On Wed, Feb 18, 2009 at 3:58 PM, Nick Alexander <ncalexan...@gmail.com> wrote: > > > On 18-Feb-09, at 3:30 PM, Nicolas M. Thiery wrote: > >> >> Dear Robert, >> >> On Sat, Feb 14, 2009 at 03:57:07PM -0800, Robert Bradshaw wrote: >>> ... >>>> Would it be possible to add the following functionality (with >>>> whatever >>>> appropriate syntax): >>>> >>>> declare_conversion(source, target, morphism) >>>> >>>> which would adds the morphism from source to target to the >>>> conversion >>>> list (and probably similarly for coercions). Having some >>>> restrictions >>>> on it (like making sure it's called before any coercion/conversion >>>> is >>>> attempted) is no problem. > > Just for the record, this is exactly what I need. It's kind of > already there: you can call ._populate_coercion_lists_() with new > information and it will do its best to do what you want. Of course, > it's risky because the coercion graph isn't always updated correctly, > but in my situations it works reasonably well. > > Nick
Could you give an example. There's nothing like a list of "Evil Tricks with ... that you should never do" to help people learn things. I just tried to play around with _populate_coercion_lists_ to do some evil things (e.g., make an automatic coercion from QQ to GF(13)), but only ended up causing an infinite loop... William --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send email to sage-devel-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
