[Python-Dev] Changes to decimal.py

[Facundo Batista]

Raymond Hettinger wrote:

> As promised in the decimal.py header, the spec
> updates should all be considered as bugs and backported at some point
> after they are fully tested and we're happy with them all around.  
> Also, as promised, the module should continue to run on Py2.3.

Ok. So far, I'm dealing just with this. decimal.py passes, for example,
the old quantize.decTest, but not the new one.

My first step in this journey is to get the new test cases pass ok.


> For the most part, many of the new operations can be implemented in terms
> of the existing ops or in terms of the support functions that we
> already use internally.  Ideally, you can refactor common code while
> leaving almost all of the exisiting algorithm implementation code
> untouched.

Yes. Some of the existing code will be touched, but mostly for bug
fixing.


> The spec's choice of new method names is unfortunate.  You'll have to
> come-up with something better than copy() and class().

The names, as the new functions will be discussed here in the second
step. For example, I'm not absolute sure that something like...

>>> Decimal("1100").xor(Decimal("0110")
Decimal("1010")

...is actually needed.


> FWIW, I think the new decimal development should probably be done in a
> branch off of the current head.  That way, you can check-in at will
> and get feedback from everyone without risking the integrity of the head.

This is a very good idea.


> If you want to discuss anything during development, I'm usually available on
> AOL instant messaging with the screename:  raymondewt
>
> Likewise, consider soliciting Tim's input on how to implement the ln() operation.
>  That one will be tricky to get done efficiently and correctly.

Great, thank you!!

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