Using Rescript/ReasonML with react

1

I created a react application using:
bsb -init ontology-editor -theme react-hooks

It creates ReasonML .re files. I renamed some of them to .res, but , .res files do not support ReasonML syntax, such as document##createElement(...). After I edited the incompatibilities, everything worked fine. Questions:

  1. I understood that Rescript was backward compatible with ReasonML (no breaking changes). Isn’t that the case?
  2. Can I freely mix .re and .res in a react project? Will the compiler recognize them without any need to alter the build files?
2
  1. ReScript has a new syntax, different from ReasonML syntax. It is not backward-compatible.
  2. Yes, you can mix .res/.re/.ml files (and their interfaces) freely within a project and the ReScript compiler will understand them all.
3

But ReScript docs says that backward compatibility for existing bucklescript codebases is one of their main goals.

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4

The ReScript compiler supports three syntaxes:

  • OCaml syntax. Equivalent to upstream OCaml syntax
  • Reason v3.6 syntax. Equivalent to upstream Reason v3.6 syntax
  • ReScript syntax. Not backward-compatible with Reason syntax

With the first two syntaxes, it provides backward-compatibility with existing BuckleScript (OCaml and Reason) codebases.

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5

I am confused about the relationship between the 3 syntaxes. I understood that the ReScript compiler would compile:

  • OCaml -> javascript
  • Reason -> OCaml -> javascript
  • ReScript -> OCaml -> javascript

If I needed, the compiler had the option to compile Reason or ReScript to OCaml. I could then
compile OCaml to native code (using another OCaml compiler). Is that the case?

6

The ReScript compiler takes those three syntaxes as input and produces JavaScript output only. It does not produce OCaml output. Targeting native OCaml is a non-goal of ReScript.