638832 square miles, water area 0.000000 miles Latitude: NORTH 34.364535, longitude: EAST -92.77877 MAP Population:115, male 54 female 61 Races in Perla town, Arkansas: Black (63.48%) White/Non-Hispanic (36.52%): Perley, Minnesota: Check out what google has to say about Perley, Minnesota Total households 53, total housing units: 61 Land area: 0.241336 square miles, water area 0.000000 miles Latitude: NORTH 47.177044, longitude: EAST -96.80298 MAP Population:121, male 61 female 60 Races in Perley, Minnesota: White/Non-Hispanic (87.60%): San Perlita, Texas: Check out what google has to say about San Perlita, Texas Total households 169, total housing units: 188 Land area: 0.507848 square miles, water area 0.000000 miles Latitude: NORTH 26.500515, longitude: EAST -97.64322 MAP Population:680, male 330 female 350 Races in San Perlita, Texas: Hispanic (88.53%) White/Non-Hispanic (9.56%) Black (2.21%): (search time: -329.199 msec)