I need to write a parser that can extract all the text between two parentheses:
parser("left-text ( text-to-extract ) right-text") = "text-to-extract"
The text-to-extract may contain parentheses, while both left-text and right-text cannot.
I'm using Scala parser combinators, and I would like the solution to fit into it. Can you help me?
If left text is { and right text is } then your parser should be the following.
def parser: Parser[String] = "{" ~> "[^}]*".r <~ "}"
The trick is to use ~> and <~instead of ~.
Expanding on @jseteny 's answer, here is a full example, using Scala 2.13.9
import scala.util.parsing.combinator.RegexParsers
class DemoParser extends RegexParsers {
def removeBraces: Parser[String] = "{" ~> "[^}]*".r <~ "}"
}
object ExtractNested {
def main(args: Array[String]): Unit = {
val parser = new DemoParser
val result = parser.parseAll(parser.removeBraces, "{text-to-extract}")
println(result.get)
}
}