private Expression T()
{
Expression left = F();
Expr_Binary eb = T1(left);
return(eb ?? left);
}
private Expr_Binary T1(Expression left)
{
if (Match('*'))
{
Token t = Token;
NextToken();
Expr_Binary eb = new Expr_Binary();
Expression right = F();
eb.Operator = "*";
eb.Left = left;
eb.Right = right;
Expr_Binary eb1 = T1(eb);
return(eb1 ?? eb);
}
else if (Match('/'))
{
Token t = Token;
NextToken();
Expr_Binary eb = new Expr_Binary();
Expression right = F();
eb.Operator = "/";
eb.Left = left;
eb.Right = right;
Expr_Binary eb1 = T1(eb);
return(eb1 ?? eb);
}
return(null);
}
private Expression W()
{
Expression left = T();
Expr_Binary eb = W1(left);
return(eb ?? left);
}
private Expr_Binary W1(Expression left)
{
if (Match('|'))
{
Token t = Token;
NextToken();
Expr_Binary eb = new Expr_Binary();
Expression right = T();
eb.Operator = "|";
eb.Left = left;
eb.Right = right;
Expr_Binary eb1 = W1(eb);
return(eb1 ?? eb);
}
else if (Match('&'))
{
Token t = Token;
NextToken();
Expr_Binary eb = new Expr_Binary();
Expression right = T();
eb.Operator = "&";
eb.Left = left;
eb.Right = right;
Expr_Binary eb1 = W1(eb);
return(eb1 ?? eb);
}
return(null);
}
private Expr_Binary R1(Expression left)
{
if (Match('+'))
{
Token t = Token;
NextToken();
Expr_Binary eb = new Expr_Binary();
Expression right = W();
eb.Operator = "+";
eb.Left = left;
eb.Right = right;
Expr_Binary eb1 = R1(eb);
return(eb1 ?? eb);
}
else if (Match('-'))
{
Token t = Token;
NextToken();
Expr_Binary eb = new Expr_Binary();
Expression right = W();
eb.Operator = "-";
eb.Left = left;
eb.Right = right;
Expr_Binary eb1 = R1(eb);
return(eb1 ?? eb);
}
return(null);
}
private Expression D()
{
Expression left = R();
Expr_Binary eb = D1(left);
return(eb ?? left);
}
private Expr_Binary E1(Expression left)
{
if (Match((int)TK_TYPE.TK_OP_L_AND))
{
Token t = Token;
NextToken();
Expr_Binary eb = new Expr_Binary();
Expression right = D();
eb.Operator = "&&";
eb.Left = left;
eb.Right = right;
Expr_Binary eb1 = E1(eb);
return(eb1 == null ? eb : eb1);
}
else if (Match((int)TK_TYPE.TK_OP_L_OR))
{
Token t = Token;
NextToken();
Expr_Binary eb = new Expr_Binary();
Expression right = D();
eb.Operator = "||";
eb.Left = left;
eb.Right = right;
Expr_Binary eb1 = E1(eb);
return(eb1 == null ? eb : eb1);
}
return(null);
}
private Expression E()
{
Expression left = D();
Expr_Binary eb = E1(left);
return(eb == null ? left : eb);
}
private Expression F() //operand
{
if (Match('('))
{
NextToken(); //(
Expression e = E();
Accept(')');
return(e);
}
else if (Match('-'))
{
NextToken(); //-
Expression e = T(); //lowest
Expr_Binary eb = new Expr_Binary();
eb.Operator = "*";
eb.Left = e;
Expr_Value ev = new Expr_Value();
ev.Value = "-1";
eb.Right = ev;
return(eb);
}
else if (Match((int)TK_TYPE.TK_NUMBER))
{
Expr_Value ev = new Expr_Value();
ev.Value = (string)Token.Obj;
NextToken();
return(ev);
}
else if (Match((int)TK_TYPE.TK_NAME))
{
object name = (string)Token.Obj;
NextToken(); //name
if (Match('('))
{
Expr_ValueList eas = new Expr_ValueList();
eas.ValueList = new List <Expression>();
return(CallFunction((string)name, GetActualArguments()));
}
else
{
Expr_Variable ev = new Expr_Variable();
ev.Name = (string)name;
return(ev);
}
}
return(null);
}
private Expr_Binary D1(Expression left)
{
if (Match((int)TK_TYPE.TK_OP_EQ))
{
Token t = Token;
NextToken();
Expr_Binary eb = new Expr_Binary();
Expression right = R();
eb.Operator = "==";
eb.Left = left;
eb.Right = right;
Expr_Binary eb1 = D1(eb);
return(eb1 ?? eb);
}
else if (Match((int)TK_TYPE.TK_OP_GE))
{
Token t = Token;
NextToken();
Expr_Binary eb = new Expr_Binary();
Expression right = R();
eb.Operator = ">=";
eb.Left = left;
eb.Right = right;
Expr_Binary eb1 = D1(eb);
return(eb1 ?? eb);
}
else if (Match((int)TK_TYPE.TK_OP_LE))
{
Token t = Token;
NextToken();
Expr_Binary eb = new Expr_Binary();
Expression right = R();
eb.Operator = "<=";
eb.Left = left;
eb.Right = right;
Expr_Binary eb1 = D1(eb);
return(eb1 ?? eb);
}
else if (Match('>'))
{
Token t = Token;
NextToken();
Expr_Binary eb = new Expr_Binary();
Expression right = R();
eb.Operator = ">";
eb.Left = left;
eb.Right = right;
Expr_Binary eb1 = D1(eb);
return(eb1 ?? eb);
}
else if (Match('<'))
{
Token t = Token;
NextToken();
Expr_Binary eb = new Expr_Binary();
Expression right = R();
eb.Operator = "<";
eb.Left = left;
eb.Right = right;
Expr_Binary eb1 = D1(eb);
return(eb1 ?? eb);
}
return(null);
}
