/**
* 将expression的值求出来并压到栈中
* 具体的值要看children的情况
*
*/
public override object VisitExpression([NotNull] CMMParser.ExpressionContext context)
{
// 访问子树
Object result = VisitChildren(context);
Boolean op1, op2;
if (context.ChildCount.Equals(3))
{
switch (context.GetChild(1).GetText())
{
case "&&":
codes.Add(new IntermediateCode(InstructionType.and, context.Start.Line));
// op1 = (Boolean)expStack.Pop();
// op2 = (Boolean)expStack.Pop();
// expStack.Push(op2 && op1 ? 1 : 0);
break;
case "||":
codes.Add(new IntermediateCode(InstructionType.or, context.Start.Line));
// op1 = (Boolean)expStack.Pop();
// op2 = (Boolean)expStack.Pop();
// expStack.Push(op2 || op1 ? 1 : 0);
break;
default:
break;
}
}
else if (context.ChildCount.Equals(2))
{
Double op = (Double)expStack.Pop();
expStack.Push(op == 1 ? 0 : 1);
codes.Add(new IntermediateCode(InstructionType.not, context.Start.Line));
}
return(result);
}
/// <summary>
/// Visit a parse tree produced by <see cref="CMMParser.expression"/>.
/// <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 VisitExpression([NotNull] CMMParser.ExpressionContext context)
{
return(VisitChildren(context));
}
/// <summary>
/// Enter a parse tree produced by <see cref="CMMParser.expression"/>.
/// <para>The default implementation does nothing.</para>
/// </summary>
/// <param name="context">The parse tree.</param>
public virtual void EnterExpression([NotNull] CMMParser.ExpressionContext context)
{
}
