/// <summary>
/// reduce the expession
/// </summary>
/// <param name="exp"></param>
/// <returns></returns>
protected Expression calculateExp(Expression exp)
{
Expression result = null;
Expression midExp = null;
Expression expLeft = null;
Expression expRight = null;
switch (exp.m_type)
{
case Expression.VALUE:
result = exp;
break;
case Expression.TYPE_CLOSE_TO:
result = exp;
result.m_value = new BaseData(BaseData.TYPE_CLOSE_TO, 0);
break;
case Expression.TYPE_NEXT_LINE:
result = exp;
result.m_value = new BaseData(BaseData.TYPE_NEXT_LINE, 0);
break;
case Expression.EXP_SYMBOL:
VarSymbol s = m_symbolTable.ResolveVar(exp.m_symbolName);
result = new Expression(s.VALUE);
break;
case Expression.EXP_ARRAY_SYMBOL:
List <int> indexs = expressListToIndexs(exp.m_funcParams);
ArraySymbol arr = m_symbolTable.ResolveArray(exp.m_symbolName, indexs);
result = new Expression(arr.GetValue(indexs));
break;
// 内置函数
case Expression.EXP_FUNC:
List <BaseData> param = new List <BaseData>();
// convert the parameters
foreach (Expression e in exp.m_funcParams)
{
param.Add(calculateExp(e).m_value);
}
// call the function
BaseData returnVal = m_innerFunc.CallFunc(exp.m_symbolName, param);
result = new Expression(returnVal);
break;
// 用户自定义函数
case Expression.EXP_USER_FUNC:
string funcName = exp.m_symbolName;
FunSymbol func = m_symbolTable.ResolveFunc(funcName);
Expression funcParam = exp.m_funcParams[0];
BaseData paramVal = calculateExp(funcParam).m_value;
m_symbolTable.Define(new VarSymbol(CommonDef.FN_PARAM_SYMBOL, paramVal));
result = calculateExp(func.EXP);
break;
case Expression.OP_NOT:
midExp = calculateExp(exp.m_leftExp);
if (midExp.m_type == Expression.VALUE)
{
if (midExp.m_value != BaseData.ZERO)
{
result = new Expression(new BaseData(0));
}
else
{
result = new Expression(new BaseData(1));
}
}
else
{
throw new ErrorCode(ErrorCode.ERROR_CODE_12);
}
break;
case Expression.OP_NEG:
midExp = calculateExp(exp.m_leftExp);
if (midExp.m_type == Expression.VALUE)
{
result = midExp;
result.m_value.NegValue();
}
else
{
throw new ErrorCode(ErrorCode.ERROR_CODE_12);
}
break;
case Expression.EXP_INKEY:
result = new Expression(new BaseData(m_apiCall.Inkey()));
break;
// 二元运算符
case Expression.OP_ADD:
case Expression.OP_MINUS:
case Expression.OP_MUL:
case Expression.OP_DIV:
case Expression.OP_POWER:
case Expression.OP_AND:
case Expression.OP_OR:
case Expression.OP_EQUAL:
case Expression.OP_GREATER:
case Expression.OP_GREATER_EQU:
case Expression.OP_LESS:
case Expression.OP_LESS_EQ:
// check the value
expLeft = calculateExp(exp.m_leftExp);
expRight = calculateExp(exp.m_rightExp);
if (expLeft.m_type != Expression.VALUE || expRight.m_type != Expression.VALUE)
{
throw new ErrorCode(ErrorCode.ERROR_CODE_12);
}
if (exp.m_type == Expression.OP_ADD)
{
result = new Expression(expLeft.m_value + expRight.m_value);
}
else if (exp.m_type == Expression.OP_MINUS)
{
result = new Expression(expLeft.m_value - expRight.m_value);
}
else if (exp.m_type == Expression.OP_MUL)
{
result = new Expression(expLeft.m_value * expRight.m_value);
}
else if (exp.m_type == Expression.OP_DIV)
{
result = new Expression(expLeft.m_value / expRight.m_value);
}
else if (exp.m_type == Expression.OP_POWER)
{
result = new Expression(expLeft.m_value ^ expRight.m_value);
}
else if (exp.m_type == Expression.OP_AND)
{
result = new Expression(expLeft.m_value & expRight.m_value);
}
else if (exp.m_type == Expression.OP_OR)
{
result = new Expression(expLeft.m_value | expRight.m_value);
}
else if (exp.m_type == Expression.OP_EQUAL)
{
result = new Expression(expLeft.m_value == expRight.m_value ? 1 : 0);
}
else if (exp.m_type == Expression.OP_GREATER)
{
result = new Expression(new BaseData(expLeft.m_value > expRight.m_value ? 1 : 0));
}
else if (exp.m_type == Expression.OP_GREATER_EQU)
{
result = new Expression(new BaseData(expLeft.m_value >= expRight.m_value ? 1 : 0));
}
else if (exp.m_type == Expression.OP_LESS)
{
result = new Expression(new BaseData(expLeft.m_value < expRight.m_value ? 1 : 0));
}
else if (exp.m_type == Expression.OP_LESS_EQ)
{
result = new Expression(new BaseData(expLeft.m_value <= expRight.m_value ? 1 : 0));
}
break;
default:
throw new ErrorCode(ErrorCode.ERROR_CODE_02);
}
return(result);
}
