Add a simple interface

src/main/scala/io/atal/butterfly/Interface.scala

@@ -0,0 +1,51 @@
+package io.atal.butterfly
+
+import scala.swing._
+import scala.swing.event._
+
+/**
+ * A simple swing demo.
+ */
+object HelloWorld extends SimpleSwingApplication {
+  def top = new MainFrame {
+    title = "Hello, World!"
+
+    object editor extends Label {
+      var buffer = new Buffer("")
+      var _cursor = 0
+
+      text = buffer.toString()
+      preferredSize = new Dimension(1000,500)
+
+      listenTo(button)
+      reactions += {
+        case ButtonClicked(button) =>
+          if(input.text != "")
+          {
+            buffer.insert(input.text, _cursor)
+            _cursor += input.text.length
+            text = buffer.toString()
+            input.text = ""
+          }
+      }
+    }
+
+    object button extends Button {
+      text = "Insert"
+    }
+
+    val input = new TextField(100)
+
+    contents = new BorderPanel {
+      add(editor, BorderPanel.Position.North)
+      add(input, BorderPanel.Position.West)
+      add(button, BorderPanel.Position.East)
+      border = Swing.EmptyBorder(10, 10, 10, 10)
+
+      focusable = true
+      requestFocus
+    }
+
+  }
+}
+