NAME Syntax::Collector - collect a bundle of modules into one SYNOPSIS In lib/Example/ProjectX/Syntax.pm package Example::ProjectX::Syntax; use 5.010; our $VERSION = 1; use Syntax::Collector -collect => q/ use strict 0; use warnings 0; use feature 0 ':5.10'; use Scalar::Util 1.21 qw(blessed); /; 1; __END__ In projectx.pl: #!/usr/bin/perl use Example::ProjectX::Database; use Example::ProjectX::Syntax 1; # strict, warnings, feature ':5.10', etc are now enabled! say "Welcome to ProjectX"; DESCRIPTION Perl is such a flexible language that the language itself can be extended from within. (Though much of the more interesting stuff needs XS hooks like Devel::Declare.) One problem with this is that it often requires a lot of declarations at the top of your code, loading various syntax extensions. The syntax module on CPAN addresses this somewhat by allowing you to load a bunch of features in one line, provided each syntax feature implements the necessary API: use syntax qw/io maybe perform/; However this introduces problems of its own. If we look at the code above, it is non-obvious that it requires Syntax::Feature::Io, Syntax::Feature::Maybe and Syntax::Feature::Perform, which makes it difficult for automated tools such as Module::Install to automatically calculate your code's dependencies. Syntax::Collector to the rescue! package Example::ProjectX::Syntax; use 5.010; use Syntax::Collector -collect => q/ use strict 0; use warnings 0; use feature 0 ':5.10'; use Scalar::Util 1.21 qw(blessed); /; When you "use Syntax::Collector", you provide a list of modules to "collect" into a single package (notice the "q/.../"). This list of modules looks like a big string of Perl code that is going to be passed to "eval", but don't let that fool you - it is not. Each line must conform to the following pattern: (use|no) MODULENAME VERSION (OTHERSTUFF)? ; (Actually hash comments, and blank lines are also allowed.) The semantics of all that is pretty much what you'd expect, except that when MODULENAME begins with "Syntax::Feature::" it's treated with some DWIMmery, and "install" is called instead of "import". Note that VERSION is required, but if you don't care which version of a module you use, it's fine to set VERSION to 0. (Yes, VERSION is even required for pragmata.) Now, you ask... why stuff all that structured data into a string, and parse it out again? Because to naive lexical analysis (e.g. Module::Install) it really looks like a bunch of "use" lines, and not just a single quoted string. This helps tools calculate the dependencies of your collection; and thus the dependencies of other code that uses your collection. Because Syntax::Collector provides an "import" method for your collection package, you cannot provide your own. However, the "import" method provided will automatically call an "IMPORT" method if it exists. "IMPORT" is passed a copy of the same arguments that were passed to "import". (And indeed, it is invoked using "goto" so it should be safe to check caller(0).) As well as providing an "import" method for your collection, Syntax::Collector also provides a "modules" method, which can be called to find out which modules a collection includes. Called in list context, it returns a list. Called in scalar context, it returns a reference to a "{ module => version }" hash. A SYNTAX COLLECTION AND A UTILS COLLECTION Your project's syntax module is also a natural place to keep any frequently used utility functions, constants, etc. Thanks to the "IMPORT" method described above you can easily export these to the caller's namespace. Using with Sub::Exporter Sub::Exporter has an awesome feature set, so it is better than Exporter.pm. package Example::ProjectX::Syntax; our $VERSION = 1; use Syntax::Collector -collect => q/ use strict 0; use warnings 0; use feature 0 ':5.10'; use Scalar::Util 1.21 qw(blessed); /; use Sub::Exporter (); my $IMPORT = Sub::Exporter::build_exporter({ exports => [qw(true false)], groups => { booleans => [qw(true false)] }, }); sub IMPORT { goto $IMPORT; } sub true () { !!1 } sub false () { !!0 } 1; Using with Exporter.pm Exporter.pm comes bundled with Perl, so it is better than Sub::Exporter. package Example::ProjectX::Syntax; our $VERSION = 1; use Syntax::Collector -collect => q/ use strict 0; use warnings 0; use feature 0 ':5.10'; use Scalar::Util 1.21 qw(blessed); /; use Exporter (); our @EXPORT_OK = qw( true false ); our %EXPORT_TAGS = ( booleans => [qw( true false )], ); sub IMPORT { goto &Exporter::import; } sub true () { !!1 } sub false () { !!0 } 1; CAVEATS You should not rely on the "use" lines being processed in any particular order. BUGS Please report any bugs to . SEE ALSO syntax, Sub::Exporter. AUTHOR Toby Inkster . COPYRIGHT AND LICENCE This software is copyright (c) 2012 by Toby Inkster. This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself. DISCLAIMER OF WARRANTIES THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.