[jasbrg]

> Why is the second set of parens necessary?

it distinguishes the bindings from the body.

strictly speaking there's a more direct translation using `setq` which is more analogous to variable assignment in C/Python than the `let` binding, but `let` is idiomatic in lisps and closures in C/Python aren't really distinguished from functions.

[eadmund]

You’re right!

    (let (bar-x quux-y)
      (setq bar-x (bar-x)
            quux-y (quux y))
      (foo bar-x quux-y z))

I just wouldn’t normally write it that way.