AwaitScript compiler concept

await-script-compiled.js

// AwaitScript sample compiled to JavaScript
var async = require('async');

function recurse(path, fn) {
  var files = [];
  fs.readdir(path, function(err, dir) {
    if (err) return fn(err);
    async.forEach(dir, function(f, fn) {
      fs.stat(f, function(err, stat) {
        if (err) return fn(err);
        if (stat.isFile()) {
          files.push(f);
          __afterIf1__();
        } else {
          recurse(path, function(err, recursiveFiles) {
            if (err) return fn(err);
            Array.prototype.push.apply(files, recursiveFiles);
            __afterIf1__();
          });
        }

        function __afterIf1__ (err) {
          if (err) return fn(err);
          __after__();
        }
      });

      function __after__(err) {
        if (err) return fn(err);
        return fn(null, files);
      }
    }, __after1__);
  });

  function __after__(err) {
    if (err) return fn(err);
    return fn(null, files);
  }
}

try {
  recurse('.', __try1__);
} catch (e) {
  __catch1__(e);
}

function __try1__ (err) {
  if (err) return __catch1__(err);
  __finally1__();
}

function __catch1__ (err) {
  console.error(e);
  __finally1__();
}

function __finally1__() {
  console.log('and done...');
  __afterTry1__();
}

function __afterTry1__(err) {
  if (err) throw err;
  console.log(files);
}

await-script.js

// the magic way that could maybe work with await
var async = require('async');  // async library is actually improved by await

async function recurse(path) {
  var files = [];
  // Awaits can only be variable assignments
  // Later versions might support anonymous awaits
  var dir = await fs.readdir(path);
  await async.forEach(dir, async function(f) {
    var stat = await fs.stat(f);
    if(stat.isFile()) {
      files.push(f);
    } else {
      var recursiveFiles = await recurse(path);
      Array.prototype.push.apply(files, recursiveFiles);
    }
  });

  return files;
}

await async try {
  await recurse('.');
} catch(e) {
  // same scope, not same tick
  console.error(e);
} finally {
  console.log('and done...');
}

console.log(files);