ES3Parser.ifStatement C# (CSharp) Method

    public ES3Parser.ifStatement_return ifStatement() // throws RecognitionException [1]
    {   
        ES3Parser.ifStatement_return retval = new ES3Parser.ifStatement_return();
        retval.Start = input.LT(1);

        object root_0 = null;

        IToken IF112 = null;
        IToken LPAREN113 = null;
        IToken RPAREN115 = null;
        IToken ELSE116 = null;
        ES3Parser.statement_return then = default(ES3Parser.statement_return);

        ES3Parser.statement_return els = default(ES3Parser.statement_return);

        ES3Parser.expression_return expression114 = default(ES3Parser.expression_return);


        object IF112_tree=null;
        object LPAREN113_tree=null;
        object RPAREN115_tree=null;
        object ELSE116_tree=null;


        var st = new IfStatement();
        retval.value =  st;

        try 
    	{
            // C:\\Users\\s.ros\\Projets\\Jint\\Jint\\ES3.g:1515:2: ( IF LPAREN expression RPAREN then= statement ({...}? ELSE els= statement )? )
            // C:\\Users\\s.ros\\Projets\\Jint\\Jint\\ES3.g:1515:4: IF LPAREN expression RPAREN then= statement ({...}? ELSE els= statement )?
            {
            	root_0 = (object)adaptor.GetNilNode();

            	IF112=(IToken)Match(input,IF,FOLLOW_IF_in_ifStatement5587); 
            		IF112_tree = (object)adaptor.Create(IF112);
            		adaptor.AddChild(root_0, IF112_tree);

            	LPAREN113=(IToken)Match(input,LPAREN,FOLLOW_LPAREN_in_ifStatement5589); 
            		LPAREN113_tree = (object)adaptor.Create(LPAREN113);
            		adaptor.AddChild(root_0, LPAREN113_tree);

            	PushFollow(FOLLOW_expression_in_ifStatement5591);
            	expression114 = expression();
            	state.followingStackPointer--;

            	adaptor.AddChild(root_0, expression114.Tree);
            	 st.Expression = ((expression114 != null) ? expression114.value : default(Expression)); 
            	RPAREN115=(IToken)Match(input,RPAREN,FOLLOW_RPAREN_in_ifStatement5595); 
            		RPAREN115_tree = (object)adaptor.Create(RPAREN115);
            		adaptor.AddChild(root_0, RPAREN115_tree);

            	PushFollow(FOLLOW_statement_in_ifStatement5599);
            	then = statement();
            	state.followingStackPointer--;

            	adaptor.AddChild(root_0, then.Tree);
            	 st.Then = ((then != null) ? then.value : default(Statement)); 
            	// C:\\Users\\s.ros\\Projets\\Jint\\Jint\\ES3.g:1515:113: ({...}? ELSE els= statement )?
            	int alt63 = 2;
            	int LA63_0 = input.LA(1);

            	if ( (LA63_0 == ELSE) )
            	{
            	    int LA63_1 = input.LA(2);

            	    if ( (( input.LA(1) == ELSE )) )
            	    {
            	        alt63 = 1;
            	    }
            	}
            	switch (alt63) 
            	{
            	    case 1 :
            	        // C:\\Users\\s.ros\\Projets\\Jint\\Jint\\ES3.g:1515:115: {...}? ELSE els= statement
            	        {
            	        	if ( !(( input.LA(1) == ELSE )) ) 
            	        	{
            	        	    throw new FailedPredicateException(input, "ifStatement", " input.LA(1) == ELSE ");
            	        	}
            	        	ELSE116=(IToken)Match(input,ELSE,FOLLOW_ELSE_in_ifStatement5607); 
            	        		ELSE116_tree = (object)adaptor.Create(ELSE116);
            	        		adaptor.AddChild(root_0, ELSE116_tree);

            	        	PushFollow(FOLLOW_statement_in_ifStatement5611);
            	        	els = statement();
            	        	state.followingStackPointer--;

            	        	adaptor.AddChild(root_0, els.Tree);
            	        	 st.Else = ((els != null) ? els.value : default(Statement)); 

            	        }
            	        break;

            	}


            }

            retval.Stop = input.LT(-1);

            	retval.Tree = (object)adaptor.RulePostProcessing(root_0);
            	adaptor.SetTokenBoundaries(retval.Tree, (IToken) retval.Start, (IToken) retval.Stop);
        }
        catch (RecognitionException re) 
    	{
            ReportError(re);
            Recover(input,re);
    	// Conversion of the second argument necessary, but harmless
    	retval.Tree = (object)adaptor.ErrorNode(input, (IToken) retval.Start, input.LT(-1), re);

        }
        finally 
    	{
        }
        return retval;
    }
    // $ANTLR end "ifStatement"