/// <summary> /// Exit a parse tree produced by <see cref="CMMParser.boolExpression"/>. /// <para>The default implementation does nothing.</para> /// </summary> /// <param name="context">The parse tree.</param> public virtual void ExitBoolExpression([NotNull] CMMParser.BoolExpressionContext context) { }
/// <summary> /// Visit a parse tree produced by <see cref="CMMParser.boolExpression"/>. /// <para> /// The default implementation returns the result of calling <see cref="AbstractParseTreeVisitor{Result}.VisitChildren(IRuleNode)"/> /// on <paramref name="context"/>. /// </para> /// </summary> /// <param name="context">The parse tree.</param> /// <return>The visitor result.</return> public virtual Result VisitBoolExpression([NotNull] CMMParser.BoolExpressionContext context) { return(VisitChildren(context)); }
/** * 判断子表达式的值并压入栈中 * * */ public override object VisitBoolExpression([NotNull] CMMParser.BoolExpressionContext context) { Object res = VisitChildren(context); Double op1, op2; if (context.ChildCount.Equals(3)) { string relationalOperator = context.GetChild(1).GetText(); IntermediateCode code = new IntermediateCode(context.Start.Line); switch (relationalOperator) { case "<=": code.type = InstructionType.le; // op1 = (Double)expStack.Pop(); // op2 = (Double)expStack.Pop(); // expStack.Push(op2 <= op1 ? 1 : 0); break; case ">=": code.type = InstructionType.ge; // op1 = (Double)expStack.Pop(); // op2 = (Double)expStack.Pop(); // expStack.Push(op2 >= op1 ? 1 : 0); break; case "==": code.type = InstructionType.eq; // op1 = (Double)expStack.Pop(); // op2 = (Double)expStack.Pop(); // expStack.Push(op2 == op1 ? 1 : 0); break; case "<": code.type = InstructionType.l; // op1 = (Double)expStack.Pop(); // op2 = (Double)expStack.Pop(); // expStack.Push(op2 < op1 ? 1 : 0); break; case ">": code.type = InstructionType.g; // op1 = (Double)expStack.Pop(); // op2 = (Double)expStack.Pop(); // expStack.Push(op2 > op1 ? 1 : 0); break; case "<>": code.type = InstructionType.ne; // op1 = (Double)expStack.Pop(); // op2 = (Double)expStack.Pop(); // expStack.Push(op2 != op1 ? 1 : 0); break; default: break; } codes.Add(code); } else { // additiveExpression的情况不用处理 直接把值压栈 } return(res); }