IgnoreCaseなパーサコンビネータ ref: http://qiita.com/mather314/items/0535f237f007c13942dc

file0.scala

trait SampleParsers extends RegexParsers {
  /** 文字列に".i"を付けると大文字小文字を区別せずマッチさせるようにする拡張 */
  implicit class IgnoreCaseString(s: String) {
    def i: Parser[String] = ("""(?i)\Q""" + s + """\E""").r
  }

  def keyword: Parser[String] = "keyword:".i
  def value: Parser[String] = "[a-zA-Z0-9]+".r
  def parameter: Parser[(String,String)] = keyword ~ value ^^ { case k~v => (k,v) }
}

file1.scala

import org.specs2.mutable.Specification
import org.specs2.matcher.ParserMatchers

class SampleParsersSpec extends Specification with ParserMatchers {
  "keyword" should {
    "match with ignore-case" in {
      keyword must succeedOn("KEYWORD:")
      keyword must succeedOn("Keyword:")
      keyword must succeedOn("keyWord:")
    }
    "fail in other pattern" in {
      keyword must failOn("key-word:")
    }
  }
}