Antlr3.Tool.Grammar.DealWithTreeFilterMode C# (CSharp) Method

        protected virtual void DealWithTreeFilterMode()
        {
            object filterMode = (string)GetOption( "filter" );
            if ( type == GrammarType.TreeParser && filterMode != null && filterMode.ToString().Equals( "true" ) )
            {
                // check for conflicting options
                // filter => backtrack=true
                // filter&&output=AST => rewrite=true
                // filter&&output!=AST => error
                // any deviation from valid option set is an error
                object backtrack = (string)GetOption( "backtrack" );
                object output = GetOption( "output" );
                object rewrite = GetOption( "rewrite" );
                if ( backtrack != null && !backtrack.ToString().Equals( "true" ) )
                {
                    ErrorManager.Error( ErrorManager.MSG_CONFLICTING_OPTION_IN_TREE_FILTER,
                                       "backtrack", backtrack );
                }
                if ( output != null && !output.ToString().Equals( "AST" ) )
                {
                    ErrorManager.Error( ErrorManager.MSG_CONFLICTING_OPTION_IN_TREE_FILTER,
                                       "output", output );
                    SetOption( "output", "", null );
                }
                if ( rewrite != null && !rewrite.ToString().Equals( "true" ) )
                {
                    ErrorManager.Error( ErrorManager.MSG_CONFLICTING_OPTION_IN_TREE_FILTER,
                                       "rewrite", rewrite );
                }
                // set options properly
                SetOption( "backtrack", "true", null );
                if ( output != null && output.ToString().Equals( "AST" ) )
                {
                    SetOption( "rewrite", "true", null );
                }
                // @synpredgate set to state.backtracking==1 by code gen when filter=true
                // superClass set in template target::treeParser
            }
        }