[Python-Dev] New operations in Decimal

Terry Reedy tjreedy at udel.edu
Fri May 11 05:45:31 CEST 2007

"Raymond Hettinger" <python at rcn.com> wrote in message 
news:20070510185924.BIU37629 at ms09.lnh.mail.rcn.net...
| > I oppose adding this illogical nonsense to Python.  Who would ever use 
| Doesn't matter.  What is more important is that we provide a module that 
| fully compliant with the specification and passes all of its tests.  The 
| is in the compliance, not in the relative value of individual parts of 
the spec.

To repeat my further question:  if IBM adds string functions or anything 
else to the 'decimal arithmetic' spec, should we unthinkingly add them 

Is there there no limit to the size of the camel that comes in with the 

Suppose the next edition of the spec contains decimal versions of the 
functions in numpy (BLAS, LINPACK, FTTPACK, and so on).  Should they be 
included in the standard lib even while numpy is excluded.

We supposedly have a standard for additions to the standard lib.  I cannot 
think of any other module being admitted with what amounts to an unlimited 
blank check for further additions.

| This is somewhat akin to modules supporting RFC specs or internet
| protocols.  It is more important to be standard than it is to pick and 
| the parts you like.

My impresssion from reading this list is that some of the modules 
supporting such specs/protocols are not complete and that there has been 
some picking and choosing.  Wasn't there recently discussion about DOM 
level compliance?

 In any case, once RFCs are finalized, they does not, as far as I know, 
grow with additions, sane or crazy.  Nex stuff goes in a new RFC which can 
be evaluated separately against our normal criteria for stdlib additions.

| While I question the sanity of the spec writers in this case, I do trust 
| overall, they have provided an extremely well thought-out spec, have gone
| through extensive discussion/feedback cycles, and have provided a 
| test-suite.  It is as good as it gets.

I had the same opinion until I saw the logic stuff.  But I have known IBM 
and its products, good and bad, for over 40 years, so it does not surprise 
me when they act somewhat imperialistically for commercial advantage.  This 
strikes me as likely such a case.  But I may give M.C. a chance to better 
educate me.

In the meanwhile here is my suggestion.

Segregate the binary digit functions, and anything else of their ilk, in a 
separate module, say decimal_extras, and make it available on PyPI.  In 
decimal, add
    from decimal_extras import *
except ImportError:
Then the tests could pass without junking up the stdlib with stuff that 
would never even be proposed, let alone accepted.

And should I be proved wrong, and these functions find favor with the 
community and usage in production code, then they can be seamlessly moved 
into the stdlib and the decimal module after having met the test of other 

Terry Jan Reedy

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