;;; -*- Mode: Lisp; Syntax: Common-Lisp; -*- File: language/grammars.lisp

;;;; Definition of Lexicons and Grammars

(define-language E-0
  ;; Figure 22.5 and 22.6 [p 665]
  :lexicon
  ("Noun      => stench | breeze | glitter | nothing | wumpus | pit | pits
	      | gold | north | south | east | west"
   "Verb      => is | see | smell | shoot | feel | stinks | go | grab 
	      | carry | kill | turn"
   "Adjective => right | left | east | south | back | smelly"
   "Adverb    => here | there | nearby | ahead | right | left 
	      | east | south | back"
   "Pronoun   => me | you | I | it"
   "Name      => John | Mary | Boston | Aristotle"
   "Article   => the | a | an"
   "Preposition => to | in | on | near"
   "Conjunction => and | or | but"
   "Digit       => 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9"
   "That        => that")
  :grammar
  ("S  => NP VP | S Conjunction S"
   "NP => Pronoun | Noun | Article Noun | Digit Digit | NP PP | NP RelClause"
   "VP => Verb | VP NP | VP Adjective | VP PP | VP Adverb"
   "PP => Preposition NP"
   "RelClause => That VP"))

(define-language Arithmetic
  ;; Figure 22.13 [p 673]
  :grammar
  ("Exp(sem) => Exp(sem1) + Operator(op) + Exp(sem2) + {sem = Apply(op, sem1,sem2)}"
   ((Exp sem) => (Exp sem1) (Operator op) (Exp sem2)