Am 28.09.2012 20:42, schrieb Aaron Meurer:
I agree that C is probably not necessary, and really is not necessary
to be included in "from sympy import *". So I'm +1 to remove it,
unless we determine that it really is needed. Should we deprecate it
first, or just remove it?
+1 to deprecate, -1 to remove.
Removal runs the risk of enraging people who use C and can't quickly
change their code.
Deprecation would be enough for inside SymPy: the warnings happen in the
call site, which is what's getting changed anyway.
S on the other hand is quite useful. Because the members are
singletonized, you can use "is" comparison (much faster than ==
comparison).
That's generally true for each singleton.
I'd suggest moving the singletons into the classes where they're created.
> But this only works if you have the element itself, so
for example, if you want to compare against 0, you have to first
sympify 0. "a is S.Zero" is the cleanest way to do this. I'm also
rather fond of the tab-completeable shortcut for 1/2 by S.Half in
interactive use.
Hm... Zero could be a class.
This is Python, things can be class, function, and dictionary all at once.
Also, unlike C, S only eats up those objects that specifically set it
as their metaclass. So the name clash issue that Ronan mentioned does
not apply. I also seriously doubt any external code uses S to create
its own singletons, though something like that would be perfectly
acceptable and supported, so long as the names don't clash with
existing names.
They may clash with names created by other people who're using SymPy, so
freely combining code written by others isn't possible anymore.
Also, they may clash with names that future versions of SymPy place in S.
For this reason, adding stuff to S by anybody other than the SymPy team
would actually be a bad idea IMNSHO.
Just my thoughts.
Regards,
Jo
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