Georg Brandl wrote:
> +1. Having a single (visible) __pyr__ directory is much less clutter than
> multiple .pyc files anyway. Also, don't forget Windows users, for whom
> the dot convention doesn't mean anything.
I must admit I quite like the __pyr__ directory approach as well. Since
the interpreter knows the suffix it is looking for, names shouldn't
conflict. Using a single directory allows the name to be less cryptic,
too (e.g. __pycache__).
That still leaves the question of what to do with __file__ (for which
even the solution in the PEP isn't particularly clean). Perhaps the
thing to do there is to have __file__ always point to the source file
and introduce a __file_cached__ that points to the bytecompiled file on
disk (set to None if it doesn't exist, as may be the case for __main__
or due to writing of bytecode files being disabled).
With that approach, a structure given just a run under 2.7 and one under
2.7 with -O might look like:
package/
__init__.py
foo.py
__pycache__/
__init__.cpython-27.pyc
__init__.cpython-27.pyo
foo.cpython-27.pyc
foo.cpython-27.pyo
subpackage/
__init__.py
bar.py
__pycache__/
__init__.cpython-27.pyc
__init__.cpython-27.pyo
bar.cpython-27.pyc
bar.cpython-27.pyo
__file__ would always point to the source files
__file_cached__ would always point to the relevant compiled file (either
pre-existing or newly created)
To use the final step of importing package.foo as an example (ignoring
the extra backwards compatibility steps for the existing scheme):
1. Check package dir listing for __pyr__
2. It it exists, check it for a foo.<cookie>.<ext> (where the
interpreter will always know exactly which cookie and extension it wants)
3. As an CPython implementation details, use the cookie inside the file
to double-check correctness
4. If all good, run with that cached file
5. Otherwise, check package dir for foo.py
6. If the source file exists, create the cached bytecode file inside the
__pyr__ (if this fails, just run from RAM with __file_cached__ = None)
7. Run with the newly compiled source file
8. Otherwise report ImportError.
This doesn't seem to have any significant disadvantages relative to the
subdirectory-per-source-file approach (and the major advantage of
creating just a single subdirectory).
Cheers,
Nick.
--
Nick Coghlan | ncogh...@gmail.com | Brisbane, Australia
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