Io Parrot again

gistfile1.txt

#IoObject method(args)
#  $1 = VTABLE(IoObject).get(IoObject, "method")
#  $2 = VTABLE(IoObject).get($1, "isActivable", "0")
#  $3 = $1 0#perform(args) [if $2]
#    VTABLE(IoObject).call($1, "perform", args)
#  $3 = $2                 [otherwise]

IoObject view#method(args)
  $1 = VTABLE(IoObject).get(IoObject, "method", "view")
  return VTABLE($1).call($1, IoObject, args)
  [$1 is IoBuiltin]
    ... do the built-in work ...
  [$1 is IoObject]
    $2 = VTABLE(IoObject).get($1, "isActivable", "0")
    [if not $2]
      return $1
    [if $2]
      $3 = VTABLE(IoObject).get($1, "perform", "0")
      return VTABLE($3).call($3, $1, args)

Implementation
==============

VTABLE(IoObject).get($pmc, $slotName, $slotView)
  return the slot object or nil

VTABLE(IoObject).call($pmc, $args...)
  $1 = VTABLE(IoObject).get($pmc, "isActivable", "0")
  [if $1]
    $2 = VTABLE(IoObject).get($pmc, "perform", "0")
    $3 = VTABLE($2).call($2, $pmc, $args...)
  [unless $1]
    return $pmc

pmclass IoBuiltin is IoObject

VTABLE(IoBuiltin).call($pmc, $self, $args...)
  [builtin is 'Method perform']
    $1 = VTABLE(IoBuiltin).get($pmc, "code", ???)
    execute code $1 in context of $self
  [...]
    ...

Normal Io
=========

method(args)
  $1 = $self getSlot("method")
  $1 = $self getSlot("forward") [if not $1]
  $2 = $1 getSlot("isActivable")
  return $1                        [if not $2]
  return $1 performOn($self, args) [if $2]
    $3 = $1 getSlot("performOn")
    $4 = $3 getSlot("isActivable")
    return $3                              [if not $4]
    return $3 performOn($1, ($self, args)) [if $4]
      no recursion because performOn is a CFunction