I'm not sure what you find incomprehensible about the first example. The syntax is pretty standard. The only exotic thing is `$`, which is basically just like putting brackets around the rest of the line. Here's the first example roughly translated to Python:

  def main():
      x = 2
      [x] = ["foo"]
      y = 3
      [y] = ["bar"]
      print(x + y)

Seems about the same level of comprehensibility to me. Is there anything in particular you find difficult to understand?

The second example is expanded out and not how a person would normally write it, but if you're familiar with the basic concepts it's using, it shows why it works very clearly; think of it like assembler.