On 8/12/2012 7:06 PM, kj wrote:
Is there an *explicitly stated* reason (e.g. in a PEP, or in some
python dev list message) for why the inspect module (at least for
Python 2.7)
2.7 is over two years old. Things have been added to the inspect module
since. So when asking about 'why feature x is not present', you should
be asking about 3.3. Enhancement requests should be directed to 3.4.
does not include anything like a "currentcallable()"
3.x include currentframe() (see below), though it is not guaranteed for
anything other than CPython. 2.x and 3.x have more general functions to
get the entire call stack. Details are certainly implementation specific.
function that would *stably*[1] return the currently executing
callable object?
The concepts 'callable' and 'executable' are not the same. Callables
have a .__call__ method that initiates the execution of an executable.
Python-coded functions have a __call__ method that knows how to initiate
the execution of the attached (byte)code object that was compiled from
the Python code. C-coded function wrappers have a __call__ method that
knows how to initiate the execution of object code compiled from C
functions. Other implementations have other __call__ methods. Once the
executable is executing, there is no need for the function and its call
method.
So getting the current callable has to be indirect frame to code object
to name to function object looked up in the parent calling frame. A
direct link would create an unnecessary circular reference.
[1] By "stably" above I mean, e.g., that the value returned by the
top-level function (object) defined by
def spam():
return inspect.currentcallable()
is *invariant*, in contrast to the value returned by the top-level
function (object) defined by
There have been various proposals and a rejected PEP for accessing 'this
function' from within a function. I do not know if that particular
spelling has been proposed or not.
def ham():
return ham
which is whatever the current value of the 'ham' global happens to
be.
if the def statement is in global scope.
There is no difference unless someone rebind the name, which is normally
done intentionally, for a purpose. Names do not just randomly mutate.
The advantage of access by name is that if someone, whether the original
author or not, wraps the function (say to log calls), then the function
continues to work with the wrapped version.
--
Terry Jan Reedy
--
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