/// <summary>
/// 若出错则返回null，否则返回result
/// </summary>
/// <param name="exprType"></param>
/// <param name="left"></param>
/// <param name="right"></param>
/// <param name="loc"></param>
/// <returns></returns>
private BinaryLogicExpr processBinaryLogicExpr(BinaryLogicExpr result, Expression left, Expression right, Location loc)
{
result.DataType = DataType.Bool;
if (result.DataType == DataType.Error)
return null;
result.FirstOp = left;
result.SecondOp = right;
result.Location = loc;
return result;
}
private BinaryCmpExpr processBinaryCmpExpr(BinaryCmpExpr result, Expression left, Expression right, Location loc)
{
if (left.DataType == DataType.Bool || left.DataType == DataType.String
|| right.DataType == DataType.Bool || right.DataType == DataType.String)
{
kernel.IssueError(ErrorType.OprandTypeError, loc);
return null;
}
else
{
result.DataType = DataType.Bool;
}
result.FirstOp = left;
result.SecondOp = right;
result.Location = loc;
return result;
}
private BinaryAlgoExpr processBinaryAlgoExpr(BinaryAlgoExpr result, Expression left, Expression right, Location loc)
{
if ((left.DataType == DataType.String || right.DataType == DataType.String) && result is AddExpr)
{
result.DataType = DataType.String;
}
else if (left.DataType == DataType.Bool || left.DataType == DataType.String
|| right.DataType == DataType.Bool || right.DataType == DataType.String)
{
kernel.IssueError(ErrorType.OprandTypeError, loc);
return null;
}
else if (left.DataType == DataType.Float || right.DataType == DataType.Float)
{
result.DataType = DataType.Float;
}
else if (left.DataType == DataType.Int && right.DataType == DataType.Int)
{
result.DataType = DataType.Int;
}
else
{
result.DataType = DataType.Unknown;
}
result.FirstOp = left;
result.SecondOp = right;
result.Location = loc;
return result;
}
private RightValue readRightValue(Expression expression)
{
if (expression is LeftValueExpr)
{
return readRightValue((expression as LeftValueExpr).LeftValue, expression.Location);
}
else if (expression is RightValueExpr)
{
return (expression as RightValueExpr).RightValue;
}
//只有上面两种情况
throw new Exception();
}
public string EvalStr(Expression expr)
{
return Eval(expr).ToString();
}
public RightValue Eval(Expression expr)
{
expr.Accept(this);
RightValue result = readRightValue(expr);
return result;
}