CPAN::Groonga

_json = sub { my $id = shift; ...; return $json; };
    my $get_xml  = sub { my $id = shift; ...; return $xml; };
    my $get_txt  = sub { my $id = shift; ...; return $txt; };

    unAPI
        json 

=> wrAPI( $get_json => 'application/json' ),
        xml  => wrAPI( $get_xml  => 'application/xml' ),
        txt  => wrAPI( $get_txt  => 'text/plain', docs => 'http://example.com' );

The function C<

s resource in JSON
    my $app2 = sub { ... };   # PSGI app that serves resource in XML
    my $app3 = sub { ... };   # PSGI app that serves resource in plain text

    unAPI
        json => [ $app1 =