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/*
* sbt-boilerplate is distributed under the 2-Clause BSD license. See the LICENSE file in the root
* of the repository.
*
* Copyright (c) 2012 Johannes Rudolph
*/
package spray.boilerplate
import util.parsing.combinator.RegexParsers
import java.lang.RuntimeException
sealed trait TemplateElement {
def ~(next: TemplateElement): TemplateElement = Sequence(this, next)
}
case class Sequence(elements: TemplateElement*) extends TemplateElement {
override def ~(next: TemplateElement): TemplateElement = Sequence(elements :+ next: _*)
}
/** A literal string that shouldn't be changed */
case class LiteralString(literal: String) extends TemplateElement
/* An offset to be replaced by the current index */
case class Offset(i: Int) extends TemplateElement
/** A region in which to apply expansions */
case class Expand(inner: TemplateElement, separator: String = Expand.defaultSeparator) extends TemplateElement
object Expand {
val defaultSeparator = ", "
}
object TemplateParser extends RegexParsers {
override type Elem = Char
type Tokens = TemplateElement
override val skipWhitespace = false
def elements: Parser[TemplateElement] = rep1(element) ^^ maybeSequence
def element: Parser[TemplateElement] = offset | literalString | expand
def offset: Parser[Offset] = offsetChars ^^ (s ⇒ Offset(s.toInt))
def literalString: Parser[LiteralString] = rep1(escapedLiteralNumber | literalChar) ^^ (chs ⇒ LiteralString(chs.mkString))
def literalChar: Parser[Char] =
not("[#" | """#[^\]]*\]""".r | offsetChars) ~> elem("Any character", _ ⇒ true)
def offsetChars = "[012]".r
def escapedLiteralNumber: Parser[Char] = "##" ~> offsetChars ^^ (_.head)
def outsideTemplate: Parser[LiteralString] = """(?s).+?(?=(\[#)|(\z))""".r ^^ (LiteralString(_))
def expand: Parser[Expand] = "[#" ~> elements ~ "#" ~ separatorChars <~ "]" ^^ {
case els ~ x ~ sep ⇒ Expand(els, sep.getOrElse(Expand.defaultSeparator))
}
def outsideElements: Parser[TemplateElement] =
rep1(expand | outsideTemplate) ^^ maybeSequence
def separatorChars: Parser[Option[String]] = rep("""[^\]]""".r) ^^ (_.reduceLeftOption(_ + _))
def maybeSequence(els: Seq[TemplateElement]): TemplateElement = els match {
case one :: Nil ⇒ one
case several ⇒ Sequence(several: _*)
}
def parse(input: String): TemplateElement =
phrase(outsideElements)(new scala.util.parsing.input.CharArrayReader(input.toCharArray)) match {
case Success(res, _) ⇒ res
case x: NoSuccess ⇒ throw new RuntimeException(x.msg)
}
}
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