regex interpolation fails ..

gistfile1.scala

Apples-MacBook-Pro:~ debasishg$ scala
Welcome to Scala version 2.10.0 (Java HotSpot(TM) 64-Bit Server VM, Java 1.6.0_45).
Type in expressions to have them evaluated.
Type :help for more information.

scala> :paste
// Entering paste mode (ctrl-D to finish)

implicit class RContext(sc: StringContext) {
  def r = 
    new util.matching.Regex(
         sc.parts.mkString(""), 
         sc.parts.tail.map(_ => "x"): _*)
}

// Exiting paste mode, now interpreting.

defined class RContext

scala> "database:[table1,table2]" matches """(\w+)(:\[(\w+)(,(\w+))*\])?"""
res0: Boolean = true

scala> :paste
// Entering paste mode (ctrl-D to finish)

"database:[table1,table2]" match {
  case r"""(\w+)(:\[(\w+)(,(\w+))*\])?""" => true
  case _ => false
}

// Exiting paste mode, now interpreting.

res1: Boolean = false

scala> 

Here's also a blog post that gets into some of the details: http://hootenannylas.blogspot.ro/2013/02/pattern-matching-with-string.html

Okay, so your original version works just fine with non-capturing groups. That was the problem.

this works ..

scala> :paste
// Entering paste mode (ctrl-D to finish)

"database:[table1,table2]" match {
  case r"""(\w+)$d(:\[(\w+)$f(,(\w+)$x)*$y\])?$t""" => (d, f, x, y, t)
  case _ => "no match"
}

// Exiting paste mode, now interpreting.

res29: java.io.Serializable = (database,:[table1,table2],table1,,table2,table2)