Re: [Python-Dev] PEP 3147: PYC Repository Directories
On approximately 1/30/2010 4:00 PM, came the following characters from the keyboard of Barry Warsaw:
When the Python executable is given a `-R` flag, or the environment variable `$PYTHONPYR` is set, then Python will create a `foo.pyr` directory and write a `pyc` file to that directory with the hexlified magic number as the base name.
After the discussion so far, my opinion is that if the source directory contains an appropriate python repositiory directory [1], and the version of Python implements PEP 3147, that there should be no need for -R or $PYTHONPYR to exist, but that such versions of Python would simply, and always look in the python repository directory for binaries. I've reached this conclusion for several reasons/benefits: 1) it makes the rules simpler for people finding the binaries 2) there is no "double lookup" to find a binary at run time 3) if the PEP changes to implement alternatives B or C in [1], then I hear a large consensus of people that like that behavior, to clean up the annoying clutter of .pyc files mixed with source. 4) There is no need to add or document the command line option or environment variable. [1] Alternative A... source-file-root.pyr, as in the PEP, Alt. B... source-file-dir/__pyr__ all versions/files in same lookaside directory, Alt. C... source-file-dir/__pyr_version__, each Python version with different bytecode would have some sort of version string or magic number that identifies it, and would look only in that directory for its .pyc/.pyo files. I prefer C for 4 reasons: 1) easier to blow away one version; 2) easier to see what that version has compiled; 3) most people use only one or two versions, so directory proliferation is limited; 4) even when there are 30 versions of Python, the subdirectories would contain the same order-of-magnitude count of files as the source directory for performance issues, if the file system has a knee in the performance curve as some do. -- Glenn -- http://nevcal.com/ =========================== A protocol is complete when there is nothing left to remove. -- Stuart Cheshire, Apple Computer, regarding Zero Configuration Networking
Glenn Linderman wrote:
Alt. C... source-file-dir/__pyr_version__, each Python version with different bytecode would have some sort of version string or magic number that identifies it, and would look only in that directory for its .pyc/.pyo files. I prefer C for 4 reasons: 1) easier to blow away one version; 2) easier to see what that version has compiled; 3) most people use only one or two versions, so directory proliferation is limited; 4) even when there are 30 versions of Python, the subdirectories would contain the same order-of-magnitude count of files as the source directory for performance issues, if the file system has a knee in the performance curve as some do.
I don't think this suggestion had come up before, but I like it. It also reduces the amount of filename adjustment needed in the individual cache directories. Cheers, Nick. -- Nick Coghlan | ncoghlan@gmail.com | Brisbane, Australia ---------------------------------------------------------------
Glenn Linderman wrote:
On approximately 1/30/2010 4:00 PM, came the following characters from the keyboard of Barry Warsaw:
When the Python executable is given a `-R` flag, or the environment variable `$PYTHONPYR` is set, then Python will create a `foo.pyr` directory and write a `pyc` file to that directory with the hexlified magic number as the base name.
After the discussion so far, my opinion is that if the source directory contains an appropriate python repositiory directory [1], and the version of Python implements PEP 3147, that there should be no need for -R or $PYTHONPYR to exist, but that such versions of Python would simply, and always look in the python repository directory for binaries.
How would the python repository directory ever get created?
On approximately 2/4/2010 2:28 PM, came the following characters from the keyboard of Eric Smith:
Glenn Linderman wrote:
On approximately 1/30/2010 4:00 PM, came the following characters from the keyboard of Barry Warsaw:
When the Python executable is given a `-R` flag, or the environment variable `$PYTHONPYR` is set, then Python will create a `foo.pyr` directory and write a `pyc` file to that directory with the hexlified magic number as the base name.
After the discussion so far, my opinion is that if the source directory contains an appropriate python repositiory directory [1], and the version of Python implements PEP 3147, that there should be no need for -R or $PYTHONPYR to exist, but that such versions of Python would simply, and always look in the python repository directory for binaries.
How would the python repository directory ever get created?
When a PEP 3147 (if modified by my suggestion) version of Python runs, and the directory doesn't exist, and it wants to create a .pyc, it would create the directory, and put the .pyc there. Sort of just like how it creates .pyc files, now, but an extra step of creating the repository directory if it doesn't exist. After the first run, it would exist. It is described in the PEP, and I quoted that section... "Python will create a 'foo.pyr' directory"... I'm just suggesting different semantics for how many directories, and what is contained in them. -- Glenn ------------------------------------------------------------------------ “Everyone is entitled to their own opinion, but not their own facts. In turn, everyone is entitled to their own opinions of the facts, but not their own facts based on their opinions.” -- Guy Rocha, retiring NV state archivist
On Feb 04, 2010, at 03:00 PM, Glenn Linderman wrote:
When a PEP 3147 (if modified by my suggestion) version of Python runs, and the directory doesn't exist, and it wants to create a .pyc, it would create the directory, and put the .pyc there. Sort of just like how it creates .pyc files, now, but an extra step of creating the repository directory if it doesn't exist. After the first run, it would exist. It is described in the PEP, and I quoted that section... "Python will create a 'foo.pyr' directory"... I'm just suggesting different semantics for how many directories, and what is contained in them.
I've added __pyr_version__ as an open question in the PEP (not yet committed), as is making this default behavior (no -R flag required). -Barry
participants (5)
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Barry Warsaw -
Eric Smith -
Glenn Linderman -
Glenn Linderman -
Nick Coghlan