js_internal_gen.js

var assert = require("assert");

function initArray(n) {
  var res = new Array(n);
  for (var i = 0; i < n; ++i) {
    res[i] = i;
  }
  return res;
}

function gen_normal(arity) {
  if (arity === 0) {
    return "unit -> 'a0";
  } else {
    return initArray(arity + 1)
      .map(x => `'a${x}`)
      .join(" -> ");
  }
}

function gen_bs(arity) {
  if (arity === 0) {
    return "([`Arity_0], 'a0) fn";
  } else {
    return `([\`Arity_${arity} of ( ${initArray(arity)
      .map(x => `'a${x}`)
      .join(" * ")} )], 'a${arity}) fn`;
  }
}

function gen_bs_this(arity) {
  assert.notEqual(arity, 0);
  return `([\`Arity_${arity} of ( ${initArray(arity)
    .map(x => `'a${x}`)
    .join(" * ")} )], 'a${arity} ) meth_callback`;
}

function gen_bs_meth(arity) {
  if (arity === 0) {
    return `([\`Arity_0], 'a0) meth`;
  }
  return `([\`Arity_${arity} of ( ${initArray(arity)
    .map(x => `'a${x}`)
    .join(" * ")} )], 'a${arity}) meth`;
}

function generate_mk(arity) {
  return `external fn_mk${arity} : (${gen_normal(arity)}) -> (${gen_bs(
    arity
  )}) = "#fn_mk" "${arity}" `;
}

function generate_call_back_mk(arity) {
  var arity = arity + 1;
  return `external fn_method${arity} : (${gen_normal(arity)}) -> (${gen_bs_this(
    arity
  )}) = "#fn_method" "${arity}" `;
}

function generate_run(arity) {
  if (arity === 0) {
    return `external fn_run0 : (([\`Arity_0], 'a0) fn) ->  'a0  = "#fn_run" "0" `;
  }

  return `external fn_run${arity} : (${gen_bs(arity)}) -> (${gen_normal(
    arity
  )} ) = "#fn_run" "${arity}" `;
}

function generate_method_run(arity) {
  if (arity === 0) {
    return `external method_run0 : (([\`Arity_0], 'a0) meth) -> 'a0 = "#method_run" "0" `;
  }
  return `external method_run${arity} : (${gen_bs_meth(
    arity
  )}) -> (${gen_normal(arity)} ) = "#method_run" "${arity}" `;
}

var prelude = `
(* Generated by scripts/js_unsafe_gen.ml *)  
type (-'obj, +'a) meth_callback
type (-'arg, + 'result) meth
type (-'arg, + 'result) fn 
(** Js uncurried function *)
external (!)  : 'a t -> 'a = "#unsafe_downgrade"
external debugger : unit -> unit = "#debugger"
external raw_expr : string -> 'a = "#raw_expr"
external raw_stmt : string -> 'a = "#raw_stmt"
external raw_function: string ->  'a = "#raw_function"
external unsafe_downgrade : 'a t -> 'a = "#unsafe_downgrade"
`.split("\n");

function genAll(prefix) {
  var arities = initArray(10);
  var code = `${prefix} ${Array.prototype
    .concat(
      prelude,
      arities.map(generate_mk),
      arities.map(generate_call_back_mk),
      arities.map(generate_run),
      arities.map(generate_method_run)
    )
    .map(x => " " + x)
    .join("\n")}
end`;
  // console.log(arities, arities.map(x=>generate_call_back_mk(x)))
  return code;
}

var fs = require("fs");
var path = require("path");

if (require.main === module) {
  // fs.writeFileSync(path.join(__dirname, '..', 'jscomp', 'runtime', 'js_unsafe.ml'), genAll(), 'utf8')
  var jsMlFile = path.join(__dirname, "..", "jscomp", "runtime", "js.ml");
  var jsMliFile = path.join(__dirname, "..", "jscomp", "runtime", "js.mli");
  var replacement = genAll("module Internal = struct");

  var jsCode = fs.readFileSync(jsMlFile, "utf8");
  fs.writeFileSync(
    jsMlFile,
    jsCode.replace(/module Internal = struct([^])*?end/m, replacement),
    "utf8"
  );

  jsCode = fs.readFileSync(jsMliFile, "utf8");
  fs.writeFileSync(
    jsMliFile,
    jsCode.replace(
      /module Internal : sig([^])*?end/m,
      genAll("module Internal : sig")
    ),
    "utf8"
  );
}