#19628: lazy_import breaks CachedRepresentation
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Reporter: cheuberg | Owner:
Type: defect | Status: new
Priority: major | Milestone: sage-6.10
Component: coercion | Resolution:
Keywords: | Merged in:
Authors: | Reviewers:
Report Upstream: N/A | Work issues:
Branch: | Commit:
Dependencies: | Stopgaps:
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Comment (by nbruin):
Replying to [comment:26 jdemeyer]:
> Replying to [comment:24 nbruin]:
> > You can of course try to extend the use of lazy_import and see if you
can get it to work for things like NN as well.
>
> I would certainly like to try that. It would be a pity if rings (like
`NN`) are fundamentally incompatible with `lazy_import`. Consider `arb`
for example: it makes sense to define a global `RBF` (for real ball
field), analogous to `RR`. It also makes a lot of sense to lazily import
this: it's unlikely to be commonly used, it would save an import of at
least 2 Python modules and it would save the loading of the external
library `libarb`.
We can do that at the cost of a namespace:
{{{
realballfield.RBF
natural_numbers.NN
}}}
(where `realballfield` and `natural_numbers` can be lazily imported) or at
the cost of an accessor function (lazily imported):
{{{
RealBallField()
NaturalNumbers()
}}}
The fact that
{{{
D=dict()
D[NN]=1
D[NN]=2
}}}
will never work properly makes trying to pretend otherwise a non-starter
in my opinion. You'd have to reach too deeply into python (you probably
wouldn't even be able to distinguish between the "initialization" code
where the Lazy object needs to be passed and genuine access, where you do
need to dereference).
We could reach into various sage infrastructures and special-case
LazyImports there, but in my opinion that would just increase the surprise
factor when other constructs fail.
--
Ticket URL: <http://trac.sagemath.org/ticket/19628#comment:27>
Sage <http://www.sagemath.org>
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