update

Task/GUI-component-interaction/Julia/gui-component-interaction.julia

@@ -0,0 +1,47 @@
+using Tk
+w = Toplevel("Component Interaction Example")
+fr = Frame(w)
+pack(fr, {:expand=>true, :fill => "both"})
+## The task: For a minimal "application", write a program that
+## presents a form with three components to the user: A numeric input
+## field ("Value") and two buttons ("increment" and "random").
+
+value = Entry(fr, "")
+increment = Button(fr, "Increment")
+random = Button(fr, "Random")
+
+formlayout(value, "Value:")
+formlayout(increment, " ")
+formlayout(random, " ")
+
+set_value(value, "0") ## The field is initialized to zero.
+
+tk_bind(increment, "command") do path  ## increment its value with the "increment" button.
+  val = get_value(value) | float
+  set_value(value, string(val + 1))
+end
+
+
+function validate_command(path, P)
+    try
+        if length(P) > 0 parsefloat(P) end
+        tcl("expr", "TRUE")
+    catch e
+        tcl("expr", "FALSE")
+    end
+end
+function invalid_command(path, W)
+    println("Invalid value")
+    tcl(W, "delete", "@0", "end")
+end
+
+tk_configure(value, {:validate=>"key", :validatecommand=>validate_command, :invalidcommand=>invalid_command })
+
+## Pressing the "random" button presents a confirmation dialog, and resets the field's value to a random value if the answer is "Yes".
+tk_bind(random, "command") do path
+   out = Messagebox(w, "Randomize input", "Select a new random number?")
+   if out == "ok"
+       new_value = floor(100*rand(1))[1]
+       set_value(value, string(new_value))
+   end
+end

Task/GUI-component-interaction/Racket/gui-component-interaction.rkt

@@ -0,0 +1,25 @@
+#lang racket/gui
+
+(define frame (new frame% [label "Interaction Demo"]))
+
+(define inp
+  (new text-field% [label "Value"] [parent frame] [init-value "0"]
+       [callback
+        (λ(f ev)
+          (define v (send f get-value))
+          (unless (string->number v)
+            (send f set-value (regexp-replace* #rx"[^0-9]+" v ""))))]))
+
+(define buttons (new horizontal-pane% [parent frame]))
+(define inc-b
+  (new button% [parent buttons] [label "Increment"]
+       [callback (λ (b e) (let* ([v (string->number (send inp get-value))]
+                                 [v (number->string (add1 v))])
+                            (send inp set-value v)))]))
+(define rand-b
+  (new button% [parent buttons] [label "Random"]
+       [callback (λ (b e) (when (message-box "Confirm" "Are you sure?"
+                                             frame '(yes-no))
+                            (send inp set-value (~a (random 10000)))))]))
+
+(send frame show #t)