On Sat, Oct 29, 2016 at 12:43 PM, Nick Timkovich <prometheus235@gmail.com> wrote:
From that page: 
User-defined literals are basically normal function calls with a fancy syntax. [...] While user defined literals look very neat, they are not much more than syntactic sugar. There is not much difference between defining and calling a literal operator with "foo"_bar and doing the same with an ordinary function as bar("foo"). In theory, we could write literal operators that have side effects and do anything we want, like a normal function.

Obviously the arbitrary-function-part of that will never happen in Python (yes?)

Why not?  It seems like that would solve a lot of use-cases.  People get bringing up various new uses for prefix or suffix syntax that they want built directly into the language.  Providing a generic way to implement third-party prefixes or suffixes would save having to put all of these directly into the language.  And it opens up a lot of other potential use-cases as well.