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/* __ *\
** ________ ___ / / ___ Scala API **
** / __/ __// _ | / / / _ | (c) 2006-2007, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ | **
** /____/\___/_/ |_/____/_/ | | **
** |/ **
\* */
package scala.util.parsing.syntax
/** This component provides the notion of `Token', the unit of information that is passed from lexical
* parsers in the `Lexical' component to the parsers in the `TokenParsers' component.
*
* @author Martin Odersky, Adriaan Moors
*/
trait Tokens {
/** Objects of this type are produced by a lexical parser or ``scanner'', and consumed by a parser
* {@see scala.util.parsing.combinator.syntactical.TokenParsers}.
*/
abstract class Token {
def chars: String
}
/** A class of error tokens. Error tokens are used to communicate
* errors detected during lexical analysis
*/
case class ErrorToken(msg: String) extends Token {
def chars = "*** error: "+msg
}
/** A class for end-of-file tokens */
case object EOF extends Token {
def chars = "<eof>"
}
/** This token is produced by a scanner {@see Scanner} when scanning failed. */
def errorToken(msg: String): Token = new ErrorToken(msg)
}
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