On Mon, Nov 2, 2009 at 6:48 AM, Jason Grout <jason-s...@creativetrax.com> wrote:
>
> William Stein wrote:
>> On Sun, Nov 1, 2009 at 11:09 PM, Stan Schymanski <schym...@gmail.com> wrote:
>>> I would love to have a script that converts old names in a whole
>>> worksheet to new names. Every time someone deprecates an old name, he
>>> could add the relevant line to the script.
>>>
>>> Would that be possible? What I would love even more, is a notebook
>>> conversion function such as the one that converted my old notebook to
>>> the sage 4.2 format, but I suppose this is not possible for more
>>> complicated changes than just names. MMA asks the user to "Scan notebook
>>> for possible issues" if you open an old notebook with a new version of
>>> MMA, but this is not always helpful.
>>
>> Wow, this is the most interesting suggestion I've heard so far related
>> to deprecation and renaming of functions in Sage. It would be great
>> if we had a framework for doing the above... if it's possible. It's
>> hard to imagine how it could be though, given how incredibly dynamic
>> Python is. It seems like the easiest thing is to just run your code
>> and view the deprecation warnings that are emitted. This would work
>> so long as we never remove anything we deprecate, which seems silly.
>>
>> So, it would be cool to have something like you describe, but I have
>> no idea how to implement it, or even if it is possible.
>
>
> Could we use the compiler module
> (http://docs.python.org/library/compiler.html) to parse the file and
> walk the nodes in the ast, replacing or modifying things as needed?
>
Because of "duck typing" I don't see how such an approach can ever
work. Suppose a I write a function like this:
def f(n):
return n.squarefree_part()
Right now, squarefree_part is a method of some things, e.g., integers.
It _could_ also be a method of polynomials (it isn't now, but imagine
it is). Suppose that it is a method on say 5 different types of
objects in Sage. Suppose we deprecate it as a method on integers.
Now I run that through some script that is supposed to tell me if the
above code needs to be changed. It's tricky, because it *does* need
to change if n is an integer, but it better not change if n is a
polynomial.
Regarding deprecation, we already hashed this out in a previous thread
quite some time ago.
* Use the official deprecation(...) function when deprecating a function.
* We can tell precisely what is deprecated and when by simply
looking at the source code and using the revision control system
and/or comments in the source code. Thus it's completely unnecessary
bureaucracy to require people to open extra tickets just for this, as
was suggested elsewhere in this thread.
* After one year we are allowed to remove deprecated code, but we
only actually do so at major releases (e.g., 5.0, 6.0, 7.0 etc.)
Thus Sage-5.0 *will* remove deprecated code that was deprecated at
least a year ago.
-- William
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