[Python-Dev] PEP 303: Extend divmod() for Multiple Divisors

[Christian Tismer]

Guido van Rossum wrote:
...

> I find
> 
>   mm, ss = divmod(ss, 60)
> 
> easier to read than
> 
>   mm, ss = ss//60, ss%60

Before I retract completely, I have a small addition.

   mm = ss//60; ss %= 60

is very readable to me, very efficient, and doesn't use
extra tuples. It is also 2 characters shorter than the
divmod version (both with the usual spacing, of course).
On the other hand, divmod clearly says what is going to
happen, and in fact it is a higher level approach.

On dropping features, I came to this in the morning:

You said you might optimize certain builtins by the
compiler, instead of removing divmod.

How about this:
If divmod is supported by the compiler, there isn't
any reason to keep it as a compiled C module. Instead,
divmod could be a piece of Python code, which is
injected into builtins somewhere at startup time.
Since he compiler supports it, it just needs to be
there at all, but does not need to waste space in
the Python executable.

I'm not saying this just to fight divmod out of the
language. This is ridiculous. But in the long term,
there might be quite a lot of redundancy introduced
by enhanced versions of the compiler. Instead of
letting the code grow on and on, I'd like to propose
some shrinking attempt like in this case.
If the compiler eats 95 percent of calls to some code
already, I believe it makes sense to replace that
piece of code by Python code and drop the C version.

The smaller the C code base, the better for Python.
Less static code also improves the effect of compilers
like Psyco. Let's make a smaller and better kernel.
Get rid of ballast and have less code to maintain.

This is a real wish and *no* Silvester joke :-)

cheers - chris

-- 
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