repl.evil.scm

;; MIT License
;;
;; Copyright (c) 2023 haller33
;;
;; Permission is hereby granted, free of charge, to any person obtaining a copy
;; of this software and associated documentation files (the "Software"), to deal
;; in the Software without restriction, including without limitation the rights
;; to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
;; copies of the Software, and to permit persons to whom the Software is
;; furnished to do so, subject to the following conditions:
;;
;; The above copyright notice and this permission notice shall be included in all
;; copies or substantial portions of the Software.
;;
;; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
;; IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
;; FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
;; AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
;; LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
;; OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
;; SOFTWARE.

;; this code needs to finish the monadic or co-monadic version of the interpreter ...

;; #! /nix/store/jw2522hjypr3dv8v2sjk8gmk4jywi43w-user-environment/bin/scheme --script
;;#!/data/data/com.termux/files/usr/bin/guile -s
;;!#


;;;
;; this is my own definition of Meta Circular Evaluator.
;;

(define (inenv? exp env)
  (define (ienvaps env acc)
    (if (or (null? env) acc)
	acc
	(ienvaps (cdr env)
		 (or (eqv? (caar env) exp)
		     acc))))
  (ienvaps env #f))


(define (extraenv exp env)
  (if (eqv? (caar env) exp)
      (cadar env)
      (extraenv exp (cdr env))))


(define (insidenv frame env)
  (if (or (null? frame) (number? frame))
      env
      (insidenv (cdr frame)
		(cons (car frame)
		      env))))

(define (outsidenv frame env)
  (if (or (null? env) (number? frame))
      env
      (insidenv (cdr frame)
		(cdr env))))

(define (gc env)
  (define (exist? item lst)
    (and (not (null? lst))
	 (or (eqv? item (caar lst))
	     (exist? item (cdr lst)))))
  (define (gc-aps env acc)
    (if (null? env)
	(reverse acc)
	(gc-aps (cdr env)
		(if (not (exist? (caar env) acc))
		    (cons (car env) acc)
		    acc))))
  (gc-aps env (list (car env))))

(define (dothis exp env)
  ;;(if (atom? exp))) ;; TODO
  '())
      
  
(define (evale exp env)
  (cond ((eqv? exp 'nil)
	 '())
	((eqv? exp '#f)
	 #f)
	((eqv? exp '#t)
	 #t)
	((string? exp)
	 exp)
        ((null? exp)
	 'nil)
	((number? exp)
	 exp)
	
	((inenv? exp env)
	 (evale (extraenv exp env) env))
	((eqv? (car exp) 'do) ;; TODO
	 (dothis (list (cdr exp)) env))
	((eqv? (car exp) 'set)
	 (evale (caddr exp)
		(cons (list (cadr exp)
			    (evale (caddr exp) env))
		      env)))
	((eqv? (car exp) 'let)
	 (evale (caddr exp)
		(insidenv (cadr exp) env))
	 (evale '() (outsidenv (cadr exp) env)))
	((eqv? (car exp) 'lambda)
	 (cons '<PROCEDURE>
	       (list (caddr exp)
		     (cadr exp))))
	((eqv? (car exp) 'quot)
	 exp)
	((eqv? (car exp) 'eval)
	 (evale (cadadr exp) '()))
	((eqv? (car exp) 'write)
	 (write	(evale (cadr exp) env))
	 'nil)
	((eqv? (car exp) '==)
	 (eqv? (evale (cadr exp) env)
	       (evale (caddr exp) env)))
	((eqv? (car exp) '>)
	 (> (evale (cadr exp) env)
	    (evale (caddr exp) env)))	
	((eqv? (car exp) '<)
	 (< (evale (cadr exp) env)
	    (evale (caddr exp) env)))
	((eqv? (car exp) 'sub1)
	 (- (evale (caddr exp) env)
	    (evale (cadr exp) env)))
	((eqv? (car exp) 'some1)
	 (+ (evale (cadr exp) env)
	    (evale (caddr exp) env)))
	((eqv? (car exp) 'mult1)
	 (* (evale (cadr exp) env)
	    (evale (caddr exp) env)))
	((eqv? (car exp) 'if)
	 (if (evale (cadr exp) env)
	     (evale (caddr exp) env)))
	((eqv? (car exp) 'cons)
	 (cons (evale (cadr exp) env)
	       (evale (caddr exp) env)))
	((eqv? (car exp) '\,env)
	 (write env)
	 (evale 'nil env))
	((eqv? (car exp) '\,gc)
	 (evale '(quot gc) (gc env)))
	((eqv? (caar env) 'exit)
	 (format #t "goodbye~%"))
	((eqv? (car exp) '\,repl)
	 (write (cadar env))
	 (format #t "~% evil > ")
	 (evale '(\,repl) (cons (list 'repl (read))
				(cdr env))))
	
	((and (symbol? (car exp))
	      (symbol? (cadr exp))
	      (null? (cddr exp)))
	 (applye (list (evale (car exp) env)
		       (evale (cdr exp) env))))

	(#t
	 (write 'error)
	 (write exp)
	 (write env)
	 'nil)))


(define (applye exp env)
  (cond ((and (eqv? (caaar exp) '<PROCEDURE>)
	     (eqv? (cadar exp) '<PROCEDURE>))
	 (cons 'let
	       (list exp)))))
		 


;; debug mode
(trace evale)
(trace inenv?)
(trace extraenv)
(trace insidenv)
(trace outsidenv)
(trace gc)
(trace applye)

;;(let ((n
;;       (evale '()
;;	      '((j 88)(n 5)))))
;;  (format #t "~A~%" n))




(evale '(\,repl) '((repl Meta-Circular-Evaluator)))