[docs] Need Programming FAQ entry for the behavior of closures (issue 13094)

[rdmurray at bitdance.com]

Thanks for writing this.  Overall it looks good, but I did some copy
editing.  Only two substantive comments.


http://bugs.python.org/review/13094/diff/6975/Doc/faq/programming.rst
File Doc/faq/programming.rst (right):

http://bugs.python.org/review/13094/diff/6975/Doc/faq/programming.rst#newcode219
Doc/faq/programming.rst:219: This gives you a list that contains 5
lambdas that calculate ``x**2``, and you
...``x**2``.  You...

http://bugs.python.org/review/13094/diff/6975/Doc/faq/programming.rst#newcode220
Doc/faq/programming.rst:220: might expect that, when called, they would
return respectively ``0``, ``1``,
commas around respectively (IMO)

http://bugs.python.org/review/13094/diff/6975/Doc/faq/programming.rst#newcode221
Doc/faq/programming.rst:221: ``4``, ``9``, and ``16``.  However, when
you actually try, you will see that
I think the comma after try is unnecessary and a bit distracting (though
not technically wrong).

http://bugs.python.org/review/13094/diff/6975/Doc/faq/programming.rst#newcode229
Doc/faq/programming.rst:229: This happens because ``x`` is not local to
the lambdas, but it's defined in
is instead of "it's".

http://bugs.python.org/review/13094/diff/6975/Doc/faq/programming.rst#newcode230
Doc/faq/programming.rst:230: the global scope, and it's accessed when
the lambda is called --- not when it's
How about you just say "outer scope" here, which will cover the case of
referencing a local inside a function.

http://bugs.python.org/review/13094/diff/6975/Doc/faq/programming.rst#newcode230
Doc/faq/programming.rst:230: the global scope, and it's accessed when
the lambda is called --- not when it's
I would prefer spelling out 'it is' here.

http://bugs.python.org/review/13094/diff/6975/Doc/faq/programming.rst#newcode233
Doc/faq/programming.rst:233: changing the value of ``x`` and see how the
result of the lambdas changes::
changes should be change.  Probably result should be results.

http://bugs.python.org/review/13094/diff/6975/Doc/faq/programming.rst#newcode246
Doc/faq/programming.rst:246: Here, ``n=x`` creates a new variable ``n``
local to the lambda, with the
Rather than say "local to the lambda", I think it would be more correct
to say "whose value is computed when the lambda is defined", which is
what is really going on here.

http://bugs.python.org/review/13094/diff/6975/Doc/faq/programming.rst#newcode256
Doc/faq/programming.rst:256: Note that this is not a particular
behaviour of lambdas, but it applies to
"this behavior is not peculiar to lambdas, but applies..."

http://bugs.python.org/review/13094/