Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > comp.lang.python > #18942
| Date | 2012-01-13 13:24 -0600 |
|---|---|
| From | Evan Driscoll <edriscoll@wisc.edu> |
| Subject | Re: copy on write |
| References | (2 earlier) <CAPTjJmr-069xisN6h4Cxt77vWbb+VhtMb-LRNfvyphwGz0C5GA@mail.gmail.com> <mailman.4714.1326462667.27778.python-list@python.org> <jephmt$hhp$1@reader1.panix.com> <mailman.4718.1326473361.27778.python-list@python.org> <9nb5ubFu17U2@mid.individual.net> |
| Newsgroups | comp.lang.python |
| Message-ID | <mailman.4728.1326486286.27778.python-list@python.org> (permalink) |
On 01/13/2012 10:54 AM, Neil Cerutti wrote:
> If you've ever implemented operator=, operator+, and operator+=
> in C++ you'll know how and why they are different.
At the same time, you'd also know that that implementing them in such a
way that 'a += b' does *not* perform the same action as 'a = a + b' is
considered very bad-mannered.
In fact, it's often suggested (e.g. in "More Effective C++"'s Item 22,
though this is not the main thrust of that section) to implement
operator+ in terms of += to ensure that this is the case:
MyType operator+ (MyType left, MyType right) {
MyType copy = left; copy += right; return copy;
}
> A C++
> programmer would be wondering how either can work on immutable
> objects, and that's where Python's magical rebinding semantics
> come into play.
IMO a C++ programmer wouldn't be likely to wonder that much at all
because he or she wouldn't view the objects as immutable to begin with.
:-) 'x = 5; x += 1;' makes perfect sense in C++, just for a somewhat
different reason.
Evan
Back to comp.lang.python | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
copy on write Eduardo Suarez-Santana <esuarez@itccanarias.org> - 2012-01-13 11:33 +0000
Re: copy on write Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-01-13 12:10 +0000
Re: copy on write Chris Angelico <rosuav@gmail.com> - 2012-01-13 23:30 +1100
Re: copy on write Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-01-13 13:04 +0000
Re: copy on write Ethan Furman <ethan@stoneleaf.us> - 2012-01-13 10:40 -0800
Re: copy on write 88888 Dihedral <dihedral88888@googlemail.com> - 2012-01-13 14:26 -0800
Re: copy on write 88888 Dihedral <dihedral88888@googlemail.com> - 2012-01-13 14:26 -0800
Re: copy on write John O'Hagan <research@johnohagan.com> - 2012-02-02 14:18 +1100
Re: copy on write Devin Jeanpierre <jeanpierreda@gmail.com> - 2012-02-02 01:34 -0500
Re: copy on write John O'Hagan <research@johnohagan.com> - 2012-02-02 19:11 +1100
Re: copy on write Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-02-02 09:16 +0000
Re: copy on write Hrvoje Niksic <hniksic@xemacs.org> - 2012-02-02 11:53 +0100
Re: copy on write MRAB <python@mrabarnett.plus.com> - 2012-02-02 16:28 +0000
Re: copy on write Devin Jeanpierre <jeanpierreda@gmail.com> - 2012-02-02 12:21 -0500
Re: copy on write John O'Hagan <research@johnohagan.com> - 2012-02-03 01:17 +1100
Re: copy on write Terry Reedy <tjreedy@udel.edu> - 2012-02-02 12:25 -0500
Re: copy on write John O'Hagan <research@johnohagan.com> - 2012-02-03 14:08 +1100
Re: copy on write Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-02-03 05:04 +0000
Re: copy on write Chris Angelico <rosuav@gmail.com> - 2012-02-03 16:28 +1100
Re: copy on write Rick Johnson <rantingrickjohnson@gmail.com> - 2012-02-03 07:35 -0800
Re: copy on write Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2012-02-03 10:08 +0100
Re: copy on write John O'Hagan <research@johnohagan.com> - 2012-02-03 21:47 +1100
Re: copy on write Wolfram Hinderer <wolfram.hinderer@googlemail.com> - 2012-02-05 06:09 -0800
Re: copy on write "OKB (not okblacke)" <brenNOSPAMbarn@NObrenSPAMbarn.net> - 2012-02-03 16:15 +0000
Re: copy on write Thomas Rachel <nutznetz-0c1b6768-bfa9-48d5-a470-7603bd3aa915@spamschutz.glglgl.de> - 2012-02-02 11:42 +0100
Re: copy on write Devin Jeanpierre <jeanpierreda@gmail.com> - 2012-01-13 08:50 -0500
Re: copy on write Grant Edwards <invalid@invalid.invalid> - 2012-01-13 15:13 +0000
Re: copy on write Devin Jeanpierre <jeanpierreda@gmail.com> - 2012-01-13 11:48 -0500
Re: copy on write Neil Cerutti <neilc@norwich.edu> - 2012-01-13 16:54 +0000
Re: copy on write Grant Edwards <invalid@invalid.invalid> - 2012-01-13 18:15 +0000
Re: copy on write Chris Angelico <rosuav@gmail.com> - 2012-01-14 05:26 +1100
Re: copy on write Grant Edwards <invalid@invalid.invalid> - 2012-01-13 19:30 +0000
Re: copy on write Neil Cerutti <neilc@norwich.edu> - 2012-01-13 20:11 +0000
Re: copy on write Evan Driscoll <edriscoll@wisc.edu> - 2012-01-13 13:24 -0600
Re: copy on write Neil Cerutti <neilc@norwich.edu> - 2012-01-13 21:20 +0000
Re: copy on write Evan Driscoll <edriscoll@wisc.edu> - 2012-01-13 16:48 -0600
Re: copy on write 88888 Dihedral <dihedral88888@googlemail.com> - 2012-02-02 05:33 -0800
Re: copy on write Evan Driscoll <edriscoll@wisc.edu> - 2012-02-02 15:20 -0600
Re: copy on write 88888 Dihedral <dihedral88888@googlemail.com> - 2012-02-02 05:33 -0800
Re: copy on write 88888 Dihedral <dihedral88888@googlemail.com> - 2012-02-03 14:16 -0800
Re: copy on write 88888 Dihedral <dihedral88888@googlemail.com> - 2012-02-03 14:16 -0800
Re: copy on write Rick Johnson <rantingrickjohnson@gmail.com> - 2012-02-01 19:51 -0800
Re: copy on write Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-02-02 05:31 +0000
csiph-web