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Module::ScanDeps(3)   User Contributed Perl Documentation  Module::ScanDeps(3)

       Module::ScanDeps	- Recursively scan Perl	code for dependencies

       Via the command-line program

	   % *.pm	       # Print PREREQ_PM section for *.pm
	   % -e "use utf8" # Read script from command line
	   % -B *.pm       # Include core modules
	   % -V *.pm       # Show autoload/shared/data files

       Used in a program;

	   use Module::ScanDeps;

	   # standard usage
	   my $hash_ref	= scan_deps(
	       files   => [ '', '' ],
	       recurse => 1,

	   # shorthand;	assume recurse == 1
	   my $hash_ref	= scan_deps( '', '' );

	   # App::Packer::Frontend compatible interface
	   # see App::Packer::Frontend for the structure returned by get_files
	   my $scan = Module::ScanDeps->new;
	   $scan->set_file( '' );
	   $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/"); the values are hash references with this

	       file    => '/usr/local/lib/perl5/5.8.0/Test/',
	       key     => 'Test/',
	       type    => 'module',    # or 'autoload',	'data',	'shared'
	       used_by => [ 'Test/', ... ],
	       uses    => [ 'Test/', ... ],

       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 like	below:

	   use Module::ScanDeps;
	   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

       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.

       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 and @Module::ScanDeps::IncludeLibs; modules that	cannot
       be found	are skipped.

       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/	then $perl_name	will
       be Module/

       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 works:

	   use base 'Foo::Bar';

       But this	one does not:

	   use base

SEE ALSO 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.

       Other modules which accomplish the same goal with different approach:
       Module::ExtractUse, Perl::PrereqScanner,	Perl::PrereqScanner::Lite,

       Audrey Tang <>

       To a lesser degree: Steffen Mueller <>

       Parts of	heuristics were	deduced	from:

       o   PerlApp by ActiveState Tools	Corp <>

       o   Perl2Exe by IndigoStar, Inc <>

       The scan_deps_runtime function is contributed by	Edward S. Peschko.

       You can write to	the mailing list at <>, or send an empty
       mail to <>	to participate in the discussion.

       Please submit bug reports to <>.

       Copyright 2002-2008 by Audrey Tang <>; 2005-2010	by
       Steffen Mueller <>.

       This program is free software; you can redistribute it and/or modify it
       under the same terms as Perl itself.

       See <>

perl v5.32.1			  2021-04-21		   Module::ScanDeps(3)


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