I don't think there's much documentation beyond what's in _coerce_map_from_() in Parent.
If it returns re, then it uses _element_constructor_ to construct the morphism. Otherwise you return a morphism. I think there's some examples in src/algebras which returns morphisms (I'm pretty sure I've seen it, definitely wrote some code on it, but I don't remember off-hand for what). Best, Travis -- 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.