2014-08-26 15:22 UTC+02:00, William A Stein <wst...@uw.edu>: > On Tue, Aug 26, 2014 at 3:12 PM, John Cremona <john.crem...@gmail.com> > wrote: >> Sounds like a reasonable plan if you (or someone) can be bothered to >> sort out the chenges which will need to be made in code and doctests! > > Even then, personally I don't like it. See below for a different > suggestion that is less intrusive. > >> There will be places where we now have: for p in primes(10^8): >> do_something_with(p) which will still work when primes() returns a >> list, so will not result in doctest failures, but which should be >> changed. This will be rather tedious. >> >> On the plus side, I make the point that all these are functions at the >> top level which will be discovered by beginners for whom >> >> sage: primes(100) >> <generator object primes at 0x7f9335465a50> >> >> will just confuse. Experts can know about and use the iterator forms >> of the functions. > > We could certainly make it do this with little effort: > > sage: P = primes(100); P > Prime numbers of less than 100 > > We could then have > > for x in P: > ... > > be the usual iterator. One could also do: > > sage: P.list() > [...] > > to get back a list. And one could do > > sage: len(P) > > to get the number of primes, without computing them. So... my > counterproposal is to make primes return a cython class with a few > methods. This breaks new code, and will be more new user friendly.
We already have Primes (upper case P) for that... it just need to be tuned to accept lower/upper bounds. It is nicer from the user point of view (as far as OOP is better than functional programming). A good solution for the namespace would be to have only Primes and PrimePowers. But I really will not use it myself because it has a classcall, UniqueRepresentation, category, etc which takes lifetime to initialize. My loops are rather small but I have plenty of them... so having a nice Primes object would only be painful. I want to keep a simple Cython function that returns list or iterator. Vincent -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
