Elm Roc type comparability? · beginners

Stream: beginners

Topic: Elm Roc type comparability?

Oliver Schöning (Apr 19 2022 at 18:39):

I’m looking at Roc every now and then while working on some projects and would like to know how the possibilities are of translating types from one language to the other. Looks to me like going from Roc to Elm would be hard because of the tagged unions but taking Elm types should be easy to transpile into Roc?

Richard Feldman (Apr 19 2022 at 20:01):

actually I think numbers would be the bigger problem - closed tag unions in Roc should be straightforward to translate to/from Elm custom types, and if you had any open tag unions, you could presumably close them before translating them to Elm

Richard Feldman (Apr 19 2022 at 20:02):

but Roc has a bunch of different number types, whereas Elm has Int and Float

Richard Feldman (Apr 19 2022 at 20:04):

also Elm's Int is technically an F64 at runtime because it compiles to JavaScript and that's how JS works, so it's possible to get an Int from Elm that's Infinity or NaN

Oliver Schöning (Apr 19 2022 at 21:18):

Ah, thanks @Richard Feldman

Mario (Jun 17 2022 at 11:53):

@Oliver Schöning have been keeping an equivalencies doc here: https://fptransforms.netlify.app/transformations.html might find it helpful. Unsure if Roc is further changed since last updates by Richard tho...

Richard Feldman (Jun 17 2022 at 12:12):

tuples in Roc are now WIP https://github.com/rtfeldman/roc/issues/2935

Richard Feldman (Jun 17 2022 at 12:16):

the formatting also changed a bit, e.g.

Location :
    {
        line : I32,
        column : I32,
    }

...is now formatted as:

Location : {
    line : I32,
    column : I32,
}

Richard Feldman (Jun 17 2022 at 12:17):

there's also new syntax for Opaque Types and Abilities, but I guess there isn't a section on the equivalents of those in Elm or Haskell in there :big_smile: