[ python-Bugs-672578 ] pydoc does not cope well with lambda

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Bugs item #672578, was opened at 2003-01-22 17:29
Message generated for change (Comment added) made by wamcvey
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Category: Demos and Tools
Group: Python 2.2.1
Status: Closed
Resolution: Fixed
Priority: 5
Submitted By: Jim Meyer (purp)
Assigned to: Nobody/Anonymous (nobody)
Summary: pydoc does not cope well with lambda

Initial Comment:
pydoc doesn't deal well with lambda expressions. Here's
some sample code:
================================================================
#!/usr/bin/env python2
"""a bogus program

Demonstrate that pydoc doesn't handle lambdas well
"""

#
--------------------------------------------------------------------
# A comment heading
#
--------------------------------------------------------------------
def foo (optional = 1) :
	''' A bogus function '''
	return optional

bar = lambda opt : foo(opt)
================================================================

...and here's what pydoc says:

================================================================
> pydoc /tmp/foo.py
Python Library Documentation: module foo

NAME
    foo - a bogus program

FILE
    /tmp/foo.py

DESCRIPTION
    Demonstrate that pydoc doesn't handle lambdas well

FUNCTIONS
    lambdaopt
        #
--------------------------------------------------------------------
        # A comment heading
        #
--------------------------------------------------------------------
    
    foo(optional=1)
         A bogus function

DATA
    __file__ = '/tmp/foo.pyc'
    __name__ = 'foo'

================================================================

I'm looking for the cause now and hope to contribute a
patch shortly.

--j

----------------------------------------------------------------------

Comment By: William McVey (wamcvey)
Date: 2006-02-14 17:14

Message:
Logged In: YES 
user_id=25956

This problem still appears to exist under python 2.4.2

drop the following into PydocLambdaTest.py and run 'pydoc
PydocLambdaTest':

#!/usr/bin/env python

"""Simple test cases for doc strings attached to lambda
generated functions
and methods
"""

def test_function(x, y):
        """This is a test function doc string"""
        pass

test_lambda = lambda x, y: True

test_lambda2 = lambda x, y: True
test_lambda2.__doc__ = "This is a docstring on a lambda
function"


class TestClass:
        def test_method(self, x, y):
                """Just a docstring on a method"""
                pass
        
        sum = lambda self, x, y: x+y

        mult = lambda self, x, y: x*y
        mult.__doc__ = "Multiplies the two arguments "

if __name__ == '__main__':
        obj = TestClass()
        print "sum of 5 and 7:", obj.sum(5, 7)
        print "mult of 5 and 7:", obj.mult(5, 7)


----------------------------------------------------------------------

Comment By: Raymond Hettinger (rhettinger)
Date: 2003-01-23 01:55

Message:
Logged In: YES 
user_id=80475

The underlying cause is that the inspect module was not 
trained to handle lambdas or single line function defintions 
like:

def oneliner(x): return x**2

The problem was fixed in Py2.3 and backported for 
Py2.2.3.

Marking as fixed and closing.

----------------------------------------------------------------------

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