On Tue, Mar 27, 2012 at 10:29:12AM -0700, Starx wrote:
> ...
+1 on reducing the number of is_... functions.
> As for the other 150, some of them do the following:
>
> def is_Name(x)
> return isinstance(x, Name_something)
>
> I didn't check but I suspect that there is a factory called Name which
> is why the _whatever is there.
Precisely for this purpose, we (Florent, me, ...) are in favor, in
such situation, of merging the factory "Name" and the class
Name_something, so that one can do both:
sage: Name(...)
sage: isinstance(..., Name)
with a single gadget imported by default in sage.all.
See the discussion in ClasscallMetaclass for one way to implement
that, and IntegerRange for an example.
Also, the idiom ``is_Field(P)`` would be best replaced by ``P in Fields()``.
On a related note: with Simon King, we are in favor of keeping both
the two idioms ``P in Fields() and ``P.is_field()``, With slightly
different semantic:
- P in Fields(): is P already known to be a field? I.e. is the
category of P a subcategory of Fields()?
- P.is_field(): decide whether P is a field, possibly running a
costly computation if needed. If the answer is positive, P is
typically upgraded to the Fields() category.
Cheers,
Nicolas
--
Nicolas M. Thiéry "Isil" <nthi...@users.sf.net>
http://Nicolas.Thiery.name/
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