ambrosebs
On the topic of generating assertions from types.
22:13
ambrosebs
The biggest issue is what if types change?
22:14
ambrosebs
currently types are only collected during type checking.
22:14
ambrosebs
that's mainly to have complete control over types and dictate behaviour on when they change.
22:14
ambrosebs
obviously that control is completely lost if I use var metadata to store types, so that's out.
22:15
ambrosebs
I'm thinking something like defonce semantics for types, but with errors if types change.
22:15
ambrosebs
then check-ns or similar will clear all types collected if you want to change them.
22:16
ambrosebs
That should emulate the current approach.
aambrosebs
the cost is REPL development is a bit more awkward.
22:17
ambrosebs
but the advantage is we can generate predicates based on def-alias's without worrying about if types change.
22:17
ambrosebs
(def-alias Foo '{:a Number})
22:17
ambrosebs
(typed-predicate Foo? Foo)
22:18
ambrosebs
that's how I'd imagine predicate generation to look. That means by the time we macroexpand the second expression, we probably have to know a stable type for Foo.
