Sample 1-way LinkedList in Python as well as a way to make a copy that is reversed

linked_liat.py

#!/data/data/com.termux/files/usr/bin/python3
# vim: fileencoding=utf8:filetype=python:syntax=python:nu:ts=2:shiftwidth=2:softtabstop=2:expandtab


#    linked_list.py  sample program and reversal strategy w/ custom class
#    Copyright (C) 2020  ~Katie Heart
#
#    This program is free software: you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation, either version 3 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program.  If not, see <https://www.gnu.org/licenses/>.

class Link1Way:

  def __init__ (self, value, nextLink=None, /):
    self.value = value
    self._nextLink = None
    if nextLink is not None:
      self.nextLink = nextLink

  @property
  def value (self, /):
    return self._value

  @value.setter
  def value (self, x, /):
    self._value = x

  def hasNext (self, /):
    return self._nextLink is not None

  @property
  def nextLink (self, /):
    if self._nextLink is None:
      raise AttributeError() #FIXME
    return self._nextLink

  @nextLink.setter
  def nextLink (self, x, /):
    if not isinstance(x, Link1Way):
      raise TypeError() #FIXME
    self._nextLink = x

  @nextLink.deleter
  def nextLink (self, /):
    if self._nextLink is None:
      raise AttributeError() #FIXME
    self._nextLink = None



KIND_NORMAL = 0
KIND_LINKS = 1
KIND_LINKED_LIST = 2

class LinkedList1Way:
  
  def __init__ (self, itr=None, /, kind=KIND_NORMAL):
    self._firstLink = None
    if itr is None:
      return
    if kind not in (KIND_NORMAL, KIND_LINKS, KIND_LINKED_LIST):
      raise ValueError() #FIXME
    method = kind == KIND_NORMAL
    prev = None
    for i in itr:
      # convert / validate
      if method:
        i = Link1Way(i)
      elif not isinstance(i, Link1Way):
        raise TypeError() #FIXME
      else:
        i = Link1Way(i.value)
      #  do action
      if prev is None:
        self.firstLink = i
      else:
        prev.nextLink = i
      prev = i

  def __iter__ (self, /):
    return self.iterLinks()

  def iterLinks (self, /):
    if not self.hasContent():
      return
    i = self.firstLink
    yield i
    while  i.hasNext():
      i = i.nextLink
      yield i

  def iterValues (self, /):
    for i in self.iterLinks():
      yield i.value

  def hasContent (self, /):
    return self._firstLink is not None

  @property
  def firstLink (self, /):
    if self._firstLink is None:
      raise AttributeError() #FIXME
    return self._firstLink

  @firstLink.setter
  def firstLink (self, x, /):
    if not isinstance(x, Link1Way):
      raise TypeError() #FIXME
    self._firstLink = x

  @firstLink.deleter
  def firstLink (self, /):
    if self._firstLink is None:
      raise AttributeError() #FIXME
    self._firstLink = None



#----------

def _output (data, prefix, /):
  print(end='{!s}['.format(prefix))
  prefix = ''
  for i in data:
    print(end='{!s} {!r}'.format(prefix, i))
    if not prefix:
      prefix = ','
  print(' ]' if prefix else ']')


def _main ():
  # generate
  one = tuple( (i + i ** 2) for i in range(10) )
  _output(one, 'Source: ')
  # make it a linked list (visually verify it is the same)
  two = LinkedList1Way(one)
  _output(two.iterValues(), 'Verifying LinkedList1Way: ')
  # make a reversed one.
  three = LinkedList1Way()
  for i in two.iterLinks(): # __iter__ uses this but we'll be explicit
    i = Link1Way(i.value)
    if three.hasContent():
      i.nextLink = three.firstLink
    three.firstLink = i
  # finally ...  output the results
  _output(three.iterValues(), 'Reversed: ')

if __name__ == '__main__':
  _main()