change rangePos() in Globals to always return a range position

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Hi all,

I have a plugin which requires range positions for tree elements, so I can locate corresponding source. While it would suffice to have a plugin-specific option (e.g. detect if a plugin requires range positions to be maintained), I'm not convinced that the code complexity is worth it (also, if accepted, the interpreter's Global could be simplified to not override this). Stripping off the start and end data from each position object seems to be a premature optimization.

I did some benchmarks of compiling scala, and it doesn't seem to make much of a difference. For the first four, I ran `ant` after `ant clean`; the last was one run of `ant strap.lib` (sorry there aren't that many runs, the entire thing takes quite a bit of time).

rangepos: 8:34, 8:23, 8:27, 8:25; strap.lib 2:15
offset position: 8:18, 8:22, 8:32, 8:29; strap.lib 2:13

Also, if anyone wants another plugin example for documentation, I could try to get authorization to post that on a public URL (mine adds a unique identifier constant to a few function calls, and emits an XML file with source locations).

regards,
Nicholas

[scabug]

Imported From: https://issues.scala-lang.org/browse/SI-2110?orig=1
Reporter: gatoatigrado
Attachments:

• rangepos.diff (created on Jun 29, 2009 10:51:23 PM UTC, 1215 bytes)

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gatoatigrado said:
proposed patch

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gatoatigrado said:
I see some changes related to this were checked in (RangePositions.scala)... if this becomes accessible for plugins at some point, please update the bug. Thanks!

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@retronym said (edited on May 12, 2012 9:17:36 AM UTC):
Yep, this is available now under -Yrangepos.

Demonstrated using macros:

  ~/code/scratch/20120512 cat t2110.scala 
import language.experimental._

object Pos {
  def impl(c: reflect.makro.Context): c.Expr[String] = c.literal(c.enclosingPosition.toString)

  def pos = macro impl
}

  ~/code/scratch/20120512 cat t2110-client.scala 
object Test extends App {
  println(Pos.pos)
}

  ~/code/scratch/20120512 scalac210 -d macro.jar t2110.scala 

  ~/code/scratch/20120512 scalac210 -Yrangepos -classpath macro.jar -d client.jar t2110-client.scala 

  ~/code/scratch/20120512 scala210 -classpath macro.jar:client.jar 
TestRangePosition(/Users/jason/code/scratch/20120512/t2110-client.scala, 35, 39, 42)