;;; proc.ss

(load "/u/c311/ss/let.ss")

(define <proc-language> ; EOPL Figure 5.4.1
  (class ()
    (base <let-language>)
    (base-inst-vars <extended-environment> test-clauses)
    (base-methods (base-parse parse))
    (base-init)
    (inst-vars
      (define <closure>
	(class (formals body env)
	  (base <procedure>)
	  (inst-vars formals body env)
	  (methods
	    (define apply
	      (method (args)
		(eval body (<extended-environment> env formals args)))))))
      (define <proc>
	(class (formals body)
	  (base <syntax>)
	  (base-methods unparse)
	  (inst-vars formals body)
	  (methods
	    (define eval
	      (method (env)
		(<closure> formals body env)))
	    (define unparse
	      (method ()
		(list 'proc formals (unparse body)))))))
      (set! test-clauses
	(append
	  '((((proc (x) x) 3) 3)
	    (((proc (x y) (+ x y)) 1 2) 3)
	    ((((proc (x) (proc (y) (+ x y))) 3) 4) 7))
	  test-clauses)))
    (methods
      (define name
	(method () 'proc))
      (define parse
	(method (datum)
	  (form-case datum
	    (proc (formals body)
	      (<proc> formals (parse this body)))
	    (else (base-parse this datum))))))))