1 Ht DP Teachpacks
2 Ht DC Teachpacks
On this page:
control
view
connect
Version: 4.0.2

 

1.13 An Arrow GUI: arrow-gui.ss

The teachpack provides operations for creating and manipulating an arrow GUI. We recommend using the world teachpack instead.

modelT (-> button% event% true)

A modelT is a function that accepts and ignores two arguments.

(control)  symbol?

Reads out the current state of the message field.

(view s)  true

  s : (or/c string? symbol?)

Displays s in the message field.

(connect l r u d)  true

  l : modelT

  r : modelT

  u : modelT

  d : modelT

Connects four controllers with the four directions in the arrow window.

Example:

  ; Advanced

  (define (make-model dir)

     (lambda (b e)

       (begin

         (view dir)

         (printf "~a ~n" (control)))))

  

  (connect

     (make-model "left")

     (make-model "right")

     (make-model "up")

     (make-model "down"))

Now click on the four arrows. The message field contains the current direction, the print-out the prior contents of the message field.