+(define* (room-cmd-go room message #:key direct-obj)
+ (define exit
+ (find
+ (lambda (exit)
+ (equal? (exit-name exit) (dealias-exit-name direct-obj)))
+ (room-exits room)))
+ (define to-address (if exit
+ ;; Get the exit, but resolve it dynamically
+ ;; in case it's a special
+ (dyn-ref room (slot-ref exit 'to))
+ #f))
+ (define player (message-from message))
+ (define player-name
+ (mbody-val (<-wait player 'get-name)))
+ (cond
+ (exit
+ (call-with-values (lambda ()
+ (exit-can-traverse? exit room player))
+ (lambda* (can-traverse? #:optional player-flavortext
+ room-flavortext)
+ (cond
+ ;; The exit itself objects to moving
+ ((not can-traverse?)
+ (<- player 'tell
+ #:text (or player-flavortext
+ `("You try to go " ,direct-obj " but something "
+ "seems to block you.")))
+ (when room-flavortext
+ (room-tell-room room room-flavortext
+ #:exclude player)))
+ ;; to-address points nowhere, or exit not set.
+ ((not exit)
+ (<- player 'tell
+ #:text '((i "Yikes!") " Something weird is going on. "
+ "It seems like this exit leads nowhere, "
+ "in a programming bug kind of way. "
+ "Maybe tell an administrator?")))
+ ;; looks like we can go, so let's go!
+ (else
+ ;; Set the player's new location
+ (<-wait player 'set-loc!
+ #:loc to-address)
+ (when player-flavortext
+ (<-wait player 'tell
+ #:text player-flavortext))
+ ;; Tell everyone else the person walked away
+ (room-tell-room
+ room (or room-flavortext
+ (format #f "~a wanders ~a.\n"
+ player-name direct-obj)))
+ (<- to-address 'announce-entrance
+ #:who-entered player)
+ ;; Have the new room update the player to the new location
+ (<- to-address 'look-room
+ #:to-id player))))))
+ (else
+ (<- player 'tell
+ #:text "You don't see any way to go there.\n"))))