check lambda form body structure more strictly about lurk-rs HOT 2 CLOSED

@porcuquine I tried implementing it the way you specified, but I find it strange that you are allowed to create a lambda with an invalid body, but you can't call it - was that your intention?

Lurk REPL welcomes you.
> (lambda () 1 2 3)
[1 iterations] => <FUNCTION () 1>
> ((lambda () 1 2 3))
Evaluation error: Function body must be only one element
> 

from lurk-rs.

Having completed the cons hashing optimizations, I now suspect we can afford to perform the destructuring earlier — so you can go ahead and change it as you suggest. We'll want to ensure that works without adding a hash to the circuit though.

from lurk-rs.