/*
* 读指令
*/
public override object VisitReadStatement([NotNull] CMMParser.ReadStatementContext context)
{
CMMParser.LeftValueContext[] leftValueContexts = context.leftValue();
foreach (CMMParser.LeftValueContext leftValueContext in leftValueContexts)
{
string variableName = leftValueContext.GetChild(0).GetText();
Boolean result = curLocalVariablesTable.TryGetValue(variableName, out int address);
if (!result)
{
throw new VariableNotFountException(variableName, context);
}
if (leftValueContext.ChildCount == 1)
{
codes.Add(new IntermediateCode(InstructionType.read, context.Start.Line));
codes.Add(new IntermediateCode(address, InstructionType.pop, context.Start.Line));
}
else
{
codes.Add(new IntermediateCode(InstructionType.read, context.Start.Line));
// 计算数组地址
codes.Add(new IntermediateCode(address, InstructionType.push, context.Start.Line));
Visit(context.GetChild(2));
codes.Add(new IntermediateCode(InstructionType.add, context.Start.Line));
// 保存地址的值
codes.Add(new IntermediateCode(curLocalVariablesTableLength, InstructionType.pop, context.Start.Line));
// 指针寻址赋值
codes.Add(new IntermediateCode("(" + curLocalVariablesTableLength.ToString() + ")", InstructionType.pop, context.Start.Line));
}
}
return(null);
}
/// <summary>
/// Visit a parse tree produced by <see cref="CMMParser.readStatement"/>.
/// <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 VisitReadStatement([NotNull] CMMParser.ReadStatementContext context)
{
return(VisitChildren(context));
}
/// <summary>
/// Exit a parse tree produced by <see cref="CMMParser.readStatement"/>.
/// <para>The default implementation does nothing.</para>
/// </summary>
/// <param name="context">The parse tree.</param>
public virtual void ExitReadStatement([NotNull] CMMParser.ReadStatementContext context)
{
}
