NAME
    Module::Installed::Tiny - Check if a module is installed, with as little
    code as possible

VERSION
    This document describes version 0.006 of Module::Installed::Tiny (from
    Perl distribution Module-Installed-Tiny), released on 2022-06-10.

SYNOPSIS
     use Module::Installed::Tiny qw(module_installed module_source);

     # check if a module is available
     if (module_installed "Foo::Bar") {
         # Foo::Bar is available
     } elsif (module_installed "Foo/Baz.pm") {
         # Foo::Baz is available
     }

     # get a module's source code, dies on failure
     my $src = module_source("Foo/Baz.pm");

DESCRIPTION
    To check if a module is installed (available), generally the simplest
    way is to try to "require()" it:

     if (eval { require Foo::Bar; 1 }) {
         # Foo::Bar is available
     }

    However, this actually loads the module. There are some cases where this
    is not desirable: 1) we have to check a lot of modules (actually loading
    the modules will take a lot of CPU time and memory; 2) some of the
    modules conflict with one another and cannot all be loaded; 3) the
    module is OS specific and might not load under another OS; 4) we simply
    do not want to execute the module, for security or other reasons.

    "Module::Installed::Tiny" provides a routine "module_installed()" which
    works like Perl's "require" but does not actually load the module.

    This module does not require any other module except Exporter.

FUNCTIONS
  module_installed
    Usage:

     module_installed($name [ , \%opts ]) => bool

    Check that module named $name is available to load. This means that:
    either the module file exists on the filesystem and searchable in @INC
    and the contents of the file can be retrieved, or when there is a
    require hook in @INC, the module's source can be retrieved from the
    hook.

    Note that this does not guarantee that the module can eventually be
    loaded successfully, as there might be syntax or runtime errors in the
    module's source. To check for that, one would need to actually load the
    module using "require".

    Options:

    *

  module_source
    Usage:

     module_source($name [ , \%opts ]) => str | (str, source_name)

    Return module's source code, without actually loading it. Die on failure
    (e.g. module named $name not found in @INC).

    In list context:

     my @res = module_source($name);

    will return the list:

     (str, source_name)

    where "str" is the module source code and "source_name" is source
    information (file path, or the @INC ref entry when entry is a ref).

    Options:

    *   die

        Bool. Default true. If set to false, won't die upon failure but
        instead will return undef (or empty list in list context).

    *   find_prefix

        Bool. If set to true, when a module (e.g. "Foo/Bar.pm") is not found
        in the fileysstem but its directory is ("Foo/Bar/"), then instead of
        dying or returning undef/empty list, the function will return:

         \$path

        in scalar context, or:

         (undef, \$path)

        in list context.

FAQ
  How to get module source without dying? I want to just get undef if module source is not available.
    Wrap in "eval()" or "try/catch" (Perl 5.34+):

     my $src;
     eval { $src = module_source $name };
     # $src contains the module source or undef if not available

    This is what "module_installed()" does.

HOMEPAGE
    Please visit the project's homepage at
    <https://metacpan.org/release/Module-Installed-Tiny>.

SOURCE
    Source repository is at
    <https://github.com/perlancar/perl-Module-Installed-Tiny>.

SEE ALSO
    Module::Load::Conditional provides "check_install" which also does what
    "module_installed" does, plus can check module version. It also has a
    couple other knobs to customize its behavior. It's less tiny than
    Module::Installed::Tiny though.

    Module::Path and Module::Path::More. These modules can also be used to
    check if a module on the filesystem is available. They do not handle
    require hooks, nor do they actually check that the module file is
    readable.

AUTHOR
    perlancar <perlancar@cpan.org>

CONTRIBUTING
    To contribute, you can send patches by email/via RT, or send pull
    requests on GitHub.

    Most of the time, you don't need to build the distribution yourself. You
    can simply modify the code, then test via:

     % prove -l

    If you want to build the distribution (e.g. to try to install it locally
    on your system), you can install Dist::Zilla,
    Dist::Zilla::PluginBundle::Author::PERLANCAR, and sometimes one or two
    other Dist::Zilla plugin and/or Pod::Weaver::Plugin. Any additional
    steps required beyond that are considered a bug and can be reported to
    me.

COPYRIGHT AND LICENSE
    This software is copyright (c) 2022, 2021, 2020, 2016 by perlancar
    <perlancar@cpan.org>.

    This is free software; you can redistribute it and/or modify it under
    the same terms as the Perl 5 programming language system itself.

BUGS
    Please report any bugs or feature requests on the bugtracker website
    <https://rt.cpan.org/Public/Dist/Display.html?Name=Module-Installed-Tiny
    >

    When submitting a bug or request, please include a test-file or a patch
    to an existing test-file that illustrates the bug or desired feature.