SI-4625 Recognize App in script #5169

som-snytt · 2016-05-17T04:15:19Z

Cheap name test: if the script object extends "App",
take it for a main-bearing parent.

Note that if -Xscript is not Main, the default,
then the source is taken as a snippet and there is
no attempt to locate an existing main method.

Cheap name test: if the script object extends "App", take it for a main-bearing parent. Note that if `-Xscript` is not `Main`, the default, then the source is taken as a snippet and there is no attempt to locate an existing `main` method.

retronym · 2016-05-17T04:45:14Z

src/compiler/scala/tools/nsc/ast/parser/Parsers.scala

@@ -380,11 +380,15 @@ self =>
          case DefDef(_, nme.main, Nil, List(_), _, _)  => true
          case _                                        => false
        }
+        def isApp(t: Tree) = t match {
+          case Template(ps, _, _) => ps.exists { case Ident(x) if x.decoded == "App" => true ; case _ => false }


x == tpnme.App would be more idiomatic. That form avoids needless string creation.

or even case Ident(tpnme.App) =>

Thx, I grepped for it but missed it, trying to beat the evening rush home. Unless you mean add it to names.

Yep, I mean to add it.

retronym · 2016-05-17T04:48:17Z

LGTM, nitpick aside.

retronym · 2016-05-17T04:56:55Z

Scope creep request: Would be great if we could detect Appy modules in files with more than one definition.

% cat sandbox/test.scala && scala sandbox/test.scala
object Test {  def main(args: Array[String]) { println("!!") }}
!!

% cat sandbox/test.scala && scala sandbox/test.scala
object O
object Test {  def main(args: Array[String]) { println("!!") }}

%

som-snytt · 2016-05-17T05:31:28Z

I considered a REPLish strategy, put the entire text in a package object.

Edit: didn't do that here. But it now allows

trait X { def x = 42 }

object Main extends X with App {
  println(x)
}

Scripting knows it by name.

In an unwrapped script, where a `main` entry point is discovered in a top-level object, retain all top-level classes. Everything winds up in the default package.

It's pretty confusing when your script object becomes a local and then nothing happens. Such as when you're writing a test and it takes forever to figure out what's going on.

Fixed the warning when main module is accompanied by snippets. Minor clean-up so even I can follow what is returned.

som-snytt · 2016-05-17T21:18:56Z

I thought the scope creep was the guy with binoculars who peers in people's windows.

lrytz · 2016-05-23T14:56:12Z

src/compiler/scala/tools/nsc/ast/parser/Parsers.scala

        }
      }

-      if (mainModuleName == newTermName(ScriptRunner.defaultScriptMain))
-        searchForMain() foreach { return _ }


wow, never seen that pattern before..!

lrytz · 2016-05-23T14:56:27Z

LGTM, too

som-snytt · 2016-05-28T20:35:51Z

I just expected this to work, but I guess it hasn't been merged forward yet...

SI-4625 Recognize App in script

73ca44b

Cheap name test: if the script object extends "App", take it for a main-bearing parent. Note that if `-Xscript` is not `Main`, the default, then the source is taken as a snippet and there is no attempt to locate an existing `main` method.

scala-jenkins added this to the 2.11.9 milestone May 17, 2016

retronym reviewed May 17, 2016
View reviewed changes

scala-jenkins added the reviewed label May 17, 2016

som-snytt added 4 commits May 16, 2016 22:57

SI-4625 App is a thing

5bcefbe

Scripting knows it by name.

SI-4625 Permit arbitrary top-level in script

ee365cc

In an unwrapped script, where a `main` entry point is discovered in a top-level object, retain all top-level classes. Everything winds up in the default package.

SI-4625 Warn when discarding script object

e753135

It's pretty confusing when your script object becomes a local and then nothing happens. Such as when you're writing a test and it takes forever to figure out what's going on.

SI-4625 Warn on first non-toplevel only

7f514bb

Fixed the warning when main module is accompanied by snippets. Minor clean-up so even I can follow what is returned.

lrytz reviewed May 23, 2016
View reviewed changes

lrytz merged commit 9a703b4 into scala:2.11.x May 23, 2016

som-snytt deleted the issue/4625 branch May 31, 2016 16:56

scabug mentioned this pull request Apr 7, 2017

"scala hello_world.scala" with "object extends App" appears to never execute main scala/bug#4625

Closed

SethTisue modified the milestones: 2.11.11, 2.11.9 May 1, 2017

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SI-4625 Recognize App in script #5169

SI-4625 Recognize App in script #5169

som-snytt commented May 17, 2016

retronym May 17, 2016

retronym May 17, 2016

som-snytt May 17, 2016

retronym May 17, 2016

retronym commented May 17, 2016

retronym commented May 17, 2016

som-snytt commented May 17, 2016 •

edited

som-snytt commented May 17, 2016

lrytz May 23, 2016

lrytz commented May 23, 2016

som-snytt commented May 28, 2016

SI-4625 Recognize App in script #5169

SI-4625 Recognize App in script #5169

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som-snytt commented May 17, 2016 • edited

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som-snytt commented May 17, 2016 •

edited