Exporting Union Types in Elm Syntax

[trotha01]

If we have a submodule with: type Animal = Cat | Dog

we can export Cat and Dog with: module Submodule (Animal(..)) where

and import with import Submodule exposing (Animal(..))

Can we add something that explains this on the syntax page

[halfzebra]

It is mentioned here Elm Syntax — Modules already, but I agree, it is not explicit. The best I could think of is adding a commentary about the presence of open imports for Union Types in Modules section.

[francescortiz]

I think it should be mentioned here too: https://guide.elm-lang.org/types/union_types.html

[granmoe]

Yeah, this is mysterious to a beginner and not emphasized enough in the docs (or at least not enough that I remembered it). This github issue saved me :-)

[daniel-kun]

Glad I found this github issue, because I couldn't deduct this from Elm Syntax - Modules

[zmijunkie]

Puh I am so happy to have seen this issue... Now all my Types go into a single Types.elm

[ian-moore]

This was a good 30 minutes of headache for me... glad this issue is the first result when you google it.

[fiatjaf]

For anyone looking here. Export your union type with module Module exposing (UnionType(..), otherthing, etc) and import it with import Module exposing (UnionType(..)).

[downloadpizza]

For anyone looking here. Export your union type with module Module exposing (UnionType(..), otherthing, etc) and import it with import Module exposing (UnionType(..)).

I somehow knew that importing it with (..) was possible, but I didnt think of exporting for some reason. ¯_(ツ)_/¯

[tankorsmash]

This means that you can't access Dog and Cat without explicitly exposing them right? Just import Submodule isn't enough to access them it seems like.