On Thu, 29 Aug 2019 at 22:12, Andrew Barnert via Python-ideas
As I’ve said before, I believe that anything that doesn’t have a builtin type does not deserve builtin syntax. And I don’t understand why that isn’t a near-ubiquitous viewpoint. But it’s not just you; at least three people (all of whom dislike the whole concept of custom affixes) seem at least in principle open to the idea of adding builtin affixes for types that don’t exist. Which makes me think it’s almost certainly not that you’re all crazy, but that I’m missing something important. Can you explain it to me?
In my case, it's me that had missed something - namely the whole of this point. I can imagine having builtin syntax for a stdlib type (like Decimal, Fraction, or regex), but I agree that it gives the stdlib special privileges which I'm uncomfortable with. I definitely agree that built in syntax for 3rd party types is unacceptable. That quite probably contradicts some of my earlier statements - just assume I was wrong previously, I'm not going to bother going back over what I said and correcting my comments :-) I remain of the opinion that the benefits of user-defined literals would be sufficiently marginal that they wouldn't justify the cost, though. Paul