On 08/07/2010 02:45, Terry Reedy wrote:
On 7/7/2010 2:42 PM, Antoine Pitrou wrote:
I wrote
4. Does not ctypes make it possible to replace a method of a
Python-coded
class with a faster C version, with something like
try:
connect to methods.dll
methods.dll to be written
check that function xyx exists
replace Someclass.xyy with ctypes wrapper
except: pass
For instance, the SequenceMatcher heuristic was added to speedup the
matching process that I believe is encapsulated in one O(n**2) or so
bottleneck method. I believe most everything else is O(n) bookkeeping.
Except that ctypes doesn't help provide C extensions at all. It only
helps provide wrappers around existing C libraries, which is quite a
different thing.
Which, in the end, makes the original suggestion meaningless.
To you, so let me restate it. It would be easier for many people to
only rewrite, for instance,
difflib.SequenceMatcher.get_longest_matching in C than to rewrite the
whole SequenceMatcher class, let alone the whole difflib module.
I got the impression from the datetime issue tracker discussion that
it is not possible to replace a single method of a Python-coded class
with a C version. I got this from statement that seems to say that
having parallel Python and C versions is a nuisance because one must
replace large chunks of Python, at least a class if not the whole
module. If that impression is wrong, and I hope it is, the suggestion
is unnecessary.
If it is right, then replacing the Python-coded function with a
Python-coded wrapper for a function in a miscellaneous shared library
might be both possible and useful. But again, if the premise is wrong,
skip the conclusion.
Would it be possible to provide a single method in C by providing a C
base class with a single method and have the full implementation inherit
from the C base class if it is available or otherwise a pure Python base
class?
Michael
--
http://www.ironpythoninaction.com/
http://www.voidspace.org.uk/blog
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