Module::ScanDeps - Recursively scan Perl code for dependencies
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', ... ],
uses => [ 'Test/Other.pm', ... ],
One function, "scan_deps", is exported by default. Other functions
such as ("scan_line", "scan_chunk", "add_deps",
"path_to_inc_name") are exported upon request.
Users of App::Packer
may also use this module as the dependency-checking
frontend, by tweaking their p2e.pl
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 $execute is an array reference, passes @$execute as arguments to each file in
@files when it is run.
If performance of the scanning process is a concern, "cache_file" can
be set to a filename. The scanning results will be cached and written to the
file. This will speed up the scanning process on subsequent runs.
Additionally, an option "warn_missing" is recognized. If set to true,
"scan_deps" issues a warning to STDERR for every module file that
the scanned code depends but that wasn't found. Please note that this may also
report numerous false positives. That is why by default, the heuristic
silently drops all dependencies it cannot find.
, 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
$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 and @Module::ScanDeps::IncludeLibs; modules that cannot be found are
This function populates the %rv hash with module/filename pairs, and returns a
reference to it.
$perl_name = path_to_inc_name($path, $warn)
Assumes $path refers to a perl file and does it's best to return the name as it
would appear in %INC. Returns undef if no match was found and a prints a
warning to STDERR if $warn is true.
E.g. if $path = perl/site/lib/Module/ScanDeps.pm then $perl_name will be
You can set this global variable to specify additional directories in which to
search modules without modifying @INC itself.
You can set this global variable to specify a regular expression to identify
what files to scan. By default it includes all files of the following types:
.pm, .pl, .t and .al. Additionally, all files without a suffix are considered.
For instance, if you want to scan all files then use the following:
"$Module::ScanDeps::ScanFileRE = qr/./"
This module intentionally 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
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>
To a lesser degree: Steffen Mueller <firstname.lastname@example.org>
Parts of heuristics were deduced from:
- PerlApp by ActiveState Tools Corp
- Perl2Exe by IndigoStar, Inc <http://www.indigostar.com/>
function is contributed by Edward S. Peschko.
You can write to the mailing list at <email@example.com>, or send an empty mail
to <firstname.lastname@example.org> to participate in the discussion.
Please submit bug reports to <bug-Module-ScanDeps@rt.cpan.org>.
Copyright 2002-2008 by Audrey Tang <email@example.com>; 2005-2010 by
Steffen Mueller <firstname.lastname@example.org>.
This program is free software; you can redistribute it and/or modify it under
the same terms as Perl itself.