Paul LaFollette wrote:
Kind people,
Using Python 3.1 under FreeBSD and WinXP.
I've been tearing my hair out trying to solve this myself, but I need
to ask for help. I want (for obscure reasons) to be able to log
transactions in the namespace(s) of a script. Specifically I would
like to log creation of identifiers, changes in the binding of
identifiers ("assignment") and lookups. This turns out to be pretty
easy in the global and local namespaces... I simply subclass dict,
override the appropriate operations to include the logging operations
I want, and then exec the code using my dictionaries as the global and
local namespaces. All of this works just dandy until I try to
extend it to functions.
I cannot figure out any way to get a hook into the local namespace of
a user defined function. I have tried making a wrapper class that
grabs the function call and then uses exec to invoke
myfunction.__code__ with my own dictionaries. This runs the (no
argument) function properly (losing the return value, but I can deal
with that) but never accesses the local logging dictionary that I
specify in the exec() call. Perhaps the local namespace of a function
is not a dict at all?
Anyway, is there any way (however clumsy) to do what I want to do?
Thank you for your help.
Paul
---------------------------
Paul LaFollette
CIS Department
Temple University
paul.lafollette(at)temple.edu
www.cis.temple.edu/~lafollet
Is there a way? Undoubtedly.
The simplest way that occurs to me is to have a pre-pass that rewrites
the .pyc files, adding instrumentation to the byte-code. You could also
recompile the Python interpreter, with some extra hooks in it. That
could get tricky, as you don't want to instrument the code that's doing
the tracking. Fnally, you could hook into the byte-code loader, doing
the changes at that time.
As always, if the code is for commercial use, beware of infringing on
patents. I have a few in the 3rd area (though the ownership is with
other companies; I was just the inventor.)
DaveA
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