No, you can interleave bindings and body expressions however you like, but the catch is that you can't use destructuring bindings since they look like expressions. It works like this:
(lets) -> nil
(lets a) -> a
(lets a b . rest) ->
If `a` is ssyntax or a non-symbol, we treat it as an expression:
(do a (lets b . rest))
Otherwise, we treat it as a variable to bind:
(let a b (lets . rest))
The choice is almost forced in each case. It almost never makes sense to use an ssyntax symbol in a variable binding, and it almost never makes sense to discard the result of an expression that's just a variable name.
The implementation is here in Lathe's arc/utils.arc:
