LISTTERM = LIST | VAR (value is LIST) | FUNCALL (return LIST)
XXXTERM = TERM
-;; Here after, when an argument written as TERM, it is given to a
+;; Here after, when an argument is written as TERM, it is given to a
;; function without being evaluted. Otherwise, an evaluated term is
;; given. "the value is NUM" means "the value is
;; <integer>NUM</integer>".