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Chapter 12 Packages, Libraries, and Modules |
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Perl is shipped with many modules. Even more can be found on CPAN. The following program prints out the names, versions, and descriptions of all modules installed on your system. It uses standard modules like File::Find and includes several techniques described in this chapter.
To run it, type:
% pmdesc
It prints a list of modules and their descriptions:
FileHandle (2.00) - supply object methods for filehandlesIO::File (1.06021) - supply object methods for filehandlesIO::Select (1.10) - OO interface to the select system call...IO::Socket (1.1603) - Object interface to socket communications
With the -v flag, pmdesc provides the names of the directories the files are in:
% pmdesc -v<<<Modules from /usr/lib/perl5/i686-linux/5.00404>>>...FileHandle (2.00) - supply object methods for filehandles
The -w flag warns if a module doesn't come with a pod description, and -s sorts the module list within each directory.
The program is given in Example 12.3 .
#!/usr/bin/perl -w # pmdesc - describe pm files # [email protected] use strict; use File::Find qw(find); use Getopt::Std qw(getopts); use Carp; use vars ( q!$opt_v!, # give debug info q!$opt_w!, # warn about missing descs on modules q!$opt_a!, # include relative paths q!$opt_s!, # sort output within each directory ); $| = 1; getopts('wvas') or die "bad usage"; @ARGV = @INC unless @ARGV; # Globals. wish I didn't really have to do this. use vars ( q!$Start_Dir!, # The top directory find was called with q!%Future!, # topdirs find will handle later ); my $Module; # install an output filter to sort my module list, if wanted. if ($opt_s) { if (open(ME, "-|")) { $/ = ''; while (<ME>) { chomp; print join("\n", sort split /\n/), "\n"; } exit; } } MAIN: { my %visited; my ($dev,$ino); @Future{@ARGV} = (1) x @ARGV; foreach $Start_Dir (@ARGV) { delete $Future{$Start_Dir}; print "\n<<Modules from $Start_Dir>>\n\n" if $opt_v; next unless ($dev,$ino) = stat($Start_Dir); next if $visited{$dev,$ino}++; next unless $opt_a || $Start_Dir =~ m!^/!; find(\&wanted, $Start_Dir); } exit; } # calculate module name from file and directory sub modname { local $_ = $File::Find::name; if (index($_, $Start_Dir . '/') == 0) { substr($_, 0, 1+length($Start_Dir)) = ''; } s { / } {::}gx; s { \.p(m|od)$ } {}x; return $_; } # decide if this is a module we want sub wanted { if ( $Future{$File::Find::name} ) { warn "\t(Skipping $File::Find::name, qui venit in futuro.)\n" if 0 and $opt_v; $File::Find::prune = 1; return; } return unless /\.pm$/ && -f; $Module = &modname; # skip obnoxious modules if ($Module =~ /^CPAN(\Z|::)/) { warn("$Module -- skipping because it misbehaves\n"); return; } my $file = $_; unless (open(POD, "< $file")) { warn "\tcannot open $file: $!"; # if $opt_w; return 0; } $: = " -:"; local $/ = ''; local $_; while (<POD>) { if (/=head\d\s+NAME/) { chomp($_ = <POD>); s/^.*?-\s+//s; s/\n/ /g; #write; my $v; if (defined ($v = getversion($Module))) { print "$Module ($v) "; } else { print "$Module "; } print "- $_\n"; return 1; } } warn "\t(MISSING DESC FOR $File::Find::name)\n" if $opt_w; return 0; } # run Perl to load the module and print its verson number, redirecting # errors to /dev/null sub getversion { my $mod = shift; my $vers = `$^X -m$mod -e 'print \$${mod}::VERSION' 2>/dev/null`; $vers =~ s/^\s*(.*?)\s*$/$1/; # remove stray whitespace return ($vers || undef); } format = ^<<<<<<<<<<<<<<<<<~~^<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< $Module, $_ .
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| 12.18. Example: Module Template |
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13. Classes, Objects, and Ties |
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