private Token GetToken()
{
token = new Token() { Value = "", Type = TokenType.End };
while ((index < code.Length) && char.IsWhiteSpace(code[index])) index++;
if (index < code.Length)
{
if (code[index].IsIn(delimiters))
{
int start = index++;
switch (code[start])
{
case '<':
switch (code[index])
{
case '=': index++; break;
case '>': index++; break;
}
break;
case '>':
case '=':
if (code[index] == '=')
{
index++;
}
break;
case '&':
if (code[index] == '&')
{
index++;
}
break;
case '|':
if (code[index] == '|')
{
index++;
}
break;
}
string op = code.Substring(start, index - start);
token = new Token() { Value = op, Type = TokenType.Delimiter };
}
else if (char.IsLetter(code[index]))
{
int start = index++;
while ((index < code.Length) && !code[index].IsDelim(delimiters))
{
index++;
}
string name = code.Substring(start, index - start);
TokenType type = TokenType.Variable;
if (functions.ContainsKey(name.ToUpper()))
type = TokenType.Function;
token = new Token() { Value = name, Type = type };
}
else if (char.IsDigit(code[index]))
{
int start = index++;
while ((index < code.Length) && (char.IsDigit(code[index]) || (code[index] == '.')))
{
index++;
}
token = new Token() { Value = code.Substring(start, index - start), Type = TokenType.Number };
}
}
return token;
}
private double ProcessVariable()
{
double retVal = 0;
if (token.Type == TokenType.Variable)
{
Token left = token;
int start = index;
GetToken();
if (token.Value != "=") // no es una asignacion
{
index = start; // Devuelvo a la posicion anterior
token = left;
retVal = ProcessFunction();
}
else // es una asignacion
{
GetToken();
retVal = ProcessFunction();
vars[left.Value.ToUpper()] = retVal;
}
}
else
{
retVal = ProcessFunction();
vars["X"] = retVal;
}
return retVal;
}