> If you are proposing to add "<-" and "->" to the fundamental Python > grammar, then it could work as PEP465 does. But if you are proposing > that classes can define new lexical operators, it would have to work > very very differently. You started with "operators as first class > citizens," but I don't know what you mean by that.
It is my bad to mix this two topics together ... I am not strongly proposing for now to have python to support arbitrary operator definitions, I can live with the arrow propose if it makes sense. I see also even the term "first class citizen" makes a confusion here ... by which python do have certain extent of support for the existing operators. What I should have emphasized more is the dynamic nature of creating new operators. Which scala seems does a better job in this area for now. > When Python compiles a file, it does not read the imported files at > all. That doesn't happen until run time. So how will Python know what > "<-" means in circuit.py? It's never seen this token before, so it > can't know what special method it should map onto. It can't even know > what the token is. What if it encounters "x ~++<-+ y"? What are the > tokens in that source? I see your point now. Scala does this by simply looking up a method on the object named as "<-" e.g. x <- y is equivalent to "x.<-(y)". If "x ~++<-+ y" is encountered scala will interpret it to "x.~++<-+(y)" most likely (haven't tried), they had also a precedence rule regarding user defined operators. So if we want to change python to support arbitrary operators, the operator itself probably need to be loaded by a VM instruction, and then finding that operator on the object being operated. This sounds like a lot of overhead with probably even a string comparison needed? I think in the short term this is going to be difficult to justify and I have not looked into the performance implications. But anyway in this case the importing seems not necessary, as the operator should have *NOT* being implemented in hdl.py, but is part of the object used in circuit.py. _______________________________________________ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/
