Antlr.Runtime.BitSet.Or C# (CSharp) Method

        public BitSet Or( BitSet a )
        {
            if ( a == null )
            {
                return this;
            }
            BitSet s = (BitSet)this.Clone();
            s.OrInPlace( a );
            return s;
        }

        public virtual bool MismatchIsMissingToken(IIntStream input, BitSet follow)
        {
            if (follow == null)
            {
                // we have no information about the follow; we can only consume
                // a single token and hope for the best
                return(false);
            }
            // compute what can follow this grammar element reference
            if (follow.Member(TokenTypes.EndOfRule))
            {
                BitSet viableTokensFollowingThisRule = ComputeContextSensitiveRuleFOLLOW();
                follow = follow.Or(viableTokensFollowingThisRule);
                if (state._fsp >= 0)
                { // remove EOR if we're not the start symbol
                    follow.Remove(TokenTypes.EndOfRule);
                }
            }
            // if current token is consistent with what could come after set
            // then we know we're missing a token; error recovery is free to
            // "insert" the missing token

            //System.out.println("viable tokens="+follow.toString(getTokenNames()));
            //System.out.println("LT(1)="+((TokenStream)input).LT(1));

            // BitSet cannot handle negative numbers like -1 (EOF) so I leave EOR
            // in follow set to indicate that the fall of the start symbol is
            // in the set (EOF can follow).
            if (follow.Member(input.LA(1)) || follow.Member(TokenTypes.EndOfRule))
            {
                //System.out.println("LT(1)=="+((TokenStream)input).LT(1)+" is consistent with what follows; inserting...");
                return(true);
            }
            return(false);
        }