Remaining whitespace interleaving

[IwanKaramazow]

When https://github.com/facebook/reason/pull/1990 is merged, most cases where userland preservation of whitespace is absolutely a must-have, will be covered. There are other cases left, where whitespace preservation might make sense to group pieces of code together:

• jsx

  <div>
  <button onClick=(_event => self.send(Click))>
    (ReasonReact.string(message))
  </button>
  
  <button onClick=(_event => self.send(Toggle))>
    (ReasonReact.string("Toggle greeting"))
  </button>
  
  (
    self.state.show ?
      ReasonReact.string(greeting) : ReasonReact.null
  )
  </div>;

• types with record rows

  type house = {
  city: string,
  
  street: string,
  
  state: string
  };

• (poly)-variant types

  type element =
  | Fire
  
  | Water
  
  | Earth
  | Air;

• record expressions

  
  let x = {
  foo: 1,
  
  bar: 2,
  };

let make = (~greeting, _children) => { / spread the other default fields of component here and override a few / ...component,

initialState: () => {count: 0, show: true},

/ State transitions / reducer: (action, state) => switch (action) { | Click => ReasonReact.Update({...state, count: state.count + 1}) | Toggle => ReasonReact.Update({...state, show: ! state.show}) },

render: self => { let message = "You've clicked this " ++ string_of_int(self.state.count) ++ " times(s)";

self.send(Click))> (ReasonReact.string(message)) self.send(Toggle))> (ReasonReact.string("Toggle greeting")) ( self.state.show ? ReasonReact.string(greeting) : ReasonReact.null )

; }, }; ``` - objects/classes Aside from jsx most things are trivial to implement now that the intelligent whitespace interleaving algorithm™ is in place. The question is, should we? Prettier/Gofmt implements all of these cases. Are there cases that are absolutely a must? In some cases (variants, record types?), it might hinder and introduce an extra burden on the developer.

[bordoley]

The record and module type formatting cases particularly impact fields which are documented in rei files and refmt removes whitespace before the document blocks.