On Fri, Apr 1, 2011 at 2:22 AM, Simon King <simon.k...@uni-jena.de> wrote: > Hi Robert, > > On 1 Apr., 10:25, Robert Bradshaw <rober...@math.washington.edu> > wrote: >> A conversion is like a cast, which tries to make the object if it >> makes sense at all. This is useful, for example, during construction. >> E.g. there's a conversion QQ -> ZZ, list -> QQ[x], or even str -> ZZ. >> They are invoked with __call__. Coercions are the set of conversions >> that happen automatically and implicitly, e.g. during arithmetic. We >> don't want to support str + ZZ, and ZZ coerces to QQ but not the other >> way around. > > OK. So, say, the map from the base ring into a polynomial ring or > matrix algebra or [etc pp] should be registered as a coercion, not as > a conversion, right?
Yep. > If I am not mistaken, one can register a conversion even if a > conversion has been registered before (in contrast to the attempt to > register another coercion). Is that intended? Probably not. >> No, I don't think there's anything like that yet. > > OK, done. > > This will be on #9138. > > Cheers, > Simon > > -- > To post to this group, send an email to sage-devel@googlegroups.com > To unsubscribe from this group, send an email to > sage-devel+unsubscr...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/sage-devel > URL: http://www.sagemath.org > -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
