NAME
    Ref::Util - Utility functions for checking references

DESCRIPTION
    Ref::Util introduces several functions to help identify references in a
    faster and smarter way. In short:

        ref $foo eq 'ARRAY'

        # is now:

        is_arrayref($foo)

    The difference:

    *   No comparison against a string constant

        When you call "ref", you stringify the reference and then compare it
        to some string constant (like "ARRAY" or "HASH"). Not just awkward,
        it's brittle since you can mispell the string.

    *   Supports blessed variables

        When calling "ref", you receive either the reference type (SCALAR,
        ARRAY, HASH, etc.) or the package it's blessed into.

        When calling "is_arrayref" (et. al.), you check the variable flags,
        so even if it's blessed, you know what type of variable is blessed.

            my $foo = bless {}, 'PKG';
            ref($foo) eq 'HASH'; # fails

            use Ref::Util 'is_hashref';
            my $foo = bless {}, 'PKG';
            is_hashref($foo); # works

    *   Supports overloaded variables

        If you've overloaded anything ("eq", stringification), you will
        probably get bitten. However, these functions do not care since they
        only check flags.

    Additionally, two implementations are available, depending on the perl
    version you have. For perl that supports Custom OPs, we actually add an
    OP code (which is faster), and for perls that do not, we include an
    implementation that just calls an XS function - which is still faster
    than the Pure-Perl equivalent.

    We might also introduce a Pure-Perl version of everything, allowing to
    install this module where a compiler is not available, making the XS
    parts optional.

SUBROUTINES
  is_scalarref($ref)
    Check for a scalar reference.

        is_scalarref(\"hello");
        is_scalarref(\30);
        is_scalarref(\$value);

  is_arrayref($ref)
    Check for an array reference.

        is_arrayref([]);

  is_hashref($ref)
    Check for a hash reference.

        is_hashref({});

  is_coderef($ref)
    Check for a code reference.

        is_coderef( sub {} );

  is_regexpref($ref)
    Check for a regular expression (regex, regexp) reference.

        is_regexpref( qr// );

  is_globref($ref)
    Check for a glob reference.

        is_globref( \*STDIN );

  is_formatref($ref)
    Check for a format reference.

        # set up format in STDOUT
        format STDOUT =
        .

        # now we can test it
        is_formatref( *main::STDOUT{'FORMAT'} );

  is_ioref($ref)
    Check for an IO reference.

        is_ioref( *STDOUT{IO} );

SEE ALSO
    *   Params::Classify

THANKS
    The following people have been invaluable in their feedback and support.

    *   Yves Orton

    *   Steffen Müller

    *   Jarkko Hietaniemi

    *   Mattia Barbon

AUTHORS
    *   Vikentiy Fesunov

    *   Sawyer X

    *   Gonzalo Diethelm

    *   p5pclub

