TYPE_INFO _type; // Type
/// <summary>
/// this Ctor just stores the variable name
/// </summary>
/// <param name="inf"></param>
public Variable(SYMBOL_INFO inf)
{
m_name = inf.SymbolName;
}
public AssignmentStatement(SYMBOL_INFO var, Exp e)
{
variable = new Variable(var);
exp1 = e;
}
/// <summary>
///
/// </summary>
/// <param name="inf"></param>
public VariableDeclStatement(SYMBOL_INFO inf)
{
m_inf = inf;
}
/// <summary>
/// <Factor>::= <number> | ( <expr> ) | {+|-} <factor>
/// <variable> | TRUE | FALSE
/// </summary>
public Exp Factor(COMPILATION_CONTEXT ctx)
{
TOKEN l_token;
Exp RetValue = null;
if (Current_Token == TOKEN.TOK_NUMERIC)
{
RetValue = new NumericConstant(GetNumber());
Current_Token = GetToken();
}
else if (Current_Token == TOKEN.TOK_STRING)
{
RetValue = new StringLiteral(last_str);
Current_Token = GetToken();
}
else if (Current_Token == TOKEN.TOK_BOOL_FALSE ||
Current_Token == TOKEN.TOK_BOOL_TRUE)
{
RetValue = new BooleanConstant(
Current_Token == TOKEN.TOK_BOOL_TRUE ? true : false);
Current_Token = GetToken();
}
else if (Current_Token == TOKEN.TOK_OPAREN)
{
Current_Token = GetToken();
RetValue = Expr(ctx); // Recurse
if (Current_Token != TOKEN.TOK_CPAREN)
{
Console.WriteLine("Missing Closing Parenthesis\n");
throw new Exception();
}
Current_Token = GetToken();
}
else if (Current_Token == TOKEN.TOK_PLUS || Current_Token == TOKEN.TOK_SUB)
{
l_token = Current_Token;
Current_Token = GetToken();
RetValue = Factor(ctx);
if (l_token == TOKEN.TOK_PLUS)
{
RetValue = new UnaryPlus(RetValue);
}
else
{
RetValue = new UnaryMinus(RetValue);
}
}
else if (Current_Token == TOKEN.TOK_UNQUOTED_STRING)
{
///
/// Variables
///
String str = base.last_str;
SYMBOL_INFO inf = ctx.TABLE.Get(str);
if (inf == null)
{
throw new Exception("Undefined symbol");
}
GetNext();
RetValue = new Variable(inf);
}
else
{
Console.WriteLine("Illegal Token");
throw new Exception();
}
return(RetValue);
}
/// <summary>
/// The logic of this method is obvious...
/// Evaluate the Left and Right Expression...
/// Query the Type of the expressions and perform
/// appropriate action
/// </summary>
/// <param name="cont"></param>
/// <returns></returns>
public override SYMBOL_INFO Evaluate(RUNTIME_CONTEXT cont)
{
SYMBOL_INFO eval_left = ex1.Evaluate(cont);
SYMBOL_INFO eval_right = ex2.Evaluate(cont);
SYMBOL_INFO ret_val = new SYMBOL_INFO();
if (eval_left.Type == TYPE_INFO.TYPE_NUMERIC &&
eval_right.Type == TYPE_INFO.TYPE_NUMERIC)
{
ret_val.Type = TYPE_INFO.TYPE_BOOL;
ret_val.SymbolName = "";
if (m_op == RELATION_OPERATOR.TOK_EQ)
{
ret_val.bol_val = eval_left.dbl_val == eval_right.dbl_val;
}
else if (m_op == RELATION_OPERATOR.TOK_NEQ)
{
ret_val.bol_val = eval_left.dbl_val != eval_right.dbl_val;
}
else if (m_op == RELATION_OPERATOR.TOK_GT)
{
ret_val.bol_val = eval_left.dbl_val > eval_right.dbl_val;
}
else if (m_op == RELATION_OPERATOR.TOK_GTE)
{
ret_val.bol_val = eval_left.dbl_val >= eval_right.dbl_val;
}
else if (m_op == RELATION_OPERATOR.TOK_LTE)
{
ret_val.bol_val = eval_left.dbl_val <= eval_right.dbl_val;
}
else if (m_op == RELATION_OPERATOR.TOK_LT)
{
ret_val.bol_val = eval_left.dbl_val < eval_right.dbl_val;
}
return(ret_val);
}
else if (eval_left.Type == TYPE_INFO.TYPE_STRING &&
eval_right.Type == TYPE_INFO.TYPE_STRING)
{
ret_val.Type = TYPE_INFO.TYPE_BOOL;
ret_val.SymbolName = "";
if (m_op == RELATION_OPERATOR.TOK_EQ)
{
ret_val.bol_val = (String.Compare(
eval_left.str_val,
eval_right.str_val) == 0) ? true:false;
}
else if (m_op == RELATION_OPERATOR.TOK_NEQ)
{
ret_val.bol_val = String.Compare(
eval_left.str_val,
eval_right.str_val) != 0;
}
else
{
ret_val.bol_val = false;
}
return(ret_val);
}
if (eval_left.Type == TYPE_INFO.TYPE_BOOL &&
eval_right.Type == TYPE_INFO.TYPE_BOOL)
{
ret_val.Type = TYPE_INFO.TYPE_BOOL;
ret_val.SymbolName = "";
if (m_op == RELATION_OPERATOR.TOK_EQ)
{
ret_val.bol_val = eval_left.bol_val == eval_right.bol_val;
}
else if (m_op == RELATION_OPERATOR.TOK_NEQ)
{
ret_val.bol_val = eval_left.bol_val != eval_right.bol_val;
}
else
{
ret_val.bol_val = false;
}
return(ret_val);
}
return(null);
}
/// <summary>
///
/// </summary>
/// <param name="cont"></param>
/// <returns></returns>
public override SYMBOL_INFO Execute(RUNTIME_CONTEXT cont)
{
inf = (m_e1 == null) ? null : m_e1.Evaluate(cont);
return(inf);
}
