Hash::Normalize - Automatically normalize Unicode hash keys.

    Version 0.01

        use Hash::Normalize qw<normalize>;

        normalize my %hash, 'NFC';

        $hash{café} = 'coffee'; # NFD, "cafe\x{301}"

        print $hash{café};      # NFD, "cafe\x{301}"
        # 'coffee' is printed

        print $hash{café};      # NFC, "caf\x{e9}"
        # 'coffee' is also printed

    This module provides an utility routine that augments a given Perl hash
    table so that its keys are automatically normalized following one of the
    Unicode normalization schemes. All the following actions on this hash
    will be made regardless of how the key used for the action is

    Since this module does not use the "tie" mechanism, normalized hashes
    are indistinguishable from regular hashes as far as Perl is concerned,
    but this module also provides "get_normalization" to identify them if

        normalize %hash;
        normalize %hash, $mode;

    Applies the Unicode normalization scheme $mode onto %hash. $mode
    defaults to 'NFC' if omitted, and should match
    "/^(?:(?:nf)?k?|fc)[cd]$/i" otherwise.

    "normalize" will first try to forcefully normalize the existing keys in
    %hash to the new mode, but it will throw an exception if there are
    distinct keys that have the same normalization. All the keys
    subsequently used for fetches, stores, exists, deletes and list
    assignments are then first passed through the according normalization
    procedure. "keys %hash" will also return the list of normalized keys.

        my $mode = get_normalization %hash;
        normalize %hash, $mode;

    Returns the current Unicode normalization scheme in use for %hash, or
    "undef" if it is a plain hash.

    Stashes (Perl symbol tables) are implemented as plain hashes, therefore
    one can use "normalize %Pkg::" on them to make sure that Unicode symbol
    lookups are made regardless of normalization.

        package Foo;

        BEGIN {
         require Hash::Normalize;
         # Enforce NFC normalization
         Hash::Normalize::normalize(%Foo::, 'NFC')

        sub café { # NFD, "cafe\x{301}"
         return 'coffee'

        sub coffee_nfc {
         café() # NFC, "cafe\x{e9}"

        sub coffee_nfd {
         café() # NFD, "cafe\x{301}"

        # Both coffee_nfc() and coffee_nfd() return 'coffee'

    Using a normalized hash is slightly slower than a plain hash, due to the
    normalization procedure and the overhead of magic.

    If a hash is initialized from a normalized hash by list assignment
    ("%new = %normalized"), then the normalization scheme will not be
    carried over to the new hash, although its keys will initially be
    normalized like the ones from the original hash.

    The functions "normalize" and "get_normalization" are only exported on
    request by specifying their names in the module import list.

    perl 5.10.

    Carp, Exporter (core since perl 5).

    Unicode::Normalize (core since perl 5.8).

    Variable::Magic 0.51.

    Vincent Pit, "<perl at>", <>.

    You can contact me by mail or on "" (vincent).

    Please report any bugs or feature requests to "bug-hash-normalize at", or through the web interface at
    <>. I will
    be notified, and then you'll automatically be notified of progress on
    your bug as I make changes.

    You can find documentation for this module with the perldoc command.

        perldoc Hash::Normalize

    Copyright 2017 Vincent Pit, all rights reserved.

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