Refactor Driver

 - Make parts more reusable
 - Introduce hook "sourcesRequired" that controls whether
   no sources on the command line give a help message.

1 files changed, 24 insertions, 17 deletions

diff --git a/src/dotty/tools/dotc/Driver.scala b/src/dotty/tools/dotc/Driver.scala
index f5e41cbef..7e9d4a5e4 100644
--- a/src/dotty/tools/dotc/Driver.scala
+++ b/src/dotty/tools/dotc/Driver.scala
@@ -8,33 +8,40 @@ import scala.util.control.NonFatal
 
 abstract class Driver extends DotClass {
 
-  val prompt = "\ndotc>"
+  val prompt = "\ndotc> "
 
   protected def newCompiler(): Compiler
 
   protected def emptyReporter: Reporter = new StoreReporter
 
-  protected def doCompile(compiler: Compiler, fileNames: List[String], reporter: Option[Reporter] = None)
-      (implicit ctx: Context): Reporter =
-    if (fileNames.nonEmpty) {
-      val run = compiler.newRun(ctx, reporter)
-      run.compile(fileNames)
-      run.printSummary()
-    } else emptyReporter
+  protected def doCompile(compiler: Compiler, fileNames: List[String])(implicit ctx: Context): Reporter =
+    if (fileNames.nonEmpty)
+      try {
+        val run = compiler.newRun
+        run.compile(fileNames)
+        run.printSummary()
+      }
+      catch {
+        case ex: FatalError  =>
+          ctx.error(ex.getMessage) // signals that we should fail compilation.
+          ctx.typerState.reporter
+      }
+    else emptyReporter
 
   protected def initCtx = (new ContextBase).initialCtx
 
-  def process(args: Array[String], rootCtx: Context, reporter: Option[Reporter] = None): Reporter = {
+  protected def sourcesRequired = true
+
+  def setup(args: Array[String], rootCtx: Context): (List[String], Context) = {
     val summary = CompilerCommand.distill(args)(rootCtx)
     implicit val ctx: Context = initCtx.fresh.setSettings(summary.sstate)
-    val fileNames = CompilerCommand.checkUsage(summary)
-    try {
-      doCompile(newCompiler(), fileNames, reporter)
-    } catch {
-      case ex: FatalError  =>
-        ctx.error(ex.getMessage) // signals that we should fail compilation.
-        ctx.typerState.reporter
-    }
+    val fileNames = CompilerCommand.checkUsage(summary, sourcesRequired)
+    (fileNames, ctx)
+  }
+
+  def process(args: Array[String], rootCtx: Context): Reporter = {
+    val (fileNames, ctx) = setup(args, rootCtx)
+    doCompile(newCompiler(), fileNames)(ctx)
   }
 
   def main(args: Array[String]): Unit =