object evalNode(Symbol node)
{
object left;
object right;
//double x;
switch (node.type)
{
case TokenType.number:
case TokenType.litstring:
return(node.value);
case TokenType.mod:
left = evalNode(node.left);
right = evalNode(node.right);
if (left is string || right is string)
{
string errorString = string.Format("Incompatible types at line {0} position {1}.", node.stRow, node.stCol);
throw new Exception(errorString);
}
//x = Convert.ToDouble(right);
//if (x == 0)
//{
// string errorString = string.Format("Division by zero at line {0} position {1}.", node.right.stRow, node.right.stCol);
// throw new Exception(errorString);
//}
//return left % right;
return(Convert.ToDouble(left) % Convert.ToDouble(right));
case TokenType.mul:
left = evalNode(node.left);
right = evalNode(node.right);
if (left is string || right is string)
{
string errorString = string.Format("Incompatible types at line {0} position {1}.", node.stRow, node.stCol);
throw new Exception(errorString);
}
return(Convert.ToDouble(left) * Convert.ToDouble(right));
case TokenType.plus:
left = evalNode(node.left);
right = evalNode(node.right);
if (left is string || right is string)
{
return(left.ToString() + right.ToString());
}
return(Convert.ToDouble(left) + Convert.ToDouble(right));
case TokenType.minus:
right = evalNode(node.right);
if (right is string)
{
string errorString = string.Format("Incompatible types at line {0} position {1}.", node.stRow, node.stCol);
throw new Exception(errorString);
}
if (node.left == null)
{
return(-Convert.ToDouble(right));
}
left = evalNode(node.left);
if (left is string)
{
string errorString = string.Format("Incompatible types at line {0} position {1}.", node.stRow, node.stCol);
throw new Exception(errorString);
}
return(Convert.ToDouble(left) - Convert.ToDouble(right));
case TokenType.div:
left = evalNode(node.left);
right = evalNode(node.right);
if (left is string || right is string)
{
string errorString = string.Format("Incompatible types at line {0} position {1}.", node.stRow, node.stCol);
throw new Exception(errorString);
}
//x = Convert.ToDouble(right);
//if (x == 0)
//{
// string errorString = string.Format("Division by zero at line {0} position {1}.", node.right.stRow, node.right.stCol);
// throw new Exception(errorString);
//}
//return x / y;
return(Convert.ToDouble(left) / Convert.ToDouble(right));
case TokenType.pow:
left = evalNode(node.left);
right = evalNode(node.right);
if (left is string || right is string)
{
string errorString = string.Format("Incompatible types at line {0} position {1}.", node.stRow, node.stCol);
throw new Exception(errorString);
}
return(Math.Pow(Convert.ToDouble(left), Convert.ToDouble(right)));
case TokenType.fact:
left = evalNode(node.left);
if (left is string)
{
string errorString = string.Format("Incompatible types at line {0} position {1}.", node.stRow, node.stCol);
throw new Exception(errorString);
}
return(factorial(Convert.ToDouble(left)));
case TokenType.identifier:
object value;
if (_level > 0)
{
if (_args.TryGetValue(node.name, out value))
{
return(value);
}
}
if (!_consts.TryGetValue(node.name, out value))
{
if (!_libVariables.TryGetValue(node.name, out value))
{
if (!_variables.TryGetValue(node.name, out value))
{
string errorString = string.Format("Undefined ident \"{0}\" at line {1} position {2}.", node.name, node.stRow, node.stCol);
throw new Exception(errorString);
}
}
}
return(value);
case TokenType.assign:
if (_consts.TryGetValue(node.name, out value))
{
string errorString = string.Format("Invalid lvalue \"{0}\" at line {1} position {2}.", node.name, node.stRow, node.stCol);
throw new Exception(errorString);
}
if (_libMode)
{
_libVariables[node.name] = evalNode((Symbol)node.value);
}
//return _libVariables[node.name];
else
{
if (_libVariables.TryGetValue(node.name, out value))
{
string errorString = string.Format("Invalid lvalue \"{0}\" at line {1} position {2}.", node.name, node.stRow, node.stCol);
throw new Exception(errorString);
}
_variables[node.name] = evalNode((Symbol)node.value);
//return _variables[node.name];
}
return(null);
case TokenType.call:
bool builtIn = true;
if (!_builtInFunctions.ContainsKey(node.name))
{
if (!_userFunctions.ContainsKey(node.name))
{
string errorString = string.Format("Undefined function \"{0}\" at line {1} position {2}.", node.name, node.stRow, node.stCol);
throw new Exception(errorString);
}
builtIn = false;
}
foreach (var arg in node.args)
{
_argValues.Add(evalNode(arg));
}
_level++;
object ret = builtIn ? _builtInFunctions[node.name]() : _userFunctions[node.name]();
_level--;
if (_argValues.Count > node.args.Count)
{
_argValues.RemoveRange(_argValues.Count - node.args.Count, node.args.Count);
}
else
{
_argValues.Clear();
}
return(ret);
case TokenType.function:
if (_libMode)
{
_builtInFunctions[node.name] = () =>
{
for (var i = 0; i < node.args.Count; i++)
{
_args[node.args[i].name] = getArgValue(node.args.Count - 1 - i);
}
object result = evalNode((Symbol)node.value);
_args.Clear();
return(result);
}
}
;
else
{
if (_builtInFunctions.ContainsKey(node.name) || _userFunctions.ContainsKey(node.name))
{
//string errorString = string.Format("Function \"{0}\" at line {1} position {2} alredy exist.", node.name, node.stRow, node.stCol);
string errorString = string.Format("Symbol \"{0}\" at line {1} position {2} alredy defined.", node.name, node.stRow, node.stCol);
throw new Exception(errorString);
}
_userFunctions[node.name] = () =>
{
for (var i = 0; i < node.args.Count; i++)
{
_args[node.args[i].name] = getArgValue(node.args.Count - 1 - i);
}
object result = evalNode((Symbol)node.value);
_args.Clear();
return(result);
};
}
return(null);
}
return(null);
}