anchor.diff:         (remove-if #'null
                     (list
                      (mapcar #'struct-init-form struct-definitions)
  -                   (mapcar #'(lambda (x) (current-line x)) 
  -			   (remove-if #'null (first in-vars)))
  +                   (mapcar #'(lambda (x) (current-line (first x))) 
  +			   (remove-if #'null in-vars))
                      (mapcar #'current-line uniforms)
                      (to-top code))))))
   
  
positive.code:                 (macroexpand-and-substitute 
                   `(%make-function :main () ,@code)))))
  
  (defun write-output-string (version struct-definitions
                              code in-vars uniforms)
    
    (if (or (to-block code) (current-line code))
        (error "The following code not written to output.~%~a~%~a"
               (to-block code) (current-line code))
  
negative.code:            (*glsl-functions* (acons-many struct-functions 
                                           *glsl-functions*))
             (compiled-obj (compile-main code))
             (compiled-in-vars
  	     (let ((compiled (compile-declarations
  			      in-var-declarations :in))) 
  	       (if first-shader
  		   (add-layout-qualifiers-to-in-vars compiled)
  		   (mapcar #'list compiled))))
             (compiled-uniforms (compile-declarations 
  			       (mapcar #'list uniform-vars)
  			       :uniform)))
  