Perfekt SAST. Parser

ANTLR in vollen Zügen nutzen

var f = fun a(b) { b = 10; return b; }

start: stmt* EOF;
stmt: varDecl | funDecl | expr ';' | 'return' expr ';';
varDecl: 'var' id '=' expr;
expr: id ('=' expr)? | number;
funDecl: 'fun' id '(' id* ')' '{' stmt* '}'

  override def nextToken(): Token = super.nextToken() match {
      case x: RScanToken if x.getType == foldOpen => buildFoldToken(x)
      case x: Token => x
  }

  def buildFoldToken(start: RScanToken): RScanToken = {
    val (token, list) = createFoldBlockBody(
      mutable.MutableList[RScanToken]()
        ++ List(start.asInstanceOf[RScanToken])
    )
    val result = new RScanToken(path, _tokenFactorySourcePair, foldBlock, Lexer.DEFAULT_TOKEN_CHANNEL, start.getStartIndex, token.getStopIndex)
    result.setLine(start.getLine)
    result.setCharPositionInLine(start.getCharPositionInLine)
    result.setFoldedTokens(list)
    result
  }

  private def createFoldBlockBody(list: mutable.MutableList[RScanToken]): (RScanToken, mutable.MutableList[RScanToken]) = {
    var current: RScanToken = null
    while (current == null || current.getType != Token.EOF && current.getType != foldClose) {
      current = nextToken().asInstanceOf[RScanToken]
      list += current
    }
    if (current.getType == Token.EOF)
      throw new IllegalStateException()
    (current, list)
  }

startJavaScript 
    :   HashBangLine? jsFileBody? EOF
    ;

startFoldBlock
   :   block EOF
   ;

block
    :   LBRACE stmtList? RBRACE
    |   FoldBlock 
//     ,
//     startFoldBlock
    ;

Profilerstellung

    private def printProfileInfo(parser: AbstractRScanParser, tokenStream: TokenStream): Unit = {
      // do the actual parsing
      val parseInfo = parser.getParseInfo
      val atn = parser.getATN
      for (di <- parseInfo.getDecisionInfo if di.ambiguities.size() > 0) {
        val ds = atn.decisionToState.get(di.decision)
        val ruleName = parser.ruleName(ds.ruleIndex)
        log.debug("Ambiguity in rule '" + ruleName + "' -> {}", di)
        log.debug("=========================")
        log.debug(tokenStream.getText)
        log.debug("=========================")
      }
    }

Fazit