Following manual for .resi files, getting weird errors

1

Doesn’t this forum need a “help” section for dumb questions like mine?

Just experimenting with javascript bindings, created a file

Chance.res

type t
@new @module external make: unit => t = "Chance"
@send external getBoolLikelihood: (t, {"likelihood": int}) => bool = "bool"

let getBool = (~likelihood=50, ()) => {
  let c = make()
  c->getBoolLikelihood({"likelihood": likelihood})
}

It works, now I want a resi file so only getBool is public (yes I’ve read elsewhere that rewriting the interface to a JS module is maybe annoying) but this is just for learning.

Mousing over getBool gives me

(~?likelihood: int, unit) => bool

So I assume this is the type signature for getBool (what else could it be?), so from this, I create

Chance.resi

let getBool: (~?likelihood: int, unit) => bool

Saving it removes the “?”, confused, I save without formatting

I get this baffling error

  The implementation /Users/kevin/Development/rescript-stuff/template-one/src/lib/Chance.res
       does not match the interface src/lib/chance.cmi:
       Values do not match:
         let getBool: (~?likelihood: int, unit) => bool
       is not included in
         let getBool: (~likelihood: int, unit) => bool
       File "/Users/kevin/Development/rescript-stuff/template-one/src/lib/Chance.resi", line 2, characters 1-47:
         Expected declaration
       File "/Users/kevin/Development/rescript-stuff/template-one/src/lib/Chance.res", line 5, characters 5-12:

First thing that stands out is there is no src/lib/chance.cmi? Maybe its the “compiled” version of Chance.resi, which might be a fun fact but not really helpful.

I try again, letting the auto formatting remove the ?

       does not match the interface src/lib/chance.cmi:
       Values do not match:
         let getBool: (~?likelihood: int, unit) => bool
       is not included in
         let getBool: (~likelihood: int, unit) => bool
       File "/Users/kevin/Development/rescript-stuff/template-one/src/lib/Chance.resi", line 3, characters 1-46:
         Expected declaration
       File "/Users/kevin/Development/rescript-stuff/template-one/src/lib/Chance.res", line 5, characters 5-12:

Same exact error, even though I changed the code.

2

The type you are getting on hover is incorrect. It should actually be:

let getBool: (~likelihood: int=?, unit) => bool

Can you file an issue?

The team has said in the past that they don’t want to differentiate ‘beginner’ questions because they want to make them the norm.

3

That incorrect type is the same as from this command I found in some forum

npx bsc -i src/lib/Chance.res

maybe that’s where it comes from

‘beginner’ questions because they want to make them the norm.

challenge accepted

4

The issue with hover is fixed in rescript-vscode’s master branch. Will be available in next release

3 Likes