import pixie.vm.object as object

from pixie.vm.primitives import nil

import pixie.vm.stdlib as proto

from pixie.vm.code import extend, as_var

class Cons(object.Object):

_type = object.Type(u"pixie.stdlib.Cons")

def type(self):

return Cons._type

def __init__(self, head, tail, meta=nil):

self._first = head

self._next = tail

self._meta = meta

def first(self):

return self._first

def next(self):

return self._next

def meta(self):

return self._meta

def with_meta(self, meta):

return Cons(self._first, self._next, meta)

@extend(proto._first, Cons._type)

def _first(self):

assert isinstance(self, Cons)

return self._first

@extend(proto._next, Cons._type)

def _next(self):

assert isinstance(self, Cons)

return self._next

@extend(proto._seq, Cons._type)

def _seq(self):

assert isinstance(self, Cons)

return self

@extend(proto._meta, Cons)

def _meta(self):

assert isinstance(self, Cons)

return self.meta()

@extend(proto._with_meta, Cons)

def _with_meta(self, meta):

assert isinstance(self, Cons)

return self.with_meta(meta)

@as_var("cons")

def cons(head, tail):

return Cons(head, tail)

def count(self):

cnt = 0

while self is not nil:

self = self.next()

cnt += 1

return cnt

def cons(head, tail=nil):

return Cons(head, tail, nil)