1 files changed, 86 insertions, 0 deletions
diff --git a/src/repl/scala/tools/nsc/interpreter/LoopCommands.scala b/src/repl/scala/tools/nsc/interpreter/LoopCommands.scala
new file mode 100644
index 0000000000..4bba27b714
--- /dev/null
+++ b/src/repl/scala/tools/nsc/interpreter/LoopCommands.scala
@@ -0,0 +1,86 @@
+/* NSC -- new Scala compiler
+ * Copyright 2005-2013 LAMP/EPFL
+ * @author  Paul Phillips
+ */
+
+package scala.tools.nsc
+package interpreter
+
+import scala.collection.{ mutable, immutable }
+import mutable.ListBuffer
+import scala.language.implicitConversions
+
+class ProcessResult(val line: String) {
+  import scala.sys.process._
+  private val buffer = new ListBuffer[String]
+
+  val builder  = Process(line)
+  val logger   = ProcessLogger(buffer += _)
+  val exitCode = builder ! logger
+  def lines    = buffer.toList
+
+  override def toString = "`%s` (%d lines, exit %d)".format(line, buffer.size, exitCode)
+}
+
+trait LoopCommands {
+  protected def out: JPrintWriter
+
+  // So outputs can be suppressed.
+  def echoCommandMessage(msg: String): Unit = out println msg
+
+  // a single interpreter command
+  abstract class LoopCommand(val name: String, val help: String) extends (String => Result) {
+    def usage: String = ""
+    def usageMsg: String = ":" + name + (
+      if (usage == "") "" else " " + usage
+    )
+    def apply(line: String): Result
+
+    // called if no args are given
+    def showUsage(): Result = {
+      "usage is " + usageMsg
+      Result(keepRunning = true, None)
+    }
+  }
+  object LoopCommand {
+    def nullary(name: String, help: String, f: () => Result): LoopCommand =
+      new NullaryCmd(name, help, _ => f())
+
+    def cmd(name: String, usage: String, help: String, f: String => Result): LoopCommand =
+      if (usage == "") new NullaryCmd(name, help, f)
+      else new LineCmd(name, usage, help, f)
+  }
+
+  class NullaryCmd(name: String, help: String, f: String => Result) extends LoopCommand(name, help) {
+    def apply(line: String): Result = f(line)
+  }
+
+  class LineCmd(name: String, argWord: String, help: String, f: String => Result) extends LoopCommand(name, help) {
+    override def usage = argWord
+    def apply(line: String): Result = f(line)
+  }
+
+  class VarArgsCmd(name: String, argWord: String, help: String, f: List[String] => Result)
+            extends LoopCommand(name, help) {
+    override def usage = argWord
+    def apply(line: String): Result = apply(words(line))
+    def apply(args: List[String]) = f(args)
+  }
+
+  // the result of a single command
+  case class Result(keepRunning: Boolean, lineToRecord: Option[String])
+
+  object Result {
+    // the default result means "keep running, and don't record that line"
+    val default = Result(keepRunning = true, None)
+
+    // most commands do not want to micromanage the Result, but they might want
+    // to print something to the console, so we accomodate Unit and String returns.
+    implicit def resultFromUnit(x: Unit): Result = default
+    implicit def resultFromString(msg: String): Result = {
+      echoCommandMessage(msg)
+      default
+    }
+  }
+}
+