First pass at cleaning up `build.sc` file syntax

1 files changed, 91 insertions, 12 deletions

diff --git a/core/src/main/scala/mill/Main.scala b/core/src/main/scala/mill/Main.scala
index 9a3ade04..87395113 100644
--- a/core/src/main/scala/mill/Main.scala
+++ b/core/src/main/scala/mill/Main.scala
@@ -1,14 +1,18 @@
 package mill
 
+import ammonite.Main
+import ammonite.main.Scripts
 import ammonite.ops._
-import ammonite.util.{Name, Res}
+import ammonite.util.{Colors, Name, Res}
 import mill.define.Task
 import mill.discover._
 import mill.eval.Evaluator
 import mill.util.OSet
 import play.api.libs.json.Format
 
-
+import scala.annotation.tailrec
+import ammonite.main.Scripts.pathScoptRead
+import ammonite.repl.Repl
 object Main {
   def apply[T: Discovered](args: Seq[String], obj: T, watch: Path => Unit) = {
     val startTime = System.currentTimeMillis()
@@ -58,21 +62,96 @@ object Main {
 
 
   def main(args: Array[String]): Unit = {
+    case class Config(home: ammonite.ops.Path = pwd/'out/'ammonite,
+                      colored: Option[Boolean] = None,
+                      help: Boolean = false,
+                      repl: Boolean = false,
+                      watch: Boolean = false)
+    import ammonite.main.Cli.Arg
+    val signature = Seq(
+      Arg[Config, Path](
+        "home", Some('h'),
+        "The home directory of the REPL; where it looks for config and caches",
+        (c, v) => c.copy(home = v)
+      ),
+      Arg[Config, Unit](
+        "help", None,
+        """Print this message""".stripMargin,
+        (c, v) => c.copy(help = true)
+      ),
+      Arg[Config, Boolean](
+        "color", None,
+        """Enable or disable colored output; by default colors are enabled
+          |in both REPL and scripts if the console is interactive, and disabled
+          |otherwise""".stripMargin,
+        (c, v) => c.copy(colored = Some(v))
+      ),
+      Arg[Config, Unit](
+        "repl", Some('r'),
+        "Open a build REPL",
+        (c, v) => c.copy(repl = true)
+      ),
+      Arg[Config, Unit](
+        "watch", Some('w'),
+        "Watch and re-run your build when it changes",
+        (c, v) => c.copy(watch = true)
+      )
+    )
+    ammonite.main.Cli.groupArgs(args.toList, signature, Config()) match{
+      case Left(err) =>
+      case Right((config, leftover)) =>
+        if (config.help){
+          val leftMargin = signature.map(ammonite.main.Cli.showArg(_).length).max + 2
+          println(ammonite.main.Cli.formatBlock(signature, leftMargin).mkString("\n"))
+        }else if (config.repl){
+          val repl = ammonite.Main(
+            predefFile = Some(pwd/"build.sc")
+          ).instantiateRepl(remoteLogger = None)
+          repl.right.get.interp.initializePredef()
+          repl.right.get.run()
+        }else {
+          val interp = ammonite.Main(
+            predefFile = Some(pwd/"build.sc")
+          ).instantiateInterpreter()
 
-    val List(buildFile, rest @_*) = args.toList
-
-    ammonite.Main().instantiateInterpreter() match{
-      case Left(problems) => pprint.log(problems)
-      case Right(interp) =>
-        val result = ammonite.main.Scripts.runScript(pwd, Path(buildFile, pwd), interp, Nil)
+          interp.right.get.initializePredef()
+          val syntheticPath = pwd/'out/"run.sc"
+          write.over(
+            syntheticPath,
+            """@main def run(args: String*) = mill.Main(args, ammonite.predef.FilePredef, interp.watch)
+              |
+              |@main def idea() = mill.scalaplugin.GenIdea(ammonite.predef.FilePredef)
+            """.stripMargin
+          )
 
-        if (!result.isSuccess) println(result)
-        else{
-          val (obj, discovered) = result.asInstanceOf[Res.Success[(Any, Discovered[Any])]].s
-          apply(rest, obj, _ => ())(discovered)
+          val res = ammonite.main.Scripts.runScript(
+            pwd,
+            syntheticPath,
+            interp.right.get,
+            Scripts.groupArgs(leftover)
+          )
 
+          handleWatchRes(res, true)
         }
     }
   }
+  def handleWatchRes[T](res: Res[T], printing: Boolean) = {
+    val success = res match {
+      case Res.Failure(msg) =>
+        println(msg)
+        false
+      case Res.Exception(ex, s) =>
+        println(
+          Repl.showException(ex, fansi.Color.Red, fansi.Attr.Reset, fansi.Color.Green)
+        )
+        false
+
+      case Res.Success(value) =>
+        if (printing && value != ()) println(pprint.PPrinter.BlackWhite(value))
+        true
 
+      case Res.Skip   => true // do nothing on success, everything's already happened
+    }
+    success
+  }
 }