EJS CH8 Exercises

// Retry
function MultiplicatorUnitFailure() {}
MultiplicatorUnitFailure.prototype = Object.create(Error.prototype);

function primitiveMultiply(a, b) {
  if (Math.random() < 0.5)
    return a * b;
  else
    throw new MultiplicatorUnitFailure();
}

function reliableMultiply(a, b) {
  // Your code here.
  for (;;) {
    try {
      return primitiveMultiply(a,b);
    } catch (e) {
    	if (e instanceof MultiplicatorUnitFailure)
      		console.log("MultiplicatorUnitFailure is stupid");
    	else
      		throw e;
  	}
  }
}

console.log(reliableMultiply(8, 8));




// The Locked Box
function withBoxUnlocked(body) {
  if (box.locked) {
    var finFunc = box.lock
    box.unlock()
  }
  else
    var finFunc = box.unlock
  try {
  	body()
  } finally {
    finFunc();
  }
}

withBoxUnlocked(function() {
  box.content.push("gold piece");
});

try {
  withBoxUnlocked(function() {
    throw new Error("Pirates on the horizon! Abort!");
  });
} catch (e) {
  console.log("Error raised:", e);
}
console.log(box.locked);