gistfile1.txt

let nums = [1, 53, 0, 42, 3, 99, 2, 67, 4];

// Suppose we're in a function here...
let strs = nums.map(function (x) {
  switch (x) {
    case 1: return x + 'st';
    case 2: return x + 'nd';
    case 3: return x + 'rd';
    default: return x + 'th';
  }
});

// Now rewrite using proposed block lambda syntax.
// But we cannot use return!
let strs = nums.map({|x|
  if (x === 1) {
    x + 'st';
  } else if (x === 2) {
    x + 'nd';
  } else if (x === 3) {
    x + 'rd';
  } else {
    x + 'th';
  }
});

// Under maintenance a n00b adds logic for i18n to special-case 0
// and (not remembering 'return' returns from outer function) uses
// an early return -- and sees how that saves one 'else' keyword,
// converts all completion values in tail positions into 'return's
// and removes the 'else's.