Mixy.pm6

my role Mixy does Baggy  {

    method of() { Real }

    multi method hash(Mixy:D: --> Hash:D) { self!HASHIFY(Real) }
    multi method Hash(Mixy:D: --> Hash:D) { self!HASHIFY(Any) }

    multi method kxxv(Mixy:D:) {
        Failure.new(".kxxv is not supported on a {self.^name}")
    }

    multi method grab(Mixy:D: $count?) {
        Failure.new(".grab is not supported on a {self.^name}")
    }

    multi method pick(Mixy:D: $count?) {
        Failure.new(".pick is not supported on a {self.^name}, maybe use .roll instead?")
    }

    multi method roll(Mixy:D:) {
        nqp::if(
          (my \raw := self.RAW-HASH) && (my \total := self!total-positive),
          nqp::getattr(
            nqp::iterval(Rakudo::QuantHash.MIX-ROLL(raw,total)),Pair,'$!key'
          ),
          Nil
        )
    }
    multi method roll(Mixy:D: Whatever) {
        Seq.new(nqp::if(
          (my \raw := self.RAW-HASH) && (my \total := self!total-positive),
          Rakudo::Iterator.Callable( {
              nqp::getattr(
                nqp::iterval(Rakudo::QuantHash.MIX-ROLL(raw,total)),Pair,'$!key'
              )
          }, True ),
          Rakudo::Iterator.Empty
        ))
    }
    multi method roll(Mixy:D: Callable:D $calculate) {
      nqp::if(
        (my $total := self!total-positive),
        self.roll($calculate($total)),
        Seq.new(Rakudo::Iterator.Empty)
      )
    }
    multi method roll(Mixy:D: $count) {
        nqp::if(
          $count == Inf,
          self.roll(*),                         # let Whatever handle it
          Seq.new(nqp::if(                      # something else as count
            (my $todo = $count.Int) < 1, # also handles NaN
            Rakudo::Iterator.Empty,             # nothing to do
            nqp::if(
              (my \raw := self.RAW-HASH) && (my \total := self!total-positive)
                && ++$todo,
              Rakudo::Iterator.Callable( {      # need to do a number of times
                  nqp::if(
                    --$todo,
                    nqp::getattr(
                      nqp::iterval(Rakudo::QuantHash.MIX-ROLL(raw,total)),
                      Pair,
                      '$!key'
                    ),
                    IterationEnd
                  )
              }),
              Rakudo::Iterator.Empty            # nothing to roll for
            )
          ))
        )
    }

#--- object creation methods
    method new-from-pairs(Mixy:_: *@pairs --> Mixy:D) {
        nqp::if(
          (my \iterator := @pairs.iterator).is-lazy,
          Failure.new(X::Cannot::Lazy.new(:action<coerce>,:what(self.^name))),
          nqp::create(self).SET-SELF(
            Rakudo::QuantHash.ADD-PAIRS-TO-MIX(
              nqp::create(Rakudo::Internals::IterationSet),iterator,self.keyof
            )
          )
        )
    }

#--- coercion methods
   sub SETIFY(\mixy, \type) {
        nqp::if(
          (my \raw := mixy.RAW-HASH) && nqp::elems(raw),
          nqp::stmts(
            (my \elems := nqp::clone(raw)),
            (my \iter := nqp::iterator(elems)),
            nqp::while(
              iter,
              nqp::if(
                nqp::getattr(nqp::iterval(nqp::shift(iter)),Pair,'$!value') < 0,
                nqp::deletekey(elems,nqp::iterkey_s(iter)),
                nqp::bindkey(
                  elems,
                  nqp::iterkey_s(iter),
                  nqp::getattr(nqp::iterval(iter),Pair,'$!key')
                )
              )
            ),
            nqp::create(type).SET-SELF(elems)
          ),
          nqp::if(
            nqp::eqaddr(type,Set),
            set(),
            nqp::create(type)
          )
        )
    }
    multi method Set(Mixy:D:)     { SETIFY(self,Set)     }
    multi method SetHash(Mixy:D:) { SETIFY(self,SetHash) }

    sub BAGGIFY(\mixy, \type) {
        nqp::if(
          (my \raw := mixy.RAW-HASH) && nqp::elems(raw),
          nqp::stmts(                               # something to coerce
            (my \elems := nqp::clone(raw)),
            (my \iter := nqp::iterator(elems)),
            nqp::while(
              iter,
              nqp::if(
                (my \value := nqp::getattr(
                  nqp::iterval(nqp::shift(iter)),Pair,'$!value'
                ).Int) > 0,                         # .Int also deconts
                nqp::bindkey(                       # ok to keep value.Int
                  elems,
                  nqp::iterkey_s(iter),
                  nqp::p6bindattrinvres(
                    nqp::iterval(iter),Pair,'$!value',value)
                ),
                nqp::deletekey(elems,nqp::iterkey_s(iter))
              )
            ),
            nqp::create(type).SET-SELF(elems),
          ),
          nqp::if(                                  # nothing to coerce
            nqp::istype(type,Bag),
            bag(),
            nqp::create(BagHash)
          )
        )
    }

    multi method Bag(Baggy:D:)     { BAGGIFY(self, Bag)     }
    multi method BagHash(Baggy:D:) { BAGGIFY(self, BagHash) }
}

# vim: ft=perl6 expandtab sw=4