It has been a while since I posted a copy of PEP 1 to the mailing
lists and newsgroups. I've recently done some updating of a few
sections, so in the interest of gaining wider community participation
in the Python development process, I'm posting the latest revision of
PEP 1 here. A version of the PEP is always available on-line at
http://www.python.org/peps/pep-0001.html
Enjoy,
-Barry
-------------------- snip snip --------------------
PEP: 1
Title: PEP Purpose and Guidelines
Version: $Revision: 1.36 $
Last-Modified: $Date: 2002/07/29 18:34:59 $
Author: Barry A. Warsaw, Jeremy Hylton
Status: Active
Type: Informational
Created: 13-Jun-2000
Post-History: 21-Mar-2001, 29-Jul-2002
What is a PEP?
PEP stands for Python Enhancement Proposal. A PEP is a design
document providing information to the Python community, or
describing a new feature for Python. The PEP should provide a
concise technical specification of the feature and a rationale for
the feature.
We intend PEPs to be the primary mechanisms for proposing new
features, for collecting community input on an issue, and for
documenting the design decisions that have gone into Python. The
PEP author is responsible for building consensus within the
community and documenting dissenting opinions.
Because the PEPs are maintained as plain text files under CVS
control, their revision history is the historical record of the
feature proposal[1].
Kinds of PEPs
There are two kinds of PEPs. A standards track PEP describes a
new feature or implementation for Python. An informational PEP
describes a Python design issue, or provides general guidelines or
information to the Python community, but does not propose a new
feature. Informational PEPs do not necessarily represent a Python
community consensus or recommendation, so users and implementors
are free to ignore informational PEPs or follow their advice.
PEP Work Flow
The PEP editor, Barry Warsaw <peps(a)python.org>, assigns numbers
for each PEP and changes its status.
The PEP process begins with a new idea for Python. It is highly
recommended that a single PEP contain a single key proposal or new
idea. The more focussed the PEP, the more successfully it tends
to be. The PEP editor reserves the right to reject PEP proposals
if they appear too unfocussed or too broad. If in doubt, split
your PEP into several well-focussed ones.
Each PEP must have a champion -- someone who writes the PEP using
the style and format described below, shepherds the discussions in
the appropriate forums, and attempts to build community consensus
around the idea. The PEP champion (a.k.a. Author) should first
attempt to ascertain whether the idea is PEP-able. Small
enhancements or patches often don't need a PEP and can be injected
into the Python development work flow with a patch submission to
the SourceForge patch manager[2] or feature request tracker[3].
The PEP champion then emails the PEP editor <peps(a)python.org> with
a proposed title and a rough, but fleshed out, draft of the PEP.
This draft must be written in PEP style as described below.
If the PEP editor approves, he will assign the PEP a number, label
it as standards track or informational, give it status 'draft',
and create and check-in the initial draft of the PEP. The PEP
editor will not unreasonably deny a PEP. Reasons for denying PEP
status include duplication of effort, being technically unsound,
not providing proper motivation or addressing backwards
compatibility, or not in keeping with the Python philosophy. The
BDFL (Benevolent Dictator for Life, Guido van Rossum) can be
consulted during the approval phase, and is the final arbitrator
of the draft's PEP-ability.
If a pre-PEP is rejected, the author may elect to take the pre-PEP
to the comp.lang.python newsgroup (a.k.a. python-list(a)python.org
mailing list) to help flesh it out, gain feedback and consensus
from the community at large, and improve the PEP for
re-submission.
The author of the PEP is then responsible for posting the PEP to
the community forums, and marshaling community support for it. As
updates are necessary, the PEP author can check in new versions if
they have CVS commit permissions, or can email new PEP versions to
the PEP editor for committing.
Standards track PEPs consists of two parts, a design document and
a reference implementation. The PEP should be reviewed and
accepted before a reference implementation is begun, unless a
reference implementation will aid people in studying the PEP.
Standards Track PEPs must include an implementation - in the form
of code, patch, or URL to same - before it can be considered
Final.
PEP authors are responsible for collecting community feedback on a
PEP before submitting it for review. A PEP that has not been
discussed on python-list(a)python.org and/or python-dev(a)python.org
will not be accepted. However, wherever possible, long open-ended
discussions on public mailing lists should be avoided. Strategies
to keep the discussions efficient include, setting up a separate
SIG mailing list for the topic, having the PEP author accept
private comments in the early design phases, etc. PEP authors
should use their discretion here.
Once the authors have completed a PEP, they must inform the PEP
editor that it is ready for review. PEPs are reviewed by the BDFL
and his chosen consultants, who may accept or reject a PEP or send
it back to the author(s) for revision.
Once a PEP has been accepted, the reference implementation must be
completed. When the reference implementation is complete and
accepted by the BDFL, the status will be changed to `Final.'
A PEP can also be assigned status `Deferred.' The PEP author or
editor can assign the PEP this status when no progress is being
made on the PEP. Once a PEP is deferred, the PEP editor can
re-assign it to draft status.
A PEP can also be `Rejected'. Perhaps after all is said and done
it was not a good idea. It is still important to have a record of
this fact.
PEPs can also be replaced by a different PEP, rendering the
original obsolete. This is intended for Informational PEPs, where
version 2 of an API can replace version 1.
PEP work flow is as follows:
Draft -> Accepted -> Final -> Replaced
^
+----> Rejected
v
Deferred
Some informational PEPs may also have a status of `Active' if they
are never meant to be completed. E.g. PEP 1.
What belongs in a successful PEP?
Each PEP should have the following parts:
1. Preamble -- RFC822 style headers containing meta-data about the
PEP, including the PEP number, a short descriptive title
(limited to a maximum of 44 characters), the names, and
optionally the contact info for each author, etc.
2. Abstract -- a short (~200 word) description of the technical
issue being addressed.
3. Copyright/public domain -- Each PEP must either be explicitly
labelled as placed in the public domain (see this PEP as an
example) or licensed under the Open Publication License[4].
4. Specification -- The technical specification should describe
the syntax and semantics of any new language feature. The
specification should be detailed enough to allow competing,
interoperable implementations for any of the current Python
platforms (CPython, JPython, Python .NET).
5. Motivation -- The motivation is critical for PEPs that want to
change the Python language. It should clearly explain why the
existing language specification is inadequate to address the
problem that the PEP solves. PEP submissions without
sufficient motivation may be rejected outright.
6. Rationale -- The rationale fleshes out the specification by
describing what motivated the design and why particular design
decisions were made. It should describe alternate designs that
were considered and related work, e.g. how the feature is
supported in other languages.
The rationale should provide evidence of consensus within the
community and discuss important objections or concerns raised
during discussion.
7. Backwards Compatibility -- All PEPs that introduce backwards
incompatibilities must include a section describing these
incompatibilities and their severity. The PEP must explain how
the author proposes to deal with these incompatibilities. PEP
submissions without a sufficient backwards compatibility
treatise may be rejected outright.
8. Reference Implementation -- The reference implementation must
be completed before any PEP is given status 'Final,' but it
need not be completed before the PEP is accepted. It is better
to finish the specification and rationale first and reach
consensus on it before writing code.
The final implementation must include test code and
documentation appropriate for either the Python language
reference or the standard library reference.
PEP Template
PEPs are written in plain ASCII text, and should adhere to a
rigid style. There is a Python script that parses this style and
converts the plain text PEP to HTML for viewing on the web[5].
PEP 9 contains a boilerplate[7] template you can use to get
started writing your PEP.
Each PEP must begin with an RFC822 style header preamble. The
headers must appear in the following order. Headers marked with
`*' are optional and are described below. All other headers are
required.
PEP: <pep number>
Title: <pep title>
Version: <cvs version string>
Last-Modified: <cvs date string>
Author: <list of authors' real names and optionally, email addrs>
* Discussions-To: <email address>
Status: <Draft | Active | Accepted | Deferred | Final | Replaced>
Type: <Informational | Standards Track>
* Requires: <pep numbers>
Created: <date created on, in dd-mmm-yyyy format>
* Python-Version: <version number>
Post-History: <dates of postings to python-list and python-dev>
* Replaces: <pep number>
* Replaced-By: <pep number>
The Author: header lists the names and optionally, the email
addresses of all the authors/owners of the PEP. The format of the
author entry should be
address(a)dom.ain (Random J. User)
if the email address is included, and just
Random J. User
if the address is not given. If there are multiple authors, each
should be on a separate line following RFC 822 continuation line
conventions. Note that personal email addresses in PEPs will be
obscured as a defense against spam harvesters.
Standards track PEPs must have a Python-Version: header which
indicates the version of Python that the feature will be released
with. Informational PEPs do not need a Python-Version: header.
While a PEP is in private discussions (usually during the initial
Draft phase), a Discussions-To: header will indicate the mailing
list or URL where the PEP is being discussed. No Discussions-To:
header is necessary if the PEP is being discussed privately with
the author, or on the python-list or python-dev email mailing
lists. Note that email addresses in the Discussions-To: header
will not be obscured.
Created: records the date that the PEP was assigned a number,
while Post-History: is used to record the dates of when new
versions of the PEP are posted to python-list and/or python-dev.
Both headers should be in dd-mmm-yyyy format, e.g. 14-Aug-2001.
PEPs may have a Requires: header, indicating the PEP numbers that
this PEP depends on.
PEPs may also have a Replaced-By: header indicating that a PEP has
been rendered obsolete by a later document; the value is the
number of the PEP that replaces the current document. The newer
PEP must have a Replaces: header containing the number of the PEP
that it rendered obsolete.
PEP Formatting Requirements
PEP headings must begin in column zero and the initial letter of
each word must be capitalized as in book titles. Acronyms should
be in all capitals. The body of each section must be indented 4
spaces. Code samples inside body sections should be indented a
further 4 spaces, and other indentation can be used as required to
make the text readable. You must use two blank lines between the
last line of a section's body and the next section heading.
You must adhere to the Emacs convention of adding two spaces at
the end of every sentence. You should fill your paragraphs to
column 70, but under no circumstances should your lines extend
past column 79. If your code samples spill over column 79, you
should rewrite them.
Tab characters must never appear in the document at all. A PEP
should include the standard Emacs stanza included by example at
the bottom of this PEP.
A PEP must contain a Copyright section, and it is strongly
recommended to put the PEP in the public domain.
When referencing an external web page in the body of a PEP, you
should include the title of the page in the text, with a
footnote reference to the URL. Do not include the URL in the body
text of the PEP. E.g.
Refer to the Python Language web site [1] for more details.
...
[1] http://www.python.org
When referring to another PEP, include the PEP number in the body
text, such as "PEP 1". The title may optionally appear. Add a
footnote reference that includes the PEP's title and author. It
may optionally include the explicit URL on a separate line, but
only in the References section. Note that the pep2html.py script
will calculate URLs automatically, e.g.:
...
Refer to PEP 1 [7] for more information about PEP style
...
References
[7] PEP 1, PEP Purpose and Guidelines, Warsaw, Hylton
http://www.python.org/peps/pep-0001.html
If you decide to provide an explicit URL for a PEP, please use
this as the URL template:
http://www.python.org/peps/pep-xxxx.html
PEP numbers in URLs must be padded with zeros from the left, so as
to be exactly 4 characters wide, however PEP numbers in text are
never padded.
Reporting PEP Bugs, or Submitting PEP Updates
How you report a bug, or submit a PEP update depends on several
factors, such as the maturity of the PEP, the preferences of the
PEP author, and the nature of your comments. For the early draft
stages of the PEP, it's probably best to send your comments and
changes directly to the PEP author. For more mature, or finished
PEPs you may want to submit corrections to the SourceForge bug
manager[6] or better yet, the SourceForge patch manager[2] so that
your changes don't get lost. If the PEP author is a SF developer,
assign the bug/patch to him, otherwise assign it to the PEP
editor.
When in doubt about where to send your changes, please check first
with the PEP author and/or PEP editor.
PEP authors who are also SF committers, can update the PEPs
themselves by using "cvs commit" to commit their changes.
Remember to also push the formatted PEP text out to the web by
doing the following:
% python pep2html.py -i NUM
where NUM is the number of the PEP you want to push out. See
% python pep2html.py --help
for details.
Transferring PEP Ownership
It occasionally becomes necessary to transfer ownership of PEPs to
a new champion. In general, we'd like to retain the original
author as a co-author of the transferred PEP, but that's really up
to the original author. A good reason to transfer ownership is
because the original author no longer has the time or interest in
updating it or following through with the PEP process, or has
fallen off the face of the 'net (i.e. is unreachable or not
responding to email). A bad reason to transfer ownership is
because you don't agree with the direction of the PEP. We try to
build consensus around a PEP, but if that's not possible, you can
always submit a competing PEP.
If you are interested assuming ownership of a PEP, send a message
asking to take over, addressed to both the original author and the
PEP editor <peps(a)python.org>. If the original author doesn't
respond to email in a timely manner, the PEP editor will make a
unilateral decision (it's not like such decisions can be
reversed. :).
References and Footnotes
[1] This historical record is available by the normal CVS commands
for retrieving older revisions. For those without direct access
to the CVS tree, you can browse the current and past PEP revisions
via the SourceForge web site at
http://cvs.sourceforge.net/cgi-bin/cvsweb.cgi/python/nondist/peps/?cvsroot=…
[2] http://sourceforge.net/tracker/?group_id=5470&atid=305470
[3] http://sourceforge.net/tracker/?atid=355470&group_id=5470&func=browse
[4] http://www.opencontent.org/openpub/
[5] The script referred to here is pep2html.py, which lives in
the same directory in the CVS tree as the PEPs themselves.
Try "pep2html.py --help" for details.
The URL for viewing PEPs on the web is
http://www.python.org/peps/
[6] http://sourceforge.net/tracker/?group_id=5470&atid=305470
[7] PEP 9, Sample PEP Template
http://www.python.org/peps/pep-0009.html
Copyright
This document has been placed in the public domain.
Local Variables:
mode: indented-text
indent-tabs-mode: nil
sentence-end-double-space: t
fill-column: 70
End:
On Wed, 10 Nov 2004, John P Speno wrote:
Hi, sorry for the delayed response.
> While using subprocess (aka popen5), I came across one potential gotcha. I've had
> exceptions ending like this:
>
> File "test.py", line 5, in test
> cmd = popen5.Popen(args, stdout=PIPE)
> File "popen5.py", line 577, in __init__
> data = os.read(errpipe_read, 1048576) # Exceptions limited to 1 MB
> OSError: [Errno 4] Interrupted system call
>
> (on Solaris 9)
>
> Would it make sense for subprocess to use a more robust read() function
> which can handle these cases, i.e. when the parent's read on the pipe
> to the child's stderr is interrupted by a system call, and returns EINTR?
> I imagine it could catch EINTR and EAGAIN and retry the failed read().
I assume you are using signals in your application? The os.read above is
not the only system call that can fail with EINTR. subprocess.py is full
of other system calls that can fail, and I suspect that many other Python
modules are as well.
I've made a patch (attached) to subprocess.py (and test_subprocess.py)
that should guard against EINTR, but I haven't committed it yet. It's
quite large.
Are Python modules supposed to handle EINTR? Why not let the C code handle
this? Or, perhaps the signal module should provide a sigaction function,
so that users can use SA_RESTART.
Index: subprocess.py
===================================================================
RCS file: /cvsroot/python/python/dist/src/Lib/subprocess.py,v
retrieving revision 1.8
diff -u -r1.8 subprocess.py
--- subprocess.py 7 Nov 2004 14:30:34 -0000 1.8
+++ subprocess.py 17 Nov 2004 19:42:30 -0000
@@ -888,6 +888,50 @@
pass
+ def _read_no_intr(self, fd, buffersize):
+ """Like os.read, but retries on EINTR"""
+ while True:
+ try:
+ return os.read(fd, buffersize)
+ except OSError, e:
+ if e.errno == errno.EINTR:
+ continue
+ else:
+ raise
+
+
+ def _read_all(self, fd, buffersize):
+ """Like os.read, but retries on EINTR, and reads until EOF"""
+ all = ""
+ while True:
+ data = self._read_no_intr(fd, buffersize)
+ all += data
+ if data == "":
+ return all
+
+
+ def _write_no_intr(self, fd, s):
+ """Like os.write, but retries on EINTR"""
+ while True:
+ try:
+ return os.write(fd, s)
+ except OSError, e:
+ if e.errno == errno.EINTR:
+ continue
+ else:
+ raise
+
+ def _waitpid_no_intr(self, pid, options):
+ """Like os.waitpid, but retries on EINTR"""
+ while True:
+ try:
+ return os.waitpid(pid, options)
+ except OSError, e:
+ if e.errno == errno.EINTR:
+ continue
+ else:
+ raise
+
def _execute_child(self, args, executable, preexec_fn, close_fds,
cwd, env, universal_newlines,
startupinfo, creationflags, shell,
@@ -963,7 +1007,7 @@
exc_value,
tb)
exc_value.child_traceback = ''.join(exc_lines)
- os.write(errpipe_write, pickle.dumps(exc_value))
+ self._write_no_intr(errpipe_write, pickle.dumps(exc_value))
# This exitcode won't be reported to applications, so it
# really doesn't matter what we return.
@@ -979,7 +1023,7 @@
os.close(errwrite)
# Wait for exec to fail or succeed; possibly raising exception
- data = os.read(errpipe_read, 1048576) # Exceptions limited to 1 MB
+ data = self._read_all(errpipe_read, 1048576) # Exceptions limited to 1 MB
os.close(errpipe_read)
if data != "":
child_exception = pickle.loads(data)
@@ -1003,7 +1047,7 @@
attribute."""
if self.returncode == None:
try:
- pid, sts = os.waitpid(self.pid, os.WNOHANG)
+ pid, sts = self._waitpid_no_intr(self.pid, os.WNOHANG)
if pid == self.pid:
self._handle_exitstatus(sts)
except os.error:
@@ -1015,7 +1059,7 @@
"""Wait for child process to terminate. Returns returncode
attribute."""
if self.returncode == None:
- pid, sts = os.waitpid(self.pid, 0)
+ pid, sts = self._waitpid_no_intr(self.pid, 0)
self._handle_exitstatus(sts)
return self.returncode
@@ -1049,27 +1093,33 @@
stderr = []
while read_set or write_set:
- rlist, wlist, xlist = select.select(read_set, write_set, [])
+ try:
+ rlist, wlist, xlist = select.select(read_set, write_set, [])
+ except select.error, e:
+ if e[0] == errno.EINTR:
+ continue
+ else:
+ raise
if self.stdin in wlist:
# When select has indicated that the file is writable,
# we can write up to PIPE_BUF bytes without risk
# blocking. POSIX defines PIPE_BUF >= 512
- bytes_written = os.write(self.stdin.fileno(), input[:512])
+ bytes_written = self._write_no_intr(self.stdin.fileno(), input[:512])
input = input[bytes_written:]
if not input:
self.stdin.close()
write_set.remove(self.stdin)
if self.stdout in rlist:
- data = os.read(self.stdout.fileno(), 1024)
+ data = self._read_no_intr(self.stdout.fileno(), 1024)
if data == "":
self.stdout.close()
read_set.remove(self.stdout)
stdout.append(data)
if self.stderr in rlist:
- data = os.read(self.stderr.fileno(), 1024)
+ data = self._read_no_intr(self.stderr.fileno(), 1024)
if data == "":
self.stderr.close()
read_set.remove(self.stderr)
Index: test/test_subprocess.py
===================================================================
RCS file: /cvsroot/python/python/dist/src/Lib/test/test_subprocess.py,v
retrieving revision 1.14
diff -u -r1.14 test_subprocess.py
--- test/test_subprocess.py 12 Nov 2004 15:51:48 -0000 1.14
+++ test/test_subprocess.py 17 Nov 2004 19:42:30 -0000
@@ -7,6 +7,7 @@
import tempfile
import time
import re
+import errno
mswindows = (sys.platform == "win32")
@@ -35,6 +36,16 @@
fname = tempfile.mktemp()
return os.open(fname, os.O_RDWR|os.O_CREAT), fname
+ def read_no_intr(self, obj):
+ while True:
+ try:
+ return obj.read()
+ except IOError, e:
+ if e.errno == errno.EINTR:
+ continue
+ else:
+ raise
+
#
# Generic tests
#
@@ -123,7 +134,7 @@
p = subprocess.Popen([sys.executable, "-c",
'import sys; sys.stdout.write("orange")'],
stdout=subprocess.PIPE)
- self.assertEqual(p.stdout.read(), "orange")
+ self.assertEqual(self.read_no_intr(p.stdout), "orange")
def test_stdout_filedes(self):
# stdout is set to open file descriptor
@@ -151,7 +162,7 @@
p = subprocess.Popen([sys.executable, "-c",
'import sys; sys.stderr.write("strawberry")'],
stderr=subprocess.PIPE)
- self.assertEqual(remove_stderr_debug_decorations(p.stderr.read()),
+ self.assertEqual(remove_stderr_debug_decorations(self.read_no_intr(p.stderr)),
"strawberry")
def test_stderr_filedes(self):
@@ -186,7 +197,7 @@
'sys.stderr.write("orange")'],
stdout=subprocess.PIPE,
stderr=subprocess.STDOUT)
- output = p.stdout.read()
+ output = self.read_no_intr(p.stdout)
stripped = remove_stderr_debug_decorations(output)
self.assertEqual(stripped, "appleorange")
@@ -220,7 +231,7 @@
stdout=subprocess.PIPE,
cwd=tmpdir)
normcase = os.path.normcase
- self.assertEqual(normcase(p.stdout.read()), normcase(tmpdir))
+ self.assertEqual(normcase(self.read_no_intr(p.stdout)), normcase(tmpdir))
def test_env(self):
newenv = os.environ.copy()
@@ -230,7 +241,7 @@
'sys.stdout.write(os.getenv("FRUIT"))'],
stdout=subprocess.PIPE,
env=newenv)
- self.assertEqual(p.stdout.read(), "orange")
+ self.assertEqual(self.read_no_intr(p.stdout), "orange")
def test_communicate(self):
p = subprocess.Popen([sys.executable, "-c",
@@ -305,7 +316,8 @@
'sys.stdout.write("\\nline6");'],
stdout=subprocess.PIPE,
universal_newlines=1)
- stdout = p.stdout.read()
+
+ stdout = self.read_no_intr(p.stdout)
if hasattr(open, 'newlines'):
# Interpreter with universal newline support
self.assertEqual(stdout,
@@ -343,7 +355,7 @@
def test_no_leaking(self):
# Make sure we leak no resources
- max_handles = 1026 # too much for most UNIX systems
+ max_handles = 10 # too much for most UNIX systems
if mswindows:
max_handles = 65 # a full test is too slow on Windows
for i in range(max_handles):
@@ -424,7 +436,7 @@
'sys.stdout.write(os.getenv("FRUIT"))'],
stdout=subprocess.PIPE,
preexec_fn=lambda: os.putenv("FRUIT", "apple"))
- self.assertEqual(p.stdout.read(), "apple")
+ self.assertEqual(self.read_no_intr(p.stdout), "apple")
def test_args_string(self):
# args is a string
@@ -457,7 +469,7 @@
p = subprocess.Popen(["echo $FRUIT"], shell=1,
stdout=subprocess.PIPE,
env=newenv)
- self.assertEqual(p.stdout.read().strip(), "apple")
+ self.assertEqual(self.read_no_intr(p.stdout).strip(), "apple")
def test_shell_string(self):
# Run command through the shell (string)
@@ -466,7 +478,7 @@
p = subprocess.Popen("echo $FRUIT", shell=1,
stdout=subprocess.PIPE,
env=newenv)
- self.assertEqual(p.stdout.read().strip(), "apple")
+ self.assertEqual(self.read_no_intr(p.stdout).strip(), "apple")
def test_call_string(self):
# call() function with string argument on UNIX
@@ -525,7 +537,7 @@
p = subprocess.Popen(["set"], shell=1,
stdout=subprocess.PIPE,
env=newenv)
- self.assertNotEqual(p.stdout.read().find("physalis"), -1)
+ self.assertNotEqual(self.read_no_intr(p.stdout).find("physalis"), -1)
def test_shell_string(self):
# Run command through the shell (string)
@@ -534,7 +546,7 @@
p = subprocess.Popen("set", shell=1,
stdout=subprocess.PIPE,
env=newenv)
- self.assertNotEqual(p.stdout.read().find("physalis"), -1)
+ self.assertNotEqual(self.read_no_intr(p.stdout).find("physalis"), -1)
def test_call_string(self):
# call() function with string argument on Windows
/Peter Åstrand <astrand(a)lysator.liu.se>
Problem:
When the code contains list comprehensions (or for that matter any other
looping construct), the only way to get quickly through this code in pdb
is to set a temporary breakpoint on the line after the loop, which is
inconvenient..
There is a SF bug report #1248119 about this behavior.
Solution:
Should pdb's next command accept an optional numeric argument? It would
specify how many actual lines of code (not "line events")
should be skipped in the current frame before stopping,
i.e "next 5" would mean stop when
line>=line_where_next_N_happened+5
is reached.
This would allow to easily get over/out of loops in the debugger
What do you think?
Ilya
Hello,
This patch is about to celebrate its second birthday :-)
https://sourceforge.net/tracker/?func=detail&atid=305470&aid=790710&group_i…
It seems from the comments that the feature is nice but the
implementation was not OK.
I redid the implem according to the comments.
What should I do to get it reviewed further ? (perhaps just this :
posting to python-dev :-)
Best,
--
Grégoire
Hi,
I'm having 2 problems with the current cvs :
During compilation this warning occurs:
*** WARNING: renaming "dbm" since importing it failed: build/lib.linux-i686-2.5/
dbm.so: undefined symbol: dbm_firstkey
and the 'dbm' module is unavailable.
I'm running MandrakeLinux 2005 (10.2) gcc 3.4.3
(I'm also having this problem when compiling python 2.3.5 or 2.4.1)
furthermore the 'make install' of current cvs fails halfway trough
with the following errors:
.....
.....
Compiling /opt/python25/lib/python2.5/bsddb/test/test_associate.py ...
Sorry: TabError: ('inconsistent use of tabs and spaces in indentation',
('/opt/python25/lib/python2.5/bsddb/test/test_associate.py', 97, 23, '\t
os.mkdir(homeDir)\n'))
Compiling /opt/python25/lib/python2.5/bsddb/test/test_basics.py ...
Sorry: TabError: ('inconsistent use of tabs and spaces in indentation',
('/opt/python25/lib/python2.5/bsddb/test/test_basics.py', 400, 26, '\t if
get_raises_error:\n'))
Compiling /opt/python25/lib/python2.5/bsddb/test/test_compare.py ...
Sorry: TabError: ('inconsistent use of tabs and spaces in indentation',
('/opt/python25/lib/python2.5/bsddb/test/test_compare.py', 167, 5, '\t"""\n'))
.....
.....
Compiling /opt/python25/lib/python2.5/bsddb/test/test_recno.py ...
Sorry: TabError: ('inconsistent use of tabs and spaces in indentation',
('/opt/python25/lib/python2.5/bsddb/test/test_recno.py', 38, 46, '\tget_returns_none =
d.set_get_returns_none(2)\n'))
.....
.....
make: *** [libinstall] Error 1
$
And then it quits.
Fixing the tab indentation errors locally makes the problem go away.
Regards,
Irmen de Jong
[Christoph, please keep the python-dev list in the loop here, at least
until they get annoyed and decide we're off-topic. I think this is
crucial to the way they package and deliver Python]
Christoph Ludwig <cludwig(a)cdc.informatik.tu-darmstadt.de> writes:
> On Thu, Jul 07, 2005 at 06:27:46PM -0400, David Abrahams wrote:
>> "Martin v. Löwis" <martin(a)v.loewis.de> writes:
>>
>> > David Abrahams wrote:
>> >> I'm wondering if there has been a well-known recent change either in Python
>> >> or GCC that would account for these new reports. Any relevant
>> >> information would be appreciated.
> [...]
>> > Python is linked with g++ if configure thinks this is necessary
>>
>> Right. The question is, when should configure "think it's necessary?"
>
> Just to add to the confusion... I encountered the case that configure decided
> to use gcc for linking but it should have used g++. (It is Python
> PR #1189330 <http://tinyurl.com/dlheb>. This was on a x86 Linux system with
> g++ 3.4.2.)
>
> Background: The description of --with-cxx in the README of the
> Python 2.4.1 source distribution made me think that I need to
> configure my Python installation with
> --with-configure=/opt/gcc/gcc-3.4.2/bin/g++ if I plan to use C++
> extensions built with this compiler. (That was possibly a
> misunderstanding on my part,
AFAICT, yes.
> but Python should build with this option anyway.)
>
> configure set `LINKCC=$(PURIFY) $(CC)'. The result was that make failed when
> linking the python executable due to an unresolved reference to
> __gxx_personality_v0. I had to replace CC by CXX in the definition of LINKCC
> to finish the build of Python.
>
> When I looked into this problem I saw that configure in fact builds a test
> executable that included an object file compiled with g++. If the link step
> with gcc succeeds then LINKCC is set as above, otherwise CXX is
> used. Obviously, on my system this test was successful so configure decided
> to link with gcc. However, minimal changes to the source of the test program
> caused the link step to fail. It was not obvious to me at all why the latter
> source code should cause a dependency on the C++ runtime if the original
> code does not. My conclusion was that this test is fragile and should be
> skipped.
Sounds like it. I have never understood what the test was really
checking for since the moment it was first described to me, FWIW.
> If Python is built with --with-cxx then it should be linked with CXX
> as well.
U betcha.
> I gather from posts on the Boost mailing lists that you can import
> Boost.Python extensions even if Python was configured
> --without-cxx.
Yes, all the tests are passing that way.
> (On ELF based Linux/x86, at least.) That leaves me wondering
>
> * when is --with-cxx really necessary?
I think it's plausible that if you set sys.dlopenflags to share
symbols it *might* end up being necessary, but IIRC Ralf does use
sys.dlopenflags with a standard build of Python (no
--with-cxx)... right, Ralf?
> * what happens if I import extensions built with different g++ versions? Will
> there be a conflict between the different versions of libstdc++ those
> extensions depend on?
Not unless you set sys.dlopenflags to share symbols.
It's conceivable that they might conflict through their shared use of
libboost_python.so, but I think you have to accept that an extension
module and the libboost_python.so it is linked with have to be built
with compatible ABIs anyway. So in that case you may need to make
sure each group of extensions built with a given ABI use their own
libboost_python.so (or just link statically to libboost_python.a if
you don't need cross-module conversions).
HTH,
--
Dave Abrahams
Boost Consulting
www.boost-consulting.com
As promised, here is a full set of real-world comparative code
transformations using str.partition(). The patch isn't intended to be
applied; rather, it is here to test/demonstrate whether the new
construct offers benefits under a variety of use cases.
Overall, I found that partition() usefully encapsulated commonly
occurring low-level programming patterns. In most cases, it completely
eliminated the need for slicing and indices. In several cases, code was
simplified dramatically; in some, the simplification was minor; and in a
few cases, the complexity was about the same. No cases were made worse.
Most patterns using str.find() directly translated into an equivalent
using partition. The only awkwardness that arose was in cases where the
original code had a test like, "if s.find(pat) > 0". That case
translated to a double-term test, "if found and head". Also, some
pieces of code needed a tail that included the separator. That need was
met by inserting a line like "tail = sep + tail". And that solution led
to a minor naming discomfort for the middle term of the result tuple, it
was being used as both a Boolean found flag and as a string containing
the separator (hence conflicting the choice of names between "found" and
"sep").
In most cases, there was some increase in efficiency resulting fewer
total steps and tests, and from eliminating double searches. However,
in a few cases, the new code was less efficient because the fragment
only needed either the head or tail but not both as provided by
partition().
In every case, the code was clearer after the transformation. Also,
none of the transformations required str.partition() to be used in a
tricky way. In contrast, I found many contortions using str.find()
where I had to diagram every possible path to understand what the code
was trying to do or to assure myself that it worked.
The new methods excelled at reducing cyclomatic complexity by
eliminating conditional paths. The methods were especially helpful in
the context of multiple finds (i.e. split at the leftmost colon if
present within a group following the rightmost forward slash if
present). In several cases, the replaced code exactly matched the pure
python version of str.partition() -- this confirms that people are
routinely writing multi-step low-level in-line code that duplicates was
str.partition() does in a single step.
The more complex transformations were handled by first figuring out
exactly was the original code did under all possible cases and then
writing the partition() version to match that spec. The lesson was that
it is much easier to program from scratch using partition() than it is
to code using find(). The new method more naturally expresses a series
of parsing steps interleaved with other code.
With further ado, here are the comparative code fragments:
Index: CGIHTTPServer.py
===================================================================
*** 106,121 ****
def run_cgi(self):
"""Execute a CGI script."""
dir, rest = self.cgi_info
! i = rest.rfind('?')
! if i >= 0:
! rest, query = rest[:i], rest[i+1:]
! else:
! query = ''
! i = rest.find('/')
! if i >= 0:
! script, rest = rest[:i], rest[i:]
! else:
! script, rest = rest, ''
scriptname = dir + '/' + script
scriptfile = self.translate_path(scriptname)
if not os.path.exists(scriptfile):
--- 106,113 ----
def run_cgi(self):
"""Execute a CGI script."""
dir, rest = self.cgi_info
! rest, _, query = rest.rpartition('?')
! script, _, rest = rest.partition('/')
scriptname = dir + '/' + script
scriptfile = self.translate_path(scriptname)
if not os.path.exists(scriptfile):
Index: ConfigParser.py
===================================================================
*** 599,612 ****
if depth > MAX_INTERPOLATION_DEPTH:
raise InterpolationDepthError(option, section, rest)
while rest:
! p = rest.find("%")
! if p < 0:
! accum.append(rest)
return
! if p > 0:
! accum.append(rest[:p])
! rest = rest[p:]
! # p is no longer used
c = rest[1:2]
if c == "%":
accum.append("%")
--- 599,611 ----
if depth > MAX_INTERPOLATION_DEPTH:
raise InterpolationDepthError(option, section, rest)
while rest:
! head, sep, rest = rest.partition("%")
! if not sep:
! accum.append(head)
return
! rest = sep + rest
! if found and head:
! accum.append(head)
c = rest[1:2]
if c == "%":
accum.append("%")
Index: cgi.py
===================================================================
*** 337,346 ****
key = plist.pop(0).lower()
pdict = {}
for p in plist:
! i = p.find('=')
! if i >= 0:
! name = p[:i].strip().lower()
! value = p[i+1:].strip()
if len(value) >= 2 and value[0] == value[-1] == '"':
value = value[1:-1]
value = value.replace('\\\\', '\\').replace('\\"',
'"')
--- 337,346 ----
key = plist.pop(0).lower()
pdict = {}
for p in plist:
! name, found, value = p.partition('=')
! if found:
! name = name.strip().lower()
! value = value.strip()
if len(value) >= 2 and value[0] == value[-1] == '"':
value = value[1:-1]
value = value.replace('\\\\', '\\').replace('\\"',
'"')
Index: cookielib.py
===================================================================
*** 610,618 ****
def request_port(request):
host = request.get_host()
! i = host.find(':')
! if i >= 0:
! port = host[i+1:]
try:
int(port)
except ValueError:
--- 610,617 ----
def request_port(request):
host = request.get_host()
! _, sep, port = host.partition(':')
! if sep:
try:
int(port)
except ValueError:
***************
*** 670,681 ****
'.local'
"""
! i = h.find(".")
! if i >= 0:
! #a = h[:i] # this line is only here to show what a is
! b = h[i+1:]
! i = b.find(".")
! if is_HDN(h) and (i >= 0 or b == "local"):
return "."+b
return h
--- 669,677 ----
'.local'
"""
! a, found, b = h.partition('.')
! if found:
! if is_HDN(h) and ('.' in b or b == "local"):
return "."+b
return h
***************
*** 1451,1463 ****
else:
path_specified = False
path = request_path(request)
! i = path.rfind("/")
! if i != -1:
if version == 0:
# Netscape spec parts company from reality here
! path = path[:i]
else:
! path = path[:i+1]
if len(path) == 0: path = "/"
# set default domain
--- 1447,1459 ----
else:
path_specified = False
path = request_path(request)
! head, sep, _ = path.rpartition('/')
! if sep:
if version == 0:
# Netscape spec parts company from reality here
! path = head
else:
! path = head + sep
if len(path) == 0: path = "/"
# set default domain
Index: gopherlib.py
===================================================================
*** 57,65 ****
"""Send a selector to a given host and port, return a file with
the reply."""
import socket
if not port:
! i = host.find(':')
! if i >= 0:
! host, port = host[:i], int(host[i+1:])
if not port:
port = DEF_PORT
elif type(port) == type(''):
--- 57,65 ----
"""Send a selector to a given host and port, return a file with
the reply."""
import socket
if not port:
! head, found, tail = host.partition(':')
! if found:
! host, port = head, int(tail)
if not port:
port = DEF_PORT
elif type(port) == type(''):
Index: httplib.py
===================================================================
*** 490,498 ****
while True:
if chunk_left is None:
line = self.fp.readline()
! i = line.find(';')
! if i >= 0:
! line = line[:i] # strip chunk-extensions
chunk_left = int(line, 16)
if chunk_left == 0:
break
--- 490,496 ----
while True:
if chunk_left is None:
line = self.fp.readline()
! line, _, _ = line.partition(';') # strip
chunk-extensions
chunk_left = int(line, 16)
if chunk_left == 0:
break
***************
*** 586,599 ****
def _set_hostport(self, host, port):
if port is None:
! i = host.rfind(':')
! j = host.rfind(']') # ipv6 addresses have [...]
! if i > j:
try:
! port = int(host[i+1:])
except ValueError:
! raise InvalidURL("nonnumeric port: '%s'" %
host[i+1:])
! host = host[:i]
else:
port = self.default_port
if host and host[0] == '[' and host[-1] == ']':
--- 584,595 ----
def _set_hostport(self, host, port):
if port is None:
! host, _, port = host.rpartition(':')
! if ']' not in port: # ipv6 addresses have [...]
try:
! port = int(port)
except ValueError:
! raise InvalidURL("nonnumeric port: '%s'" % port)
else:
port = self.default_port
if host and host[0] == '[' and host[-1] == ']':
***************
*** 976,998 ****
L = [self._buf]
self._buf = ''
while 1:
! i = L[-1].find("\n")
! if i >= 0:
break
s = self._read()
if s == '':
break
L.append(s)
! if i == -1:
# loop exited because there is no more data
return "".join(L)
else:
! all = "".join(L)
! # XXX could do enough bookkeeping not to do a 2nd search
! i = all.find("\n") + 1
! line = all[:i]
! self._buf = all[i:]
! return line
def readlines(self, sizehint=0):
total = 0
--- 972,990 ----
L = [self._buf]
self._buf = ''
while 1:
! head, found, tail = L[-1].partition('\n')
! if found:
break
s = self._read()
if s == '':
break
L.append(s)
! if not found:
# loop exited because there is no more data
return "".join(L)
else:
! self._buf = found + tail
! return "".join(L) + head
def readlines(self, sizehint=0):
total = 0
Index: ihooks.py
===================================================================
*** 426,438 ****
return None
def find_head_package(self, parent, name):
! if '.' in name:
! i = name.find('.')
! head = name[:i]
! tail = name[i+1:]
! else:
! head = name
! tail = ""
if parent:
qname = "%s.%s" % (parent.__name__, head)
else:
--- 426,432 ----
return None
def find_head_package(self, parent, name):
! head, _, tail = name.partition('.')
if parent:
qname = "%s.%s" % (parent.__name__, head)
else:
***************
*** 449,457 ****
def load_tail(self, q, tail):
m = q
while tail:
! i = tail.find('.')
! if i < 0: i = len(tail)
! head, tail = tail[:i], tail[i+1:]
mname = "%s.%s" % (m.__name__, head)
m = self.import_it(head, mname, m)
if not m:
--- 443,449 ----
def load_tail(self, q, tail):
m = q
while tail:
! head, _, tail = tail.partition('.')
mname = "%s.%s" % (m.__name__, head)
m = self.import_it(head, mname, m)
if not m:
Index: locale.py
===================================================================
*** 98,106 ****
seps = 0
spaces = ""
if s[-1] == ' ':
! sp = s.find(' ')
! spaces = s[sp:]
! s = s[:sp]
while s and grouping:
# if grouping is -1, we are done
if grouping[0]==CHAR_MAX:
--- 98,105 ----
seps = 0
spaces = ""
if s[-1] == ' ':
! spaces, sep, tail = s.partition(' ')
! s = sep + tail
while s and grouping:
# if grouping is -1, we are done
if grouping[0]==CHAR_MAX:
***************
*** 148,156 ****
# so, kill as much spaces as there where separators.
# Leading zeroes as fillers are not yet dealt with, as it is
# not clear how they should interact with grouping.
! sp = result.find(" ")
! if sp==-1:break
! result = result[:sp]+result[sp+1:]
seps -= 1
return result
--- 147,156 ----
# so, kill as much spaces as there where separators.
# Leading zeroes as fillers are not yet dealt with, as it is
# not clear how they should interact with grouping.
! head, found, tail = result.partition(' ')
! if not found:
! break
! result = head + tail
seps -= 1
return result
Index: mailcap.py
===================================================================
*** 105,117 ****
key, view, rest = fields[0], fields[1], fields[2:]
fields = {'view': view}
for field in rest:
! i = field.find('=')
! if i < 0:
! fkey = field
! fvalue = ""
! else:
! fkey = field[:i].strip()
! fvalue = field[i+1:].strip()
if fkey in fields:
# Ignore it
pass
--- 105,113 ----
key, view, rest = fields[0], fields[1], fields[2:]
fields = {'view': view}
for field in rest:
! fkey, found, fvalue = field.partition('=')
! fkey = fkey.strip()
! fvalue = fvalue.strip()
if fkey in fields:
# Ignore it
pass
Index: mhlib.py
===================================================================
*** 356,364 ****
if seq == 'all':
return all
# Test for X:Y before X-Y because 'seq:-n' matches both
! i = seq.find(':')
! if i >= 0:
! head, dir, tail = seq[:i], '', seq[i+1:]
if tail[:1] in '-+':
dir, tail = tail[:1], tail[1:]
if not isnumeric(tail):
--- 356,364 ----
if seq == 'all':
return all
# Test for X:Y before X-Y because 'seq:-n' matches both
! head, found, tail = seq.partition(':')
! if found:
! dir = ''
if tail[:1] in '-+':
dir, tail = tail[:1], tail[1:]
if not isnumeric(tail):
***************
*** 394,403 ****
i = bisect(all, anchor-1)
return all[i:i+count]
# Test for X-Y next
! i = seq.find('-')
! if i >= 0:
! begin = self._parseindex(seq[:i], all)
! end = self._parseindex(seq[i+1:], all)
i = bisect(all, begin-1)
j = bisect(all, end)
r = all[i:j]
--- 394,403 ----
i = bisect(all, anchor-1)
return all[i:i+count]
# Test for X-Y next
! head, found, tail = seq.find('-')
! if found:
! begin = self._parseindex(head, all)
! end = self._parseindex(tail, all)
i = bisect(all, begin-1)
j = bisect(all, end)
r = all[i:j]
Index: modulefinder.py
===================================================================
*** 140,148 ****
assert caller is parent
self.msgout(4, "determine_parent ->", parent)
return parent
! if '.' in pname:
! i = pname.rfind('.')
! pname = pname[:i]
parent = self.modules[pname]
assert parent.__name__ == pname
self.msgout(4, "determine_parent ->", parent)
--- 140,147 ----
assert caller is parent
self.msgout(4, "determine_parent ->", parent)
return parent
! pname, found, _ = pname.rpartition('.')
! if found:
parent = self.modules[pname]
assert parent.__name__ == pname
self.msgout(4, "determine_parent ->", parent)
***************
*** 152,164 ****
def find_head_package(self, parent, name):
self.msgin(4, "find_head_package", parent, name)
! if '.' in name:
! i = name.find('.')
! head = name[:i]
! tail = name[i+1:]
! else:
! head = name
! tail = ""
if parent:
qname = "%s.%s" % (parent.__name__, head)
else:
--- 151,157 ----
def find_head_package(self, parent, name):
self.msgin(4, "find_head_package", parent, name)
! head, _, tail = name.partition('.')
if parent:
qname = "%s.%s" % (parent.__name__, head)
else:
Index: pdb.py
===================================================================
*** 189,200 ****
# split into ';;' separated commands
# unless it's an alias command
if args[0] != 'alias':
! marker = line.find(';;')
! if marker >= 0:
! # queue up everything after marker
! next = line[marker+2:].lstrip()
self.cmdqueue.append(next)
! line = line[:marker].rstrip()
return line
# Command definitions, called by cmdloop()
--- 189,200 ----
# split into ';;' separated commands
# unless it's an alias command
if args[0] != 'alias':
! line, found, next = line.partition(';;')
! if found:
! # queue up everything after command separator
! next = next.lstrip()
self.cmdqueue.append(next)
! line = line.rstrip()
return line
# Command definitions, called by cmdloop()
***************
*** 217,232 ****
filename = None
lineno = None
cond = None
! comma = arg.find(',')
! if comma > 0:
# parse stuff after comma: "condition"
! cond = arg[comma+1:].lstrip()
! arg = arg[:comma].rstrip()
# parse stuff before comma: [filename:]lineno | function
- colon = arg.rfind(':')
funcname = None
! if colon >= 0:
! filename = arg[:colon].rstrip()
f = self.lookupmodule(filename)
if not f:
print '*** ', repr(filename),
--- 217,232 ----
filename = None
lineno = None
cond = None
! arg, found, cond = arg.partition(',')
! if found and arg:
# parse stuff after comma: "condition"
! arg = arg.rstrip()
! cond = cond.lstrip()
# parse stuff before comma: [filename:]lineno | function
funcname = None
! filename, found, arg = arg.rpartition(':')
! if found:
! filename = filename.rstrip()
f = self.lookupmodule(filename)
if not f:
print '*** ', repr(filename),
***************
*** 234,240 ****
return
else:
filename = f
! arg = arg[colon+1:].lstrip()
try:
lineno = int(arg)
except ValueError, msg:
--- 234,240 ----
return
else:
filename = f
! arg = arg.lstrip()
try:
lineno = int(arg)
except ValueError, msg:
***************
*** 437,445 ****
return
if ':' in arg:
# Make sure it works for "clear C:\foo\bar.py:12"
! i = arg.rfind(':')
! filename = arg[:i]
! arg = arg[i+1:]
try:
lineno = int(arg)
except:
--- 437,443 ----
return
if ':' in arg:
# Make sure it works for "clear C:\foo\bar.py:12"
! filename, _, arg = arg.rpartition(':')
try:
lineno = int(arg)
except:
Index: rfc822.py
===================================================================
*** 197,205 ****
You may override this method in order to use Message parsing
on tagged
data in RFC 2822-like formats with special header formats.
"""
! i = line.find(':')
! if i > 0:
! return line[:i].lower()
return None
def islast(self, line):
--- 197,205 ----
You may override this method in order to use Message parsing
on tagged
data in RFC 2822-like formats with special header formats.
"""
! head, found, tail = line.partition(':')
! if found and head:
! return head.lower()
return None
def islast(self, line):
***************
*** 340,348 ****
else:
if raw:
raw.append(', ')
! i = h.find(':')
! if i > 0:
! addr = h[i+1:]
raw.append(addr)
alladdrs = ''.join(raw)
a = AddressList(alladdrs)
--- 340,348 ----
else:
if raw:
raw.append(', ')
! head, found, tail = h.partition(':')
! if found and head:
! addr = tail
raw.append(addr)
alladdrs = ''.join(raw)
a = AddressList(alladdrs)
***************
*** 859,867 ****
data = stuff + data[1:]
if len(data) == 4:
s = data[3]
! i = s.find('+')
! if i > 0:
! data[3:] = [s[:i], s[i+1:]]
else:
data.append('') # Dummy tz
if len(data) < 5:
--- 859,867 ----
data = stuff + data[1:]
if len(data) == 4:
s = data[3]
! head, found, tail = s.partition('+')
! if found and head:
! data[3:] = [head, tail]
else:
data.append('') # Dummy tz
if len(data) < 5:
Index: robotparser.py
===================================================================
*** 104,112 ****
entry = Entry()
state = 0
# remove optional comment and strip line
! i = line.find('#')
! if i>=0:
! line = line[:i]
line = line.strip()
if not line:
continue
--- 104,110 ----
entry = Entry()
state = 0
# remove optional comment and strip line
! line, _, _ = line.partition('#')
line = line.strip()
if not line:
continue
Index: smtpd.py
===================================================================
*** 144,156 ****
self.push('500 Error: bad syntax')
return
method = None
! i = line.find(' ')
! if i < 0:
! command = line.upper()
arg = None
else:
! command = line[:i].upper()
! arg = line[i+1:].strip()
method = getattr(self, 'smtp_' + command, None)
if not method:
self.push('502 Error: command "%s" not implemented' %
command)
--- 144,155 ----
self.push('500 Error: bad syntax')
return
method = None
! command, found, arg = line.partition(' ')
! command = command.upper()
! if not found:
arg = None
else:
! arg = tail.strip()
method = getattr(self, 'smtp_' + command, None)
if not method:
self.push('502 Error: command "%s" not implemented' %
command)
***************
*** 495,514 ****
usage(1, 'Invalid arguments: %s' % COMMASPACE.join(args))
# split into host/port pairs
! i = localspec.find(':')
! if i < 0:
usage(1, 'Bad local spec: %s' % localspec)
! options.localhost = localspec[:i]
try:
! options.localport = int(localspec[i+1:])
except ValueError:
usage(1, 'Bad local port: %s' % localspec)
! i = remotespec.find(':')
! if i < 0:
usage(1, 'Bad remote spec: %s' % remotespec)
! options.remotehost = remotespec[:i]
try:
! options.remoteport = int(remotespec[i+1:])
except ValueError:
usage(1, 'Bad remote port: %s' % remotespec)
return options
--- 494,513 ----
usage(1, 'Invalid arguments: %s' % COMMASPACE.join(args))
# split into host/port pairs
! head, found, tail = localspec.partition(':')
! if not found:
usage(1, 'Bad local spec: %s' % localspec)
! options.localhost = head
try:
! options.localport = int(tail)
except ValueError:
usage(1, 'Bad local port: %s' % localspec)
! head, found, tail = remotespec.partition(':')
! if not found:
usage(1, 'Bad remote spec: %s' % remotespec)
! options.remotehost = head
try:
! options.remoteport = int(tail)
except ValueError:
usage(1, 'Bad remote port: %s' % remotespec)
return options
Index: smtplib.py
===================================================================
*** 276,284 ****
"""
if not port and (host.find(':') == host.rfind(':')):
! i = host.rfind(':')
! if i >= 0:
! host, port = host[:i], host[i+1:]
try: port = int(port)
except ValueError:
raise socket.error, "nonnumeric port"
--- 276,283 ----
"""
if not port and (host.find(':') == host.rfind(':')):
! host, found, port = host.rpartition(':')
! if found:
try: port = int(port)
except ValueError:
raise socket.error, "nonnumeric port"
Index: urllib2.py
===================================================================
*** 289,301 ****
def add_handler(self, handler):
added = False
for meth in dir(handler):
! i = meth.find("_")
! protocol = meth[:i]
! condition = meth[i+1:]
!
if condition.startswith("error"):
! j = condition.find("_") + i + 1
! kind = meth[j+1:]
try:
kind = int(kind)
except ValueError:
--- 289,297 ----
def add_handler(self, handler):
added = False
for meth in dir(handler):
! protocol, _, condition = meth.partition('_')
if condition.startswith("error"):
! _, _, kind = condition.partition('_')
try:
kind = int(kind)
except ValueError:
Index: zipfile.py
===================================================================
*** 117,125 ****
self.orig_filename = filename # Original file name in
archive
# Terminate the file name at the first null byte. Null bytes in file
# names are used as tricks by viruses in archives.
! null_byte = filename.find(chr(0))
! if null_byte >= 0:
! filename = filename[0:null_byte]
# This is used to ensure paths in generated ZIP files always use
# forward slashes as the directory separator, as required by the
# ZIP format specification.
--- 117,123 ----
self.orig_filename = filename # Original file name in
archive
# Terminate the file name at the first null byte. Null bytes in file
# names are used as tricks by viruses in archives.
! filename, _, _ = filename.partition(chr(0))
# This is used to ensure paths in generated ZIP files always use
# forward slashes as the directory separator, as required by the
# ZIP format specification.
Most of the changes in PEP 3000 are tightening up of "There should be
one obvious way to do it.":
* Remove multiple forms of raising exceptions, leaving just "raise instance"
* Remove exec as statement, leaving the compatible tuple/call form.
* Remove <>, ``, leaving !=, repr
etc.
Other changes are to disallow things already considered poor style like:
* No assignment to True/False/None
* No input()
* No access to list comprehension variable
And there is also completely new stuff like static type checking.
While a lot of existing code will break on 3.0 it is still generally
possible to write code that will run on both 2.x and 3.0: use only the
"proper" forms above, do not assume the result of zip or range is a
list, use absolute imports (and avoid static types, of course). I
already write all my new code this way.
Is this "common subset" a happy coincidence or a design principle?
Not all proposed changes remove redundancy or add completely new
things. Some of them just change the way certain things must be done.
For example:
* Moving compile, id, intern to sys
* Replacing print with write/writeln
And possibly the biggest change:
* Reorganize the standard library to not be as shallow
I'm between +0 and -1 on these. I don't find them enough of an
improvement to break this "common subset" behavior. It's not quite the
same as strict backward compatibility and I find it worthwhile to try
to keep it.
Writing programs that run on both 2.x and 3 may require ugly
version-dependent tricks like:
try:
compile
except NameError:
from sys import compile
or perhaps
try:
import urllib
except ImportError:
from www import urllib
Should the "common subset" be a design principle of Python 3? Do
compile and id really have to be moved from __builtins__ to sys? Could
the rearrangement of the standard library be a bit less aggressive and
try to leave commonly used modules in place?
Oren
OK, once the cron job comes around and is run,
http://www.python.org/peps/pep-0348.html will not be a 404 but be the
latest version of the PEP.
Differences since my last public version is that it has
BaseException/Exception as the naming hierarchy, Warning inherits from
Exception, UserException is UserError, and StandardError inherits from
Exception. I also added better annotations on the tree for noticing
where inheritance changed and whether it become broader (and thus had
a new exception in its MRO) or more restrictive (and thus lost an
exception). Basically everything that Guido has brought up today
(08-03).
I may have made some mistakes changing over to BaseException/Exception
thanks to their names being so similar and tossing back in
StandardError so if people catch what seems like odd sentences that is
why (obviously let me know of the mistake).
-Brett
