Overall "How will this work"

[jaredramirez]

I need to do more learning about how to generate the types in Elm and the host languages, and what approaches exist. I'm assuming we'd use ASTs. To my understanding, it is basically a parser and programmatic representation of a programming language data.

Elm ASTs:

• https://hackage.haskell.org/package/language-elm (written in Haskell)
• https://github.com/Bogdanp/elm-ast (written in Elm)

Typescript ASTs:

• https://github.com/dillonkearns/elm-typescript-interop (figure out if we can reuse this)

Reason ASTs:

• (I didn't find anything)

[jaredramirez]

Another thing to consider is what tooling already exists to parse the config file that we will use (assuming we use a config file, see https://github.com/jaredramirez/border-types/issues/2). My preference is to use a JSON config file, for this reason. Regardless, I did some quick searching to see what libraries I could find, and here are the results:

JSON parsing:

• https://hackage.haskell.org/package/aeson (Haskell)
• http://package.elm-lang.org/packages/elm-lang/core/5.1.1/Json-Decode (Elm)
• https://github.com/glennsl/bs-json (Reason)

YAML parsing:

• http://hackage.haskell.org/package/yaml (Haskell)
• (I didn't find any YAML parsers for Reason or Elm)

[jaredramirez]

Since I have decided on using Haskell for this project (see https://github.com/jaredramirez/border-types/issues/1), we will most likely use the existing elm AST and have to write our own for both Reason & Typescript.

Additionally, I will go with JSON Schema for the config file (we are generating types from a config file, see https://github.com/jaredramirez/border-types/issues/2) since the target audience is people coming from JS/TS/Reason, all of which use JSON as config files through the tooling in each ecosystem.

That being said, the first milestones of this project will be:

• Designing the schema for the config file (how to defined types period, defining associations, etc)
• Implementing the parser for the schema (should not be too challenging with (https://hackage.haskell.org/package/aeson)
• Generating Elm types from the parsed JSON (https://hackage.haskell.org/package/language-elm)
• (Down the line) Generating Reason/TS types from the parsed JSON
• (Down the line) JSON decoder/encoders for Elm & host langauges