anchor.diff:  		 exp-static
   		   #'((def vals)
   			    (& no-static
  -				   (return (err "static argument definition after ~A"
  +				   (return (err "Static argument definition after ~A."
                                   (list no-static))))
   			    (& apply-values? (not vals)
  -				   (return (err "argument ~A missing" (list num))))
  +				   (return (err "Argument ~A missing." (list num))))
   				(. (. (argdef-get-name def.) vals.)
                      (exp-main .def .vals)))
   
   		 exp-optional
   		   #'((def vals)
   				(& (argument-keyword? def.)
  -				   (return (err "Keyword ~A after &OPTIONAL" (list def.))))
  +				   (return (err "Keyword ~A after &OPTIONAL." (list def.))))
   				(= no-static '&optional)
   				(. (. (argdef-get-name def.)
   				      (argdef-get-value def vals))
  
positive.code:          err
  		   #'((msg args)
                  (? break-on-errors?
  				   (return (error (+ "; Call of function ~A: ~A~%"
                                       "; Argument definition: ~A~%"
                                       "; Given arguments: ~A~%")
                                    (symbol-name fun)
  
negative.code: 		 exp-check-too-many
             #'((def vals)
  			    (& (not def) vals
  				   (return (err "Too many arguments. Maximum is ~A, but ~A more given."
                                  (list (length argdefs) (length vals))))))
  
  		 exp-main-non-key
  