Using polymorphic records

[Brendan Tobolaski]

Apologies in advance if this has a very obvious solution.

I'm trying to annotate Cats' Either monad
<http://funcool.github.io/cats/latest/#_either>. I think I have correct
annotations for both of the records

(t/ann-record [[a :variance :covariant]]
cats.monad.either.Left
[v :- a])

(t/ann-record [[a :variance :covariant]]
cats.monad.either.Right
[v :- a])

My goal is make these usable like the build in types, i.e. I'd like to be
able to annotate the constructors like this:

(t/ann cats.monad.either.left
[a -> (cats.monad.either.Left a)])

(t/ann cats.monad.either.right
[a -> (cats.monad.either.Right a)])

Obviously I'm missing something there as all I get is an unresolved var a.
Maybe what I'm missing is a (t/All [a] ...) but I'm not really sure. Even
if that is correct, I'm not sure what I need to do to allow me to annotate
functions like this

(t/ann collect-successfull
[(t/U (cats.monad.either.Left String)
(cats.monad.either.Right (t/Vec String))) -> (t/Vec String)])

(t/ann try-read
[String -> (t/U (cats.monad.either.Left String)
(cats.monad.either.Right (t/HMap ...)))])

I'm very much a beginner at this as you can probably tell. I've spent some
time digging through the documentation and source code and I'm at a loss
for how to do this. Any help would be greatly appreciated.

[Ambrose Bonnaire-Sergeant]

As you mention, you're missing `All` binders. The `a` that is scoped in
`(All [a] ..)` is a type variable which is
picked based on the specific invocation.

eg. identity is (All [x] [x -> x]), and (identity 1) instantiates x to Num
(or some subtype of it), thus becoming [Num -> Num].

The later annotations for collect-successfull and try-read look correct to
me.

Thanks,
Ambrose

Post by Brendan Tobolaski
Apologies in advance if this has a very obvious solution.
I'm trying to annotate Cats' Either monad
<http://funcool.github.io/cats/latest/#_either>. I think I have correct
annotations for both of the records
(t/ann-record [[a :variance :covariant]]
cats.monad.either.Left
[v :- a])
(t/ann-record [[a :variance :covariant]]
cats.monad.either.Right
[v :- a])
My goal is make these usable like the build in types, i.e. I'd like to be
(t/ann cats.monad.either.left
[a -> (cats.monad.either.Left a)])
(t/ann cats.monad.either.right
[a -> (cats.monad.either.Right a)])
Obviously I'm missing something there as all I get is an unresolved var a.
Maybe what I'm missing is a (t/All [a] ...) but I'm not really sure. Even
if that is correct, I'm not sure what I need to do to allow me to annotate
functions like this
(t/ann collect-successfull
[(t/U (cats.monad.either.Left String)
(cats.monad.either.Right (t/Vec String))) -> (t/Vec String)])
(t/ann try-read
[String -> (t/U (cats.monad.either.Left String)
(cats.monad.either.Right (t/HMap ...)))])
I'm very much a beginner at this as you can probably tell. I've spent some
time digging through the documentation and source code and I'm at a loss
for how to do this. Any help would be greatly appreciated.

[Piotr Jarzemski]

Hi Brendan,

I recently created a small project with core.typed annotations for
funcool.cats:

https://github.com/kazuhiro/cats.typed

It's far from being a complete reference, however, maybe you'll find it
useful.


Regards,
Piotr Jarzemski

Post by Brendan Tobolaski
Apologies in advance if this has a very obvious solution.
I'm trying to annotate Cats' Either monad
<http://funcool.github.io/cats/latest/#_either>. I think I have correct
annotations for both of the records
(t/ann-record [[a :variance :covariant]]
cats.monad.either.Left
[v :- a])
(t/ann-record [[a :variance :covariant]]
cats.monad.either.Right
[v :- a])
My goal is make these usable like the build in types, i.e. I'd like to be
(t/ann cats.monad.either.left
[a -> (cats.monad.either.Left a)])
(t/ann cats.monad.either.right
[a -> (cats.monad.either.Right a)])
Obviously I'm missing something there as all I get is an unresolved var a.
Maybe what I'm missing is a (t/All [a] ...) but I'm not really sure. Even
if that is correct, I'm not sure what I need to do to allow me to annotate
functions like this
(t/ann collect-successfull
[(t/U (cats.monad.either.Left String)
(cats.monad.either.Right (t/Vec String))) -> (t/Vec String)])
(t/ann try-read
[String -> (t/U (cats.monad.either.Left String)
(cats.monad.either.Right (t/HMap ...)))])
I'm very much a beginner at this as you can probably tell. I've spent some
time digging through the documentation and source code and I'm at a loss
for how to do this. Any help would be greatly appreciated.