From 319652b052466d480769a1e6dbbb97390421f483 Mon Sep 17 00:00:00 2001
From: Sarah Gerweck <sarah.a180@gmail.com>
Date: Tue, 14 Apr 2015 23:30:20 -0700
Subject: [PATCH] Basic Scalaz applicative for ScalaFX Observables.

---
 .../org/gerweck/scalafx/util/package.scala    | 76 +++++++++++++++++++
 1 file changed, 76 insertions(+)
 create mode 100644 src/main/scala/org/gerweck/scalafx/util/package.scala

diff --git a/src/main/scala/org/gerweck/scalafx/util/package.scala b/src/main/scala/org/gerweck/scalafx/util/package.scala
new file mode 100644
index 0000000..b2d65f5
--- /dev/null
+++ b/src/main/scala/org/gerweck/scalafx/util/package.scala
@@ -0,0 +1,76 @@
+package org.gerweck.scalafx
+
+import language.implicitConversions
+
+import scalafx.beans.property._
+import scalafx.beans.value._
+import scalafx.event.subscriptions.Subscription
+import scalafx.scene.Node
+import scalafx.scene.control._
+import scalafx.scene.layout.GridPane
+import scalafx.util.StringConverter
+
+import scalaz._
+import Scalaz._
+
+/** Various implicits and global utilities for ScalaFX work.
+  *
+  * @author Sarah Gerweck <sarah@atscale.com>
+  */
+package object util {
+  type Observable[A] = ObservableValue[A, _]
+
+  implicit val observableApplicative = new Applicative[Observable] {
+    def point[A](a: => A): Observable[A] = {
+      ObjectProperty[A](a)
+    }
+
+    def ap[A, B](fa: => Observable[A])(f: => Observable[A => B]): Observable[B] = {
+      def recalculate: B = (f.value)(fa.value)
+
+      val originalValue = recalculate
+
+      val prop = ObjectProperty[B](originalValue)
+
+      var prevValue = originalValue
+
+      def changeHandler = {
+        val newVal = recalculate
+        if (prevValue != newVal) {
+          prop.value = recalculate
+        }
+      }
+
+      fa onChange changeHandler
+      f onChange changeHandler
+
+      prop
+    }
+  }
+
+  implicit class RichProperty[A](val inner: Property[A, _]) extends AnyVal {
+    def biMap[B <: AnyRef](push: A => B, pull: B => A): ObjectProperty[B] = {
+      val original = push(inner.value)
+      val op = ObjectProperty[B](original)
+      inner onChange {
+        val oldVal = op.value
+        val newVal = push(inner.value)
+        if (oldVal != newVal) {
+          op.value = push(inner.value)
+        }
+      }
+      op onChange {
+        val oldVal = inner.value
+        val newVal = pull(op.value)
+        if (oldVal != newVal) {
+          inner.value = newVal
+        }
+      }
+      op
+    }
+  }
+
+  implicit class RichGridPane(val inner: GridPane) extends AnyVal {
+    def addToRow(ri: Int, children: Node*) = inner.addRow(ri, children map {_.delegate}: _*)
+  }
+}