Reasonml snippets

AdvancedState.re

type stateVal = int;

type stateMod = stateVal => stateVal;

type stateModList = ref(list(stateMod));

type stateObj = {
  .
  getState: unit => stateVal,
  addModifier: stateMod => unit,
};

let updateState = List.fold_left((a, f) => f(a));

let modif = n => n + 1;

let createState = initialState => {
  let state = ref(initialState);
  let modifiers: stateModList = ref([]);
  {
    pub getState = () => updateState(state^, modifiers^);
    pub addModifier = modf => {
      modifiers := List.append(modifiers^, [modf]);
      ();
    }
  };
};

let initialState: stateVal = 1;

let state: stateObj = createState(initialState);
state#addModifier(modif);
state#addModifier(modif);
state#addModifier(modif);
Js.log(state#getState());

AdvancedStateWithTypes.re

type stateVal = int;

type stateMod('a) = 'a => 'a;

type stateModList('a) = ref(list(stateMod('a)));

type stateObj('a) = {
  .
  getState: unit => 'a,
  addModifier: stateMod('a) => unit,
  addModifiers: list(stateMod('a)) => unit
};

let updateState = List.fold_left((a, f) => f(a));

let modif = n =>
  if (n mod 2 === 0) {
    n + 20;
  } else {
    n + 3;
  };

let createState = (initialState: 'a) => {
  let state = ref(initialState);
  let modifiers: stateModList('a) = ref([]);
  {
    pub getState = () => updateState(state^, modifiers^);
    pub addModifier = modf => {
      modifiers := List.append(modifiers^, [modf]);
      ();
    };
    pub addModifiers = modfL => {
      modifiers := List.append(modifiers^, modfL);
      ();
    }
  };
};

let initialState: stateVal = 1;

let state: stateObj(stateVal) = createState(initialState);

state#addModifiers([modif, modif, modif]);

Js.log(state#getState());

State.re

type state = int;
type stateMod = (state) => state;
type stateModList = array(stateMod);

let updateState = List.fold_left((a, f) => f(a));

let modif = n => n + 1;
let modifiers = [modif, modif];

Js.log(updateState(1, modifiers));