NAME
    bitflag::ct - = bitflag + grouping

SYNOPSIS
   Group of Flags by handle variable
    "package A1;"
            require Exporter;
            EXPPORT_OK = qw( getmask $mc1 $mc2 );
            our ($mc1,$mc2);
            use bitflag::ct {handle=>\$mc1}, qw(I1 I2 I3 ...);
            use bitflag::ct {handle=>\$mc2}, qw(J1 J2 J3 ...);

    "package C1;"
            use A1 qw(getmask $mc1 $mc2);
            $u = $mc1->getmask(qw(K3 K5 K11 ...));
            $v = $mc2->getmask(qw(L3 L8 L5 ...));

   Group of Flags by handle constant
    "package A2;"
            require Exporter;
            EXPPORT_OK = qw( getmask fgroupG fgroupH );
            use bitflag::ct { handle => 'fgroupG' }, qw(I1 I2 I3 ...);
            use bitflag::ct { handle => 'fgroupH' }, qw(J1 J2 J3 ...);

    "package C2;"
            use A2 qw( getmask fgroupG fgroupH );
            $u = fgroupG->getmask(qw(K3 K5 K11 ...));
            $v = fgroupH->getmask(qw(L3 L8 L5 ...));

   Group associated to module name
    "package A3; "
            use bitflag::ct qw(K1 K2 ...);

        Series of constants "K1,K2,K3 ..." now available with values
        "1,2,4,.."

            do  something with constants K1, K3|~K4 and the like
            sub f
            {
                $v = getmask A @_
                ...
            }

    "package B3; "
            use bitflag::ct qw(L1 L2 ...);

            sub g
            {
                $w = getmask B @_
                ...
            }

    "package C3;"
            use A3;
            use B3;
            A3::f(qw(K3 K5 K11 ...));    # sample choices
            B3::g(qw(L3 L8 L5 ...));

        Inside "A3::f" from "$v=getmask A3 @_" the arguments arrive as
        "K3|K5|K11", Likewise "B3::g" from "$w=getmask B3 @_" as "L3|L8|L5".

DESCRIPTION
    Have a look at pragma 'bitflag' before reading this. If just one group
    of names for different bitflag are considered in an application then
    module 'bitflag' is the slim solution. Only if different groups of
    bitflag need either distinct namespaces or individual options this
    class is the right solution.

    When necessity arise to upgrade from using 'bitflag' to 'bitflag::ct'
    this can easily be done: If a second group will be required in the same
    package, handles must be introduced, one for each group. This handle can
    be referred to either by a variable or a constant. Code-snippets before
    upgrade look like

        package A;
        use bitflag qw(V1 V2 ...);         (1)     define in package A

        package C;
        A:getmask qw(...);                  (2)     call from package C

    upgrading replaces above code lines (1),(2) by

        use bitflag::ct {handle=>\$vhandle} qw(V1 V2 ...); (1)
        $vhandle->getmask qw(...);                          (2)

    or by

        use bitflag::ct {handle=>'hc'} qw(V1 V2 ...);      (1)
        hc->getmask qw(...);                                (2)

    If the second group is located in another package, say "B", the clause
    "use bitflag::ct" can be applied without 'handle' in which case the
    package names "A, B" shall replace the handle object in front of its
    method "getmask". Doing so, a default handle is automatically created
    for the surrounding package. When expression "A->gethandle(...)" gets
    evaluated by the interpreter, the token "A" first will be substituted by
    the default handle provided in package "A".

OPTIONS
    As with bitflag a hash may be given as first argument in order to
    specify options. Option names "sm" and "ic" are described in manpage
    bitflag, the new option "handle" was presented now. A further new
    option is

        alias => \&reducer

    Similar to 'ic' this allow using alias definitions of the flagnames when
    used as arguments of "getmask". That is, if a bitflag name, say
    'CHECK_X', is introduced with

        use bitflag::ct ... CHECK_X ...

    a string $cx is accepted as "CHECK_X", if
    "reducer($cx)=reducer('CHECK_X')". The string representation of the
    builtin functions "uc,lc,ucfirst" can be used as reducers in place of
    "sub {uc $_[0]}, ...".

AUTHOR
    Josef Schönbrunner <j.schoenbrunner@schule.at>

COPYRIGHT AND LICENSE
    Copyright (c) 2008 by Josef Schönbrunner This library is free software;
    you can redistribute it and/or modify it under the same terms as Perl
    itself, either Perl version 5.8.7 or, at your option, any later version
    of Perl 5 you may have available.