|  | Inquiry regarding the name of subprocess.Popen class | | |
| | | Jeremy Banks |  |
|  Posted: Mon Sep 01, 2008 5:23 am Post subject: Inquiry regarding the name of subprocess.Popen class |  |
Hi. I wondered if anyone knew the rationale behind the naming of the
Popen class in the subprocess module. Popen sounds like the a suitable
name for a function that created a subprocess, but the object itself is
a subprocess, not a "popen". It seems that it would be more accurate to
just name the class Subprocess, can anyone explain why this is not the
case?
Thank you. |
| |
| | | Gabriel Genellina | |
| | Posted: Tue Sep 02, 2008 6:36 am Post subject: Re: Inquiry regarding the name of subprocess.Popen class | |
En Mon, 01 Sep 2008 04:23:38 -0300, Jeremy Banks <jeremy@jeremybanks.ca> escribió:
| Quote: | Hi. I wondered if anyone knew the rationale behind the naming of the
Popen class in the subprocess module. Popen sounds like the a suitable
name for a function that created a subprocess, but the object itself is
a subprocess, not a "popen". It seems that it would be more accurate to
just name the class Subprocess, can anyone explain why this is not the
case?
|
I have no idea - but I agree, Subprocess would have been a better name.
--
Gabriel Genellina |
| |
| | | Gabriel Genellina | |
| | Posted: Tue Sep 02, 2008 6:36 am Post subject: Re: Inquiry regarding the name of subprocess.Popen class | |
En Mon, 01 Sep 2008 04:23:38 -0300, Jeremy Banks <jeremy@jeremybanks.ca> escribió:
| Quote: | Hi. I wondered if anyone knew the rationale behind the naming of the
Popen class in the subprocess module. Popen sounds like the a suitable
name for a function that created a subprocess, but the object itself is
a subprocess, not a "popen". It seems that it would be more accurate to
just name the class Subprocess, can anyone explain why this is not the
case?
|
I have no idea - but I agree, Subprocess would have been a better name.
--
Gabriel Genellina |
| |
| | | Marc 'BlackJack' Rintsch | |
| | Posted: Tue Sep 02, 2008 10:27 am Post subject: Re: Inquiry regarding the name of subprocess.Popen class | |
On Tue, 02 Sep 2008 05:02:07 -0700, Nicola Musatti wrote:
| Quote: | On Sep 1, 9:23 am, Jeremy Banks <jer...@jeremybanks.ca> wrote:
Hi. I wondered if anyone knew the rationale behind the naming of the
Popen class in the subprocess module. Popen sounds like the a suitable
name for a function that created a subprocess, but the object itself is
a subprocess, not a "popen". It seems that it would be more accurate to
just name the class Subprocess, can anyone explain why this is not the
case?
The Python class is a generalization of the standard Posix function of
(almost) the same name:
LINK
|
So it's a name of a *function* and it's a little bit unsuitable for a
*class*. As Jeremy wrote: the instances represent *processes* not
"popen"s, whatever that may be.
Ciao,
Marc 'BlackJack' Rintsch |
| |
| | | Derek Martin | |
| | Posted: Tue Sep 02, 2008 11:28 am Post subject: Re: Inquiry regarding the name of subprocess.Popen class | |
On Tue, Sep 02, 2008 at 12:27:49PM +0000, Marc 'BlackJack' Rintsch wrote:
| Quote: | The Python class is a generalization of the standard Posix function of
(almost) the same name:
LINK
So it's a name of a *function* and it's a little bit unsuitable for a
*class*. As Jeremy wrote: the instances represent *processes* not
"popen"s, whatever that may be.
|
I would argue that they don't represent processes at all; the object
is a set of files which connect the standard I/O streams of a
subprocess to its parent, and methods to operate on those files. The
C library's popen() function, on which this class is based, provides a
means to open a file and connect it to the standard steams of a
subprocess, making it more closely analogous to what the Popen class
does/provides. As such, "Popen" is a better name to describe this
object than "subprocess" would be.
--
Derek D. Martin
LINK
GPG Key ID: 0x81CFE75D |
| |
| | | Marc 'BlackJack' Rintsch | |
| | Posted: Tue Sep 02, 2008 11:57 am Post subject: Re: Inquiry regarding the name of subprocess.Popen class | |
| |  | |
On Tue, 02 Sep 2008 09:28:42 -0400, Derek Martin wrote:
| Quote: | On Tue, Sep 02, 2008 at 12:27:49PM +0000, Marc 'BlackJack' Rintsch
wrote:
The Python class is a generalization of the standard Posix function
of (almost) the same name:
LINK
So it's a name of a *function* and it's a little bit unsuitable for a
*class*. As Jeremy wrote: the instances represent *processes* not
"popen"s, whatever that may be.
I would argue that they don't represent processes at all; the object is
a set of files which connect the standard I/O streams of a subprocess to
its parent, and methods to operate on those files.
|
And the process' ID, an attribute with the process' return code, a method
to wait until the process is finished and file objects to communicate
with the process.
| Quote: | The C library's popen() function, on which this class is based,
provides a means to open a file and connect it to the standard steams
of a subprocess, making it more closely analogous to what the Popen
class does/provides. As such, "Popen" is a better name to describe
this object than "subprocess" would be.
|
Is strongly disagree. The class provides an interface to start and
communicate with a `Subprocess`. Instances stand for processes.
With your reasoning the `file` type should be called `open`.
Ciao,
Marc 'BlackJack' Rintsch |
| |
| | | Nicola Musatti | |
| | Posted: Tue Sep 02, 2008 12:02 pm Post subject: Re: Inquiry regarding the name of subprocess.Popen class | |
On Sep 1, 9:23 am, Jeremy Banks <jer...@jeremybanks.ca> wrote:
| Quote: | Hi. I wondered if anyone knew the rationale behind the naming of the
Popen class in the subprocess module. Popen sounds like the a suitable
name for a function that created a subprocess, but the object itself is
a subprocess, not a "popen". It seems that it would be more accurate to
just name the class Subprocess, can anyone explain why this is not the
case?
|
The Python class is a generalization of the standard Posix function of
(almost) the same name: LINK
Cheers,
Nicola Musatti |
| |
| | | Derek Martin | |
| | Posted: Tue Sep 02, 2008 1:39 pm Post subject: Re: Inquiry regarding the name of subprocess.Popen class | |
| | | |
On Tue, Sep 02, 2008 at 01:57:26PM +0000, Marc 'BlackJack' Rintsch wrote:
| Quote: | I would argue that they don't represent processes at all; the object is
a set of files which connect the standard I/O streams of a subprocess to
its parent, and methods to operate on those files.
And the process' ID, an attribute with the process' return code, a method
to wait until the process is finished and file objects to communicate
with the process.
|
The name popen is an abbreviation of "pipe open" -- the function, and
the class, open pipes to communicate with another process. What you
said is correct; however there are numerous other ways to open
subprocesses. The focus of popen is the communication aspect -- the
opening and control of the pipes -- not the subprocess. That's the
key difference between popen() and all the other methods of starting a
subprocess.
| Quote: | The C library's popen() function, on which this class is based,
provides a means to open a file and connect it to the standard steams
of a subprocess, making it more closely analogous to what the Popen
class does/provides. As such, "Popen" is a better name to describe
this object than "subprocess" would be.
Is strongly disagree. The class provides an interface to start and
communicate with a `Subprocess`. Instances stand for processes.
|
There's more than one way to look at it. You can disagree all you
like, but your interpretation disagrees with the historical intent of
popen.
| Quote: | With your reasoning the `file` type should be called `open`.
|
In this case, the file is a pipe, and the 'p' in popen represents the
pipe. Unix, by and large, doesn't care that it's a pipe -- file I/O
is intended to work the same way regardless of whether it's a pipe, a
socket, a file on disk, a special device file, or any other file-like
object you can imagine. That's why I said "file" instead of "pipe" in
my explanation.
Note that in all of these links that talk about popen, the focus is on
opening pipes or file objects, not on subprocesses:
LINK
LINK
LINK
LINK
LINK
The Linux man page unfortunately copies (verbatim) the FreeBSD man
page, which gets it wrong. You can not open a process, but you can
definitely open a pipe.
--
Derek D. Martin
LINK
GPG Key ID: 0x81CFE75D |
| |
| | | Marc 'BlackJack' Rintsch | |
| | Posted: Tue Sep 02, 2008 4:47 pm Post subject: Re: Inquiry regarding the name of subprocess.Popen class | |
| | | |
On Tue, 02 Sep 2008 11:39:09 -0400, Derek Martin wrote:
| Quote: | On Tue, Sep 02, 2008 at 01:57:26PM +0000, Marc 'BlackJack' Rintsch
wrote:
I would argue that they don't represent processes at all; the object
is a set of files which connect the standard I/O streams of a
subprocess to its parent, and methods to operate on those files.
And the process' ID, an attribute with the process' return code, a
method to wait until the process is finished and file objects to
communicate with the process.
The name popen is an abbreviation of "pipe open" -- the function, and
the class, open pipes to communicate with another process. What you
said is correct; however there are numerous other ways to open
subprocesses. The focus of popen is the communication aspect -- the
opening and control of the pipes -- not the subprocess. That's the key
difference between popen() and all the other methods of starting a
subprocess.
|
But I'm not talking about the `popen()` function but the
`subprocess.Popen` class.
| Quote: | The C library's popen() function, on which this class is based,
provides a means to open a file and connect it to the standard steams
of a subprocess, making it more closely analogous to what the Popen
class does/provides. As such, "Popen" is a better name to describe
this object than "subprocess" would be.
Is strongly disagree. The class provides an interface to start and
communicate with a `Subprocess`. Instances stand for processes.
There's more than one way to look at it. You can disagree all you like,
but your interpretation disagrees with the historical intent of popen.
|
That's why I think the name `Popen` is not so good for it. Because it
does more than `popen()` and if it is called `Subprocess` or just
`Process` then it would be merely an implementation detail, that the
`popen()` function is called at some point. If it is at all, because
`popen()` on C level can just open a pipe in *one* direction.
| Quote: | Note that in all of these links that talk about popen, the focus is on
opening pipes or file objects, not on subprocesses:
LINK
LINK LINK
LINK
LINK
|
And all of the links talk about the `popen()` function, not about the
functionality the `Popen` class provides. Which is much more than that
simple pipe `popen()` returns.
| Quote: | The Linux man page unfortunately copies (verbatim) the FreeBSD man page,
which gets it wrong. You can not open a process, but you can definitely
open a pipe.
|
Ah, when their terminology doesn't match yours, they must get it
wrong. ;-)
Ciao,
Marc 'BlackJack' Rintsch |
| |
| | | Gabriel Genellina | |
| | Posted: Tue Sep 02, 2008 6:22 pm Post subject: Re: Inquiry regarding the name of subprocess.Popen class | |
| | | |
En Tue, 02 Sep 2008 12:39:09 -0300, Derek Martin <code@pizzashack.org> escribió:
| Quote: | On Tue, Sep 02, 2008 at 01:57:26PM +0000, Marc 'BlackJack' Rintsch wrote:
I would argue that they don't represent processes at all; the object is
a set of files which connect the standard I/O streams of a subprocess to
its parent, and methods to operate on those files.
And the process' ID, an attribute with the process' return code, a method
to wait until the process is finished and file objects to communicate
with the process.
The name popen is an abbreviation of "pipe open" -- the function, and
the class, open pipes to communicate with another process. What you
said is correct; however there are numerous other ways to open
subprocesses. The focus of popen is the communication aspect -- the
opening and control of the pipes -- not the subprocess. That's the
key difference between popen() and all the other methods of starting a
subprocess.
|
Totally irrelevant here - we are talking about the subprocess module, not the popen C function.
| Quote: | The C library's popen() function, on which this class is based,
|
No, subprocess.Popen does not use -directly or indirectly- the C popen function. It uses fork or CreateProcess in Windows.
| Quote: | Note that in all of these links that talk about popen, the focus is on
opening pipes or file objects, not on subprocesses:
LINK
LINK
LINK
LINK
LINK
|
Again, irrelevant.
| Quote: | The Linux man page unfortunately copies (verbatim) the FreeBSD man
page, which gets it wrong. You can not open a process, but you can
definitely open a pipe.
|
(Ok, if it doesn't agree with you, it must be wrong)
Classes represent "things", and class names should be nouns. Functions represent "actions", and their names should be verbs. popen is a good name for a function; Popen is a bad name for a class.
--
Gabriel Genellina |
| |
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