anchor.diff:     This is designed for performance critical code where you will create a lot of
      structures with the same format."
   
  -  (when (= (% (# entries) 1) 1)
  +  (when (= (% (# entries) 2) 1)
       (error "Expected an even number of arguments to const-struct" 2))
     (let* [(name (gensym))
            (body `(lambda (,name)))]
  
positive.code:   "A variation of [[struct]], which will not perform any ocercing of the KEYS in entries.
  
     Note, if you know your values at compile time, it is more performant to use [[const-struct]]."
    (when (= (% (# entries) 1) 1)
      (error "Expected an even number of arguments to struct" 2))
    (with (out (empty-struct))
      (for i 1 (# entries) 2
  
negative.code:    ```cl
     (struct :foo bar)
     ```"
    (when (= (% (# entries) 2) 1)
      (error "Expected an even number of arguments to struct" 2))
    (with (out (empty-struct))
      (for i 1 (# entries) 2
  