CODEWITHSUNDEEP
listschemelispracket
kblatt
kblatt

Reputation: 39

List calling with car and cdr in scheme/lisp

Currently setting cells in list notation using scheme. My question is how to make scheme(Dr Racket) list pair correctly using cons. My code accounts for the right location I want but creates a list by adding on the front. I am currently only working on the column = 1, 2, 3 or 4 aspect of this, and when row = 1 ONLY... Any help would be greatly appreciated.

(define KMMgame 0)

(define (KMMStartGame)
  ( begin
    (set! KMMgame '(  1(4 9 0 0)(99 0 0 0)(88 0 0 0)(11 0 0 1)
                       (3 8 0 0)(77 0 0 0)(66 0 0 0)(55 0 0 2)
                       (2 0 0 0)(44 0 0 0)(33 0 0 0)(22 0 0 3)
                       (1 0 0 0)(43 0 0 0)(34 0 0 0)(87 0 0 4)))
    (display "Starting Game Now!" ) (newline)
    #t))

;Passes list without the one on front (That is for my player state, irrelevant to my question)
(define ( KMMmove  KMMgame Plane Row Column Token)
        (KMMMove  (car(cdr KMMgame)) (cdr (cdr KMMgame)) Plane Row Column Token) )

;Set the cell to token.
(define (KMMMove KMMgame KMMend Plane Row Column Token)
        (if (= Row 1)
            (if (= Column 1)
                (cons (cons Token (cdr KMMgame)) KMMend)
                (cons (car KMMgame)  (KMMMove (cdr KMMgame) KMMend Plane Row (- Column 1) Token))
            ) 
;Next line accounts for rows greater than one, not working yet so please disregard. Exists to compile.
            (cons (cons (car(cdr (cdr KMMgame))) (KMMMove (car KMMgame) Plane (- Row 1) Column Token)) (cdr(cdr KMMgame))
           )
         )
)

(KMMMove KMMgame 4 1 1 999) Plane 4, Row 1, Column 1, Token to be added instead of current number 999, will print the desired output but inside an extra set of parenthesis:

((999 9 0 0)
 (99 0 0 0)
 (88 0 0 0)
 (11 0 0 1)
 (3 8 0 0)
 (77 0 0 0)
 (66 0 0 0)
 (55 0 0 2)
 (2 0 0 0)
 (44 0 0 0)
 (33 0 0 0)
 (22 0 0 3)
 (1 0 0 0)
 (43 0 0 0)
 (34 0 0 0)
 (87 0 0 4))

( KMMmove KMMgame 4 1 2 999) Plane 4, Row 1, Column 2, Token 999, gives the correct location for column but is pairing the front of the list outside. 

(4
 (999 0 0)
 (99 0 0 0)
 (88 0 0 0)
 (11 0 0 1)
 (3 8 0 0)
 (77 0 0 0)
 (66 0 0 0)
 (55 0 0 2)
 (2 0 0 0)
 (44 0 0 0)
 (33 0 0 0)
 (22 0 0 3)
 (1 0 0 0)
 (43 0 0 0)
 (34 0 0 0)
 (87 0 0 4))

Desired output for column 2:

 (4 999 0 0)
 (99 0 0 0)
 (88 0 0 0)
 (11 0 0 1)
 (3 8 0 0)
 (77 0 0 0)
 (66 0 0 0)
 (55 0 0 2)
 (2 0 0 0)
 (44 0 0 0)
 (33 0 0 0)
 (22 0 0 3)
 (1 0 0 0)
 (43 0 0 0)
 (34 0 0 0)
 (87 0 0 4)

Upvotes: 1

Views: 186

Answers (1)

KoopaM
KoopaM

Reputation: 50

To get a list like that, I'd suggest helper functions!

(define (newGameState KMMgame Row Column Plane Token)
  (if (= Plane 4)
      (steptwo KMMgame Row Column Plane Token)
      (newGameState  KMMgame (+ 4 Row) (+ Plane 1) Column Token)
   )
)
(define (steptwo KMMgame Row Column Plane Token)
        (if (= Row 1)
            (cons (stepthree (car (cdr KMMgame)) Row Column Plane Token) (cdr (cdr KMMgame)))
            (cons (car (cdr KMMgame))(steptwo (cdr KMMgame) (- Row 1) Column Plane Token))
        )
)
(define (stepthree KMMgame Row Column Plane Token)
        (if (= Column 1)
            (cons Token (cdr KMMgame))
            (cons (car KMMgame) (stepthree (cdr KMMgame) Row (- Column 1) Plane Token))
        )
)

This should give desired output!

Upvotes: 1

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