#!/afs/cats.ucsc.edu/courses/cmps112-wm/usr/racket/bin/mzscheme -qr
;; $Id: sbi.scm,v 1.3 2016-09-23 18:23:20-07 - - $
;;
;; NAME
;;    sbi.scm - silly basic interpreter
;;
;; SYNOPSIS
;;    sbi.scm filename.sbir
;;
;; DESCRIPTION
;;    The file mentioned in argv[1] is read and assumed to be an SBIR
;;    program, which is the executed.  Currently it is only printed.
;;


;; here we create our tables
(define *label-table* (make-hash))
(define *variable-table* (make-hash))
(define *function-table* (make-hash))


;; here we fill the function table with the prelim. functions
;; I think we write somethin like this to uses functions
;; (printf "2 ^ 16 = ~s~n" ((symbol-get '^) 2.0 16.0))

;; I changed symbol-get and symbol-put to require the table
;; that their grabbing from so that way we could use them for
;; other hash tables :-)
(define (symbol-get table key)
        (hash-ref table key))
(define (symbol-put! table key value)
        (printf "~n~nputting ~s in table:~s  as ~s~n~n" key table value)
        (hash-set! table key value))

(for-each
    (lambda (pair)
            (symbol-put! *function-table* (car pair) (cadr pair)))
    `(

        (log10_2 0.301029995663981195213738894724493026768189881)
        (sqrt_2  1.414213562373095048801688724209698078569671875)
        (div     ,(lambda (x y) (floor (/ x y))))
        (log10   ,(lambda (x) (/ (log x) (log 10.0))))
        (mod     ,(lambda (x y) (- x (* (div x y) y))))
        (quot    ,(lambda (x y) (truncate (/ x y))))
        (rem     ,(lambda (x y) (- x (* (quot x y) y))))
        (+       ,+)
        (*       ,*)
        (-       ,-)
        (/       ,/)
        (^       ,expt)
        (ceil    ,ceiling)
        (exp     ,exp)
        (floor   ,floor)
        (log     ,log)
        (sqrt    ,sqrt)
        (sin     ,sin)
        (cos     ,cos)
        (tan     ,tan)
        (atan    ,atan)
        (let     , (lambda x (interpret-let x)))
        (print   , (lambda x (displayln x))) ;;(map (lambda (x) displayln x (y))));;                  (displayln (car x))))

     ))
;; now we fill the variable table with the prelim values pi & e
(for-each
    (lambda (pair)
            (symbol-put! *variable-table* (car pair) (cadr pair)))
    `(

        (e       2.718281828459045235360287471352662497757247093)
        (pi      3.141592653589793238462643383279502884197169399)
))


;; here I create 'methods'
;; label table
(define (get-label line-list)
    (if (null? (cdr line-list))
        null
        (if (null? (cadr line-list))
            null
            (if (symbol? (cadr line-list))
                (hash-set! *label-table* (cadr line-list) (cddr line-list))
                null))))

(define (get-stmt line-list)
    (if (null? (cdr line-list))
        null
        (if (null? (cadr line-list))
            null
            (if (not (symbol? (cadr line-list)))
                (cadr line-list)
                null))))


;; goal find first smt on a line and evaluate the statement
(define (get-stmt line)
     (if (null? (cdr line))
        null
        (if (null? (cadr line))
            null
            (if (symbol? (cadr line)) ;; if a label
                (cddr line);; return the next item
                (cadr line))))) ;; otherwise return stmt vthis may be wrong

;; this method runs a single line of code
;; for this we first check if there is a label
;; or if there is a stmt
;; then we get the stmt and check the car of it
;; see if the cadr is equal to one of the six  key words
;; depending on which one we perform at action with the items
;; after the car
;; then look for next item on that list of line

;; if the cdr is null
;; - skip
;; now check if there is a label or no label



;; (begin (printf"statement not null "))  <---trash stmnt]
;; printf("The interpreter line was not null")))
;;(define (interpret-line line)
;;    (if (null? (  get-stmt line))
;;        null))

    ;;;;;;
;;        ())
;;    ( if (eq? (car (get-stmt line)) ("print"))
;;          (printf "~s~n" cadr (get-stmt line))
;;          ()) ;; do nothing, IDK IF U CAN DO THIS
;;    ( if) ;;  more if statements follow



(define *stderr* (current-error-port))

(define *run-file*
    (let-values
        (((dirpath basepath root?)
            (split-path (find-system-path 'run-file))))
        (path->string basepath))
)

(define (die list)
    (for-each (lambda (item) (display item *stderr*)) list)
    (newline *stderr*)
    (exit 1)
)

(define (usage-exit)
    (die `("Usage: " ,*run-file* " filename"))
)

(define (readlist-from-inputfile filename)
    (let ((inputfile (open-input-file filename)))
         (if (not (input-port? inputfile))
             (die `(,*run-file* ": " ,filename ": open failed"))
             (let ((program (read inputfile)))
                  (close-input-port inputfile)
                         program))))

(define (write-program-by-line filename program)
    (printf "==================================================~n")
    (printf "~a: ~s~n" *run-file* filename)
    (printf "==================================================~n")
    (printf "(~n")
    ;; this map function returns a list named 'program' which is the result of the procedure
    ;; (map (lambda (line) (printf "~s~n" line)) program) ;; this is where we print out each line
    ;; first pass grabbing labels
    ;; second pass interpret
    ;;(map (lambda (line) (get-stmt line)) program)
    ;;(map (lambda (line) ()))
    ;; (printf ")~n Output: ~n")

    ;;(map (lambda (line) (get-label line)) program)
    (eval-expr program)
 )


;; implementing LET statement
(define (interpret-let expr)
   (printf "let-interpretting.. ~s ~n" expr)
   (printf "car is ~s ~n" (car expr))
   (printf "cdr is ~s ~n" (cdr expr))
   ;;(printf (pair? expr))
   (cond ((null? expr) #f)
       ((symbol? (car expr)) ;; if we see a variable, put in var table
           ;; (begin
               ;;  (print"symbol -interp let ~n")
                 (symbol-put! *variable-table* (car expr)  (eval-expr (cadr expr))));;))
        ((pair? (car expr)) ;; if we see a list recur into that expr and also recur on whatever is after
            (begin
                 (print "pair interp-let ~n")
                 (interpret-let (car expr))
                 (interpret-let (cdr expr))))
        ((number? (car expr));; if we see a num this is an error
            (printf "error, a number may not be the head of a list"))
        ((hash-has-key? *function-table* (car expr)) ;; if we see somesort of operation do it
             (eval-expr expr))
        (else #f))
)

;; implementing DIM statement
(define (interpret-dim expr)
    ;; what do we put here? do we make a vector? a list?
    (symbol-put *variable-table* (car expr) )
)

(define (eval-expr expr)
   (printf "evaluating...~s ~n" expr)
   (cond ((number? expr) expr)
         ((symbol? expr)
            (if (hash-has-key? *variable-table* expr)
                (symbol-get *variable-table* expr)
                (hash-ref *function-table* expr #f)))
         ((pair? expr)
                (if (eq? (car expr) `let)
                    (interpret-let (cdr expr))
                    (if (hash-has-key? *function-table* (car expr))
                        (apply (symbol-get *function-table* (car expr)) (map eval-expr (cdr expr)))                                                        ;;(apply (hash-ref *function-table* (car expr)))
                        (map eval-expr (cdr expr)))))
         ((null? expr) #f)
         (else  expr))

)

(define (main arglist)
    (if (or (null? arglist) (not (null? (cdr arglist))))
        (usage-exit)
        (let* ((sbprogfile (car arglist))
               (program (readlist-from-inputfile sbprogfile)))
              (write-program-by-line sbprogfile program))))

(main (vector->list (current-command-line-arguments)))