use Tie::DATA;

    foreach(keys %DATA)
    {
        print "$_ = $DATA{$_}\n";
    }

    __DATA__
    
    __foo__

    yadda yadda yadda...

    __bar__

    ee-aye ee-aye oh

    __baz__
    
    woof woof

##</code><code>##

    use Tie::DATA(':xml'); # predefined format

    foreach(keys %DATA)
    {
        print "$_ = $DATA{$_}\n";
    }

    __DATA__
    
    <foo>yadda yadda yadda...</foo>
    <bar>
        ee-aye ee-aye oh
    </bar>
    <baz>
        woof woof
    </baz>

##</code><code>##

    use Tie::DATA ( 
        sub{ ... },  # parse key/values from DATA 
        sub{ ... }   # process pairs
    );

    ...

    __DATA__

    ...

##</code><code>##

    [foo]
    baz bar etc

##</code><code>##

    <foo>baz bar etc</foo>

##</code><code>##

    #define foo
    baz bar etc

##</code><code>##

    <![foo[
        baz bar etc
    ]]>

##</code><code>##

    use Tie::DATA qr(<<<<<<<<(\w*?)>>>>>>>>);

    use Tie::DATA sub{split(/\s*:SEGMENT\s+(\w+)\s*/, shift);}

    use Some::Mad::Parser;
    use Tie::DATA \&Some::Mad::Parser::parse;
    


##</code><code>##

    use Tie::DATA(':ini', 'proc_kv');

    foreach(keys %DATA)
    {
        print "$_ = $DATA{$_}\n";
    }

    # our processing function, checks for 
    # and removes processing hints in our keys
    # (see __DATA__)
    sub proc_kv
    {
        my ($k, $v) = @_;

        if($k =~ /:/)
        {
            my ($tag, $hint) = split(/:/, $k);
            $k = $tag;

            if($hint eq 'nowhitespace')
            {
                $v = ...
            }
            else
            {
                $v = ...
            }
        }

        return($k,$v);
    }

    __DATA__
    
    [foo:nowhitespace]
    yadda yadda yadda...
    
    [bar]
    ee-aye ee-aye oh

    [baz]
    woof woof

##</code><code>##

    use My::Big::Routine;
    use Tie::DATA(':ini', 'My::Big::Routine::go');

    foreach(keys %DATA)
    {
        print "$_ = $DATA{$_}\n";
    }