[Raku] ISBN Verifier

isbn-verifier.raku

grammar ISBN {

    token TOP        {  <tenner>  |  <niner-xray>  }

    token tenner     { [ <digit> <:Pd> ? ] ** 10   }
    token niner-xray { [ <digit> <:Pd> ? ] **  9 X }

}

class ISBN::Verify {

    method TOP ( $/ ) {
        make sum( $_ Z× ( 10...1 ) ) %% 11 with flat
        $<tenner><digit> // $<niner-xray><digit>, 10
    }

}

sub is-isbn10 ( $barcode ) is export {

    ISBN.parse( $barcode, actions => ISBN::Verify )
        .made
      // False

}