trying to write a library for interacting with the Minecraft Pi Edition API

minecraft-api.rkt

    (define-values (mc-in mc-out) (tcp-connect "192.168.1.31" 4711))
    
    (define (args->strings loa)
      (cond 
       [(empty? loa) empty]
       [else (cons (~a (first loa)) (args->strings (rest loa)))]))
        
    (define (process-args loa)
      (string-join (args->strings loa) "," 
                   #:before-first "("
                   #:after-last ") #\newline"))
        
    (define (send-command cmd-string args)
      (display (string-append cmd-string (process-args args)) mc-out)
      (flush-output mc-out))
        
    (define (get-block x y z)
      (send-command "world.getBlock" (list x y z))
      (read-line mc-in))