Fragments / Colocate data requirements

[jfrolich]

I am using graphql_ppx in a project and it is amazing. Really great work!

One issue I am trying to tackle is that with React it is very convenient to colocate the data requirements with the components. I have a few issues with fragments currently:

• If you only use variables in fragments the query won't compile saying that a variable is not used
• A bug that the bsField directive is not removed from the query (is there a way to not need that field) Fix @bsField being printed in output #76 (PR fixing this)
• Reduced type checking of fragments (couldn't explore how much the type checking is reduced due to previous bug)

How did other users tackle this. And is there a way to update this ppx to have first class fragment support.

I am a new user to OCaml/ReasonML, and browsed through this codebase and it's pretty extensive.