Why does linecache avoid <stdin>? How can I get equivalent of inspect.getsource() for an interactive session?

[Mark Hirota]

Here's my goal:

To enable a function for interactive session use that, when invoked,
will "put" source code for a specified object into a plaintext file.
Based on some initial research, this seems similar to ipython's %save
magic command (?)

Example:

def put(filename, object):
    f = open(filename, "w")
    f.write(inspect.getsource(object))
    f.close()

Of course, in an interactive session, if you define a function:

>>> def addit(a,b): return a+b

And then try to run inspect.getsource() on it, you'll get an exception:

>>> inspect.getsource(addit)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:\Python26\lib\inspect.py", line 689, in getsource
    lines, lnum = getsourcelines(object)
  File "C:\Python26\lib\inspect.py", line 678, in getsourcelines
    lines, lnum = findsource(object)
  File "C:\Python26\lib\inspect.py", line 526, in findsource
    raise IOError('could not get source code')
IOError: could not get source code

This appears to be due to the fact that the linecache standard library
module doesn't include <stdin> (?)

Can anyone help shed some light on why this is -- and perhaps provide
feedback on whether this goal is feasible?

Thanks!