Path: eternal-september.org!news.eternal-september.org!feeder3.eternal-september.org!fu-berlin.de!uni-berlin.de!not-for-mail
From: ram@zedat.fu-berlin.de (Stefan Ram)
Newsgroups: comp.lang.python
Subject: Re: Is Lexical Binding The Norm Yet?
Date: 21 Jan 2024 07:28:12 GMT
Organization: Stefan Ram
Lines: 64
Expires: 1 Dec 2024 11:59:58 GMT
Message-ID: <prototypes-20240121082408@ram.dialup.fu-berlin.de>
References: <uo1i8c$jbru$2@dont-email.me> <86r0ijsdyj.fsf@williamsburg.bawden.org> <871qajgr9k.fsf@nightsong.com> <uo4id7$14ifr$1@dont-email.me> <jwvedeg510z.fsf-monnier+comp.lang.lisp@gnu.org> <uo9cbb$264u2$1@dont-email.me> <20240117122629.806@kylheku.com> <uo9o4k$281t4$1@dont-email.me> <qitjqi521brjnpvebd2b1bidrhevocbt62@4ax.com> <uod249$30h1g$3@dont-email.me> <prototype-20240120111210@ram.dialup.fu-berlin.de>
Mime-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
X-Trace: news.uni-berlin.de yZUfescOwqQ/D+VmzaFfnweZciYqIHmPV9HHyzbWk3n5T3
Cancel-Lock: sha1:pqlF2reCMa4v18Q7Ua7YSPUUWM0= sha256:Y2mdvl9ISDPk8hEF4G+W2lfBlmAA34KnCR5FMJZ6AoA=
X-Copyright: (C) Copyright 2024 Stefan Ram. All rights reserved.
	Distribution through any means other than regular usenet
	channels is forbidden. It is forbidden to publish this
	article in the Web, to change URIs of this article into links,
        and to transfer the body without this notice, but quotations
        of parts in other Usenet posts are allowed.
X-No-Archive: Yes
Archive: no
X-No-Archive-Readme: "X-No-Archive" is set, because this prevents some
	services to mirror the article in the web. But the article may
	be kept on a Usenet archive server with only NNTP access.
X-No-Html: yes
Content-Language: en-US
Accept-Language: de-DE-1901, en-US, it, fr-FR

Newsgroups: comp.lang.python

ram@zedat.fu-berlin.de (Stefan Ram) writes:
>from types import *

  What do you mean, the cloning part is missing?

import types

# create a new object
def counter_object(): pass

# attach a numeric field to the object
counter_object.counter_value = 0

# define a named function
def increment_value( self ): self.counter_value += 1

# attach the named function to the object as a method
counter_object.increment_value = \
types.MethodType( increment_value, counter_object )

# call the method
counter_object.increment_value()

# attach an unnamed function to the object
counter_object.get_value = \
types.MethodType( lambda self: self.counter_value, counter_object )

# call that method
# Prints "1".
print( counter_object.get_value() )

# An ad-hoc function to clone an object for the purpose of "prototype
# inheritance". Might need to be refined for more general uses.
def clone_object( object_ ):
    def new_object(): pass
    for attribute in dir( object_ ):
        if attribute[ :2 ]!= '__':
            if type( getattr( object_, attribute ))== types.MethodType:
                method = getattr( object_, attribute )
                function = types.FunctionType( method.__code__, {} )
                method = types.MethodType( function, new_object )
                setattr( new_object, attribute, method )
            else:
                field = getattr( object_, attribute )
                setattr( new_object, attribute, field )
    return new_object

# create two "clones" ("clone objects")
clone = clone_object( counter_object )
other = clone_object( counter_object )

# The clones "inherited" the counter field including its value.
# Prints "1 1 1".
print( counter_object.get_value(), clone.get_value(), other.get_value() )

# Each object's counter has a value independent from the other object's
# counter.
other.increment_value()

# Prints "1 1 2"
print( counter_object.get_value(), clone.get_value(), other.get_value() )