my $config = config(
    bool   => true,
    token => 'a single string',
    value => [ 'a', 'list', 'of', 'strings' ],
    blah   => store(   # This function leaves a "constructor" in the config, that generates a new object when traversed.
        key => val, ...  # Object typed and configured by these arguments...
    ),
    ...
);
...
my $object = Type->new($config);  # As Type builds an object, it references $config->value(), $config->token()...
...
my $widget = $config->{path/to/some/nested/doohickey};  # This is actually a nested tree traversal underneath...
my $thingy = $widget->evaluate($with_this_context);

##</code><code>##

sub FETCH {
    my $self = shift;
    if (! @_) {
        return $self->[0]->{FETCH};
    }
    ...
}

##</code><code>##

$config->{FETCH} = SomeWidget->new(...);
my $response = $config->FETCH->(
    term => [ 'range', 'of', 'values' ], ...
);

##</code><code>##

sub FIRSTKEY {
    my $self = shift;
    if (! @_) {
        return $self->[0]->{FIRSTKEY};
    }
    # ... walk the tree to gather nested keys
    $self->[1]->{iter} = \@list;
    # $_[0] is an empty array provided by the machinery that calls ->FIRSTKEY underneath.
    my $name = shift(@list);
    push(@{$_[0]}, $name); # Either way works...
    return $name;
}

##</code><code>##

# XXX: When dereferencing config keys, don't say ->FIRSTKEY, ->DESTROY, ...