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Update based on Kerrick's latest changes

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@ -1,5 +1,5 @@
PEP: 394
Title: The "python" command on Unix-Like Systems
Title: The "python" Command on Unix-Like Systems
Version: $Revision$
Last-Modified: $Date$
Author: Kerrick Staley <mail@kerrickstaley.com>,
@ -8,7 +8,7 @@ Status: Draft
Type: Informational
Content-Type: text/x-rst
Created: 02-Mar-2011
Post-History: 04-Mar-2011
Post-History: 04-Mar-2011, 20-Jul-2011
Abstract
@ -40,6 +40,11 @@ Recommendation
* For the time being, it is recommended that ``python`` should refer to
``python2`` (however, some distributions have already chosen otherwise; see
Notes below).
* The Python 2.x ``idle``, ``pydoc``, and ``python-config`` commands should
likewise be available as ``idle2``, ``pydoc2``, and ``python2-config``,
with the original commands invoking these versions by default, but possibly
invoking the Python 3.x versions instead if configured to do so by the
system administrator.
* In order to tolerate differences across platforms, all new code that needs
to invoke the Python interpreter should not specify ``python``, but rather
should specify either ``python2`` or ``python3`` (or the more specific
@ -55,9 +60,9 @@ Recommendation
interpreter location remains the preferred approach.
These recommendations are the outcome of the relevant python-dev discussion in
March 2011 [1] (NOTE: More accurately, they will be such once that "Draft"
status disappears from the PEP header, it has been moved into the "Other
Informational PEP" section in PEP 0 and this note has been deleted)
March and July 2011 [1][2] (NOTE: More accurately, they will be such once the
"Draft" status disappears from the PEP header, it has been moved into the
"Other Informational PEP" section in PEP 0 and this note has been deleted)
Rationale
@ -142,13 +147,25 @@ Python 3 interpreter.
Application to the CPython Reference Interpreter
================================================
While technically a new feature, the ``make install`` command and the Mac OS
X installer in the 2.7 version of CPython will be adjusted to create the
new ``python2`` command in addition to the existing ``python`` and
``python2.7`` commands. This feature will first appear in CPython 2.7.2.
While technically a new feature, the ``make install`` command in the 2.7
version of CPython will be adjusted to create the ``python2.7``, ``idle2.7``,
``pydoc2.7``, and ``python2.7-config`` binaries, with ``python2``, ``idle2``,
``pydoc2``, and ``python2-config`` as hard links to the respective binaries,
and ``python``, ``idle``, ``pydoc``, and ``python-config`` as symbolic links
to the respective hard links. This feature will first appear in CPython
2.7.3.
The ``make install`` command in the CPython 3.x series will continue to
install only the ``python3`` symlink for the foreseeable future.
The ``make install`` command in the CPython 3.x series will similarly install
the ``python3.x``, ``idle3.x``, ``pydoc3.x``, and ``python3.x-config``
binaries (with appropriate ``x``), and ``python3``, ``idle3``, ``pydoc3``,
and ``python3-config`` as hard links. This feature will first appear in
CPython 3.3.
Similar adjustments will be made to the Mac OS X binary installer.
As implementation of these features in the default installers does not alter
the recommendations in this PEP, the implementation progress is managed on the
tracker as issue <TBD>.
Impact on PYTHON* Environment Variables
@ -163,28 +180,13 @@ tolerant of the presence of multiple versions of Python on a system than the
direct use of ``PYTHONPATH``.
Exclusions of MS Windows
========================
Exclusion of MS Windows
=======================
This PEP deliberately excludes any proposals relating to Microsoft Windows.
The use of parallel installs on Windows suffers from numerous issues,
including the "last installed wins" behaviour for handling of file
associations, a lack of universal robust symlink support for easy aliasing of
commands, the fact that the Python executable is not available on ``PATH`` by
default, the fact that the ``python.exe`` and ``pythonw.exe`` names are
used for both Python 2 and Python 3 binaries and the lack of distinction
between the different Python versions when the Start menu shortcuts are
divorced from their containing folders (e.g. when they appear in the
"Recently Used" list.
While these questions are well worth addressing, they do not have easy
answers. The authors of this particular PEP aren't inclined to even begin
trying to answer them, but anyone that wants to tackle them should feel free
to start working on their own PEP.
Note that, while the topic has been excluded from this PEP, there is plenty of
material in the linked python-dev discussion that may be useful in the design
and implementation of a Windows-specific solution.
This PEP deliberately excludes any proposals relating to Microsoft Windows, as
devising an equivalent solution for Windows was deemed too complex to handle
here. PEP 397 and the related discussion on the python-dev mailing list
address this issue.
References
@ -193,6 +195,9 @@ References
[1] Support the /usr/bin/python2 symlink upstream (with bonus grammar class!)
(http://mail.python.org/pipermail/python-dev/2011-March/108491.html)
[2] Rebooting PEP 394 (aka Support the /usr/bin/python2 symlink upstream)
(http://mail.python.org/pipermail/python-dev/2011-July/112322.html)
Copyright
===========