Suppose I've got some Scala code that calls a Java library that uses _ as an identifier (and I do—it's a long story). Here's a simplified example:
public class StupidUnderscore {
public static String _() { return "Please give me a real name!"; }
}
No problem, right? Just escape it:
scala> StupidUnderscore.`_`
res0: String = Please give me a real name!
And this has always worked, until I tried to update to Scala 2.10.2 this morning:
scala> StupidUnderscore.`_`
<console>:1: error: wildcard invalid as backquoted identifier
StupidUnderscore.`_`
^
This is due to a change that showed up in 2.10.1 and fixes this issue. From the commit message:
Prohibit
_as an identifier, it can only bring badness.
Well, sure, but I don't know why that means I can't escape it—I thought that's what backquotes were for.
Am I going to have to write a Java wrapper to get this to work? Is there some other way I can refer to a Java library's _ method in Scala?
As a footnote, I've confirmed that it's possible to work around this issue without writing any new Java:
object AwfulMacroHack {
import scala.language.experimental.macros
import scala.reflect.macros.Context
def _impl(c: Context) = {
import c.universe._
c.Expr[String](
Select(Ident(newTermName("StupidUnderscore")), newTermName("_"))
)
}
def `I'm not named _!` = macro _impl
}
And then:
scala> AwfulMacroHack.`I'm not named _!`
res0: String = Please give me a real name!
I'm not sure this is any less horrible than the Java helper solution, though.
