const double Parser::Evaluate () // get result
{
pWord_ = program_.c_str ();
type_ = NONE;
double v = CommaList (true);
if (type_ != END)
throw std::runtime_error ("Inaspettato testo al termine dell'espressione: " + std::string (pWordStart_));
return v;
}
/*!
\brief
\fn Parser::Evaluate
\return const double
*/
const double Parser::Evaluate () // get result
{
pWord_ = program_.c_str ();
type_ = NONE;
double v = CommaList (true);
if (type_ != END) {
// throw std::runtime_error ("Unexpected text at end of expression: " + std::string (pWordStart_));
}
return v;
}
/*!
\brief
\fn Parser::Primary
\param get
\return const double
*/
const double Parser::Primary (const bool get) // primary (base) tokens
{
if (get)
GetToken (); // one-token lookahead
switch (type_)
{
case NUMBER:
{
double v = value_;
GetToken (true); // get next one (one-token lookahead)
return v;
}
case NAME:
{
std::string word = word_;
GetToken (true);
if (type_ == LHPAREN)
{
// might be single-argument function (eg. abs (x) )
std::map<std::string, OneArgFunction>::const_iterator si;
si = OneArgumentFunctions.find (word);
if (si != OneArgumentFunctions.end ())
{
double v = Expression (true); // get argument
CheckToken (RHPAREN);
GetToken (true); // get next one (one-token lookahead)
return si->second (v); // evaluate function
}
// might be double-argument function (eg. roll (6, 2) )
std::map<std::string, TwoArgFunction>::const_iterator di;
di = TwoArgumentFunctions.find (word);
if (di != TwoArgumentFunctions.end ())
{
double v1 = Expression (true); // get argument 1 (not commalist)
CheckToken (COMMA);
double v2 = Expression (true); // get argument 2 (not commalist)
CheckToken (RHPAREN);
GetToken (true); // get next one (one-token lookahead)
return di->second (v1, v2); // evaluate function
}
// might be double-argument function (eg. roll (6, 2) )
std::map<std::string, ThreeArgFunction>::const_iterator ti;
ti = ThreeArgumentFunctions.find (word);
if (ti != ThreeArgumentFunctions.end ())
{
double v1 = Expression (true); // get argument 1 (not commalist)
CheckToken (COMMA);
double v2 = Expression (true); // get argument 2 (not commalist)
CheckToken (COMMA);
double v3 = Expression (true); // get argument 3 (not commalist)
CheckToken (RHPAREN);
GetToken (true); // get next one (one-token lookahead)
return ti->second (v1, v2, v3); // evaluate function
}
//throw std::runtime_error ("Function '" + word + "' not implemented.");
}
// not a function? must be a symbol in the symbol table
double & v = symbols_ [word]; // get REFERENCE to symbol table entry
// change table entry with expression? (eg. a = 22, or a = 22)
switch (type_)
{
// maybe check for NaN or Inf here (see: isinf, isnan functions)
case ASSIGN:
v = Expression (true);
break;
case ASSIGN_ADD:
v += Expression (true);
break;
case ASSIGN_SUB:
v -= Expression (true);
break;
case ASSIGN_MUL:
v *= Expression (true);
break;
case ASSIGN_DIV:
{
double d = Expression (true);
if (d == 0.0) {
//throw std::runtime_error ("Divide by zero");
}
v /= d;
break; // change table entry with expression
} // end of ASSIGN_DIV
default:
break; // do nothing for others
} // end of switch on type_
return v; // and return new value
}
case MINUS: // unary minus
return - Primary (true);
case NOT: // unary not
return (Primary (true) == 0.0) ? 1.0 : 0.0;;
case LHPAREN:
{
double v = CommaList (true); // inside parens, you could have commas
CheckToken (RHPAREN);
GetToken (true); // eat the )
return v;
}
default:
break;
//throw std::runtime_error ("Unexpected token: " + word_);
} // end of switch on type
} // end of Parser::Primary
