Introduce transformed vars

Author: loverdos

Diff for: src/main/scala/com/ckkloverdos/sys/SysEnv.scala

@@ -17,6 +17,7 @@
 package com.ckkloverdos.sys
 
 import com.ckkloverdos.convert.Converters
+import java.io.File
 
 /**
  * Abstraction for environment variables.
@@ -34,23 +35,31 @@ final class SysEnv(val name: String) extends SysVar[SysEnv](System.getenv(_)) {
 }
 
 object SysEnv {
-  lazy val PS1   = this("PS1")
-  lazy val PS2   = this("PS2")
+  lazy val PS1 = this("PS1")
+  lazy val PS2 = this("PS2")
 
-  lazy val SHELL   = this("SHELL")
-  lazy val TERM   = this("TERM")
+  lazy val SHELL = this("SHELL")
+  lazy val TERM = this("TERM")
 
-  lazy val PATH   = this("PATH")
-  lazy val MANPATH   = this("MANPATH")
+  lazy val PATH = this("PATH")
+
+  lazy val MANPATH = this("MANPATH")
 
   lazy val USER   = this("USER")
+
   lazy val HOME   = this("HOME")
+  lazy val HOME_FOLDER = TransformedVar.File(HOME)
 
   lazy val EDITOR = this("EDITOR")
 
   lazy val SCALA_HOME = this("SCALA_HOME")
+  lazy val SCALA_HOME_FOLDER = TransformedVar.File(SCALA_HOME)
+
   lazy val JAVA_HOME = this("JAVA_HOME")
+  lazy val JAVA_HOME_FOLDER = TransformedVar.File(JAVA_HOME)
+
   lazy val JDK_HOME = this("JDK_HOME")
+  lazy val JDK_HOME_FOLDER = TransformedVar.File(JDK_HOME)
 
   lazy val LC_CTYPE = this("LC_CTYPE")
 

Diff for: src/main/scala/com/ckkloverdos/sys/TransformedVar.scala

@@ -0,0 +1,39 @@
+/*
+ * Copyright 2011-2012 Christos KK Loverdos
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.ckkloverdos.sys
+
+import java.io.File
+
+/**
+ * A [[com.ckkloverdos.sys.SysVar]] that can be transformed to something else.
+ *
+ * @author Christos KK Loverdos <loverdos@gmail.com>
+ */
+final class TransformedVar[T <: SysVar[T], V] private(val sysVar: T, f: T ⇒ V)
+    extends Function0[V]
+       with Ordered[TransformedVar[T, V]] {
+
+  def compare(thatVar: TransformedVar[T, V]) = sysVar compare thatVar.sysVar
+
+  def apply() = f(sysVar)
+}
+
+object TransformedVar {
+  def apply[T <: SysVar[T], V](v: T)(f: T ⇒ V): TransformedVar[T, V] = new TransformedVar(v, f)
+
+  def File[T <: SysVar[T]](v: T) = TransformedVar[T, File](v)(h ⇒ new File(h.rawValue))
+}