I experimented with a CoffeeScript-like Lisp in JavaScript once. It's pretty opinionated, but provides interesting syntax possibilities (infix notation, non-significant parentheses and commas for clarity, JSON-compatible syntax): https://github.com/tcr/syrup

    range = fn: [i]
      loop: [i, r = []]
        if: (i == 0) r
          continue: (i - 1), concat: (i - 1), r
    
    print: range: 5                # [0, 1, 2, 3, 4]