Data commit

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

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+#=
+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").
+=#
+
+using Tk
+
+w = Toplevel("Component Interaction Example")
+fr = Frame(w)
+pack(fr, expand=true, fill="both")
+
+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.
+
+incrementvalue(s) = (val = parse(Int, get_value(value)); set_value(value, string(val + 1)))
+bind(increment, "command", incrementvalue)
+
+function validate_command(path, P)
+    try
+        length(P) > 0 && parse(Float64, P)
+        tcl("expr", "TRUE")
+    catch e
+        tcl("expr", "FALSE")
+    end
+end
+function invalid_command(path, W)
+    println("Invalid value")
+    tcl(W, "delete", "@0", "end")
+end
+
+"""
+    Pressing the "random" button presents a confirmation dialog and
+    resets the field's value to a random value if the answer is "Yes".
+"""
+function randval(s)
+    out = Messagebox(w, title="Randomize input", detail="Select a new random number?")
+    if out == "ok"
+        new_value = rand(collect(1:99))
+        set_value(value, string(new_value))
+    end
+end
+bind(random, "command", randval)
+
+while true sleep(1); end