Module::ScanDeps - Recursively scan Perl code for dependencies
This document describes version 0.54 of Module::ScanDeps, released January 11, 2005.
Via the command-line program scandeps.pl:
% scandeps.pl *.pm # Print PREREQ_PM section for *.pm
% scandeps.pl -e "use utf8" # Read script from command line
% scandeps.pl -B *.pm # Include core modules
% scandeps.pl -V *.pm # Show autoload/shared/data files
Used in a program;
# standard usage
my $hash_ref = scan_deps(
files => [ 'a.pl', 'b.pl' ],
recurse => 1,
# shorthand; assume recurse == 1
my $hash_ref = scan_deps( 'a.pl', 'b.pl' );
# App::Packer::Frontend compatible interface
# see App::Packer::Frontend for the structure returned by get_files
my $scan = Module::ScanDeps->new;
$scan->set_file( 'a.pl' );
$scan->set_options( add_modules => [ 'Test::More' ] );
my $files = $scan->get_files;
This module scans potential modules used by perl programs, and returns a hash reference; its keys are the module names as appears in %INC (e.g. Test/More.pm); the values are hash references with this structure:
file => '/usr/local/lib/perl5/5.8.0/Test/More.pm',
key => 'Test/More.pm',
type => 'module', # or 'autoload', 'data', 'shared'
used_by => [ 'Test/Simple.pm', ... ],
One function, scan_deps, is exported by default. Three other functions (scan_line, scan_chunk, add_deps) are exported upon request.
Users of App::Packer may also use this module as the dependency-checking frontend, by tweaking their p2e.pl like below:
my $packer = App::Packer->new( frontend => 'Module::ScanDeps' );
Please see App::Packer::Frontend for detailed explanation on the structure returned by get_files.
$rv_ref = scan_deps(
files => \@files, recurse => $recurse,
rv => \%rv, skip => \%skip,
compile => $compile, execute => $execute,
$rv_ref = scan_deps(@files); # shorthand, with recurse => 1
This function scans each file in @files, registering their dependencies into %rv, and returns a reference to the updated %rv. The meaning of keys and values are explained above.
If $recurse is true, scan_deps will call itself recursively, to perform a breadth-first search on text files (as defined by the -T operator) found in %rv.
If the \%skip is specified, files that exists as its keys are skipped. This is used internally to avoid infinite recursion.
If $compile or $execute is true, runs files in either compile-only or normal mode, then inspects their %INC after termination to determine additional runtime dependencies.
If $execute is an array reference, runs the files contained in it instead of @files.
Like scan_deps, but skips the static scanning part.
@modules = scan_line($line);
Splits a line into chunks (currently with the semicolon characters), and return the union of scan_chunk calls of them.
If the line is __END__ or __DATA__, a single __END__ element is returned to signify the end of the program.
Similarly, it returns a single __POD__ if the line matches /^=\w/; the caller is responsible for skipping appropriate number of lines until =cut, before calling scan_line again.
$module = scan_chunk($chunk);
@modules = scan_chunk($chunk);
Apply various heuristics to $chunk to find and return the module name(s) it contains. In scalar context, returns only the first module or undef.
$rv_ref = add_deps( rv => \%rv, modules => \@modules );
$rv_ref = add_deps( @modules ); # shorthand, without rv
Resolves a list of module names to its actual on-disk location, by finding in @INC; modules that cannot be found are skipped.
This function populates the %rv hash with module/filename pairs, and returns a reference to it.
This module intentially ignores the BSDPAN hack on FreeBSD -- the additional directory is removed from @INC altogether.
The static-scanning heuristic is not likely to be 100% accurate, especially on modules that dynamically load other modules.
Chunks that span multiple lines are not handled correctly. For example, this one works:
use base 'Foo::Bar';
But this one does not:
scandeps.pl is a bundled utility that writes PREREQ_PM section for a number of files.
An application of Module::ScanDeps is to generate executables from scripts that contains prerequisite modules; this module supports two such projects, PAR and App::Packer. Please see their respective documentations on CPAN for further information.
Audrey Tang <email@example.com>
Parts of heuristics were deduced from:
PerlApp by ActiveState Tools Corp http://www.activestate.com/
Perl2Exe by IndigoStar, Inc http://www.indigostar.com/
The scan_deps_runtime function is contributed by Edward S. Peschko.
http://par.perl.org/ is the official website for this module. You can write to the mailing list at <firstname.lastname@example.org>, or send an empty mail to <email@example.com> to participate in the discussion.
Please submit bug reports to <bug-Module-ScanDeps@rt.cpan.org>.
Copyright 2002, 2003, 2004, 2005, 2006 by Audrey Tang <firstname.lastname@example.org>.
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
To install Module::ScanDeps, copy and paste the appropriate command in to your terminal.
perl -MCPAN -e shell
For more information on module installation, please visit the detailed CPAN module installation guide.