private string evalSignOperator(SignOperatorToken token)
{
string expr = token.SubTokens[1].Evaluate(this);
bool brackets = token.SubTokens[1] is OperatorToken;
if (brackets)
{
expr = $"<mo>(</mo>{expr}<mo>)</mo>";
}
return($"<mo>{token.Symbol}</mo>" + expr);
}
private string evalSignOperator(SignOperatorToken token)
{
string expr = token.SubTokens[1].Evaluate(this);
bool brackets = token.SubTokens[1] is OperatorToken;
if (brackets)
{
expr = String.Format("({0})", expr);
}
return(token.Symbol + expr);
}
/// <summary>
/// Reads the next token from the input stream and adds it to the given token list.
/// </summary>
private Token readNextToken(LinkedList <Token> tokenList, Token lastToken, InputStream str)
{
if (str.AtEnd)
{
throw new ParserSyntaxException(str.Position);
}
// Check for numbers
if (numberReader(str, out Token outtok))
{
tokenList.AddLast(outtok);
return(outtok);
}
// Check for operators, functions, vars
foreach (var item in TokenDict)
{
int pos = str.Position;
if (str.StartsWith(item.Key))
{
Token newToken;
if (item.Value.Item2 != 0)
{
newToken = (Token)Activator.CreateInstance(item.Value.Item1, item.Key, pos, item.Value.Item2);
}
else if (item.Value.Item1 == typeof(LeftBracketToken) || item.Value.Item1 == typeof(RightBracketToken))
{
newToken = (Token)Activator.CreateInstance(item.Value.Item1, pos);
}
else
{
newToken = (Token)Activator.CreateInstance(item.Value.Item1, item.Key, pos);
}
// Special handling for '+' and '-' signs
if (lastToken is null || lastToken is StructToken || lastToken is LeftBracketToken)
{
if (item.Key == ParserSymbols.Add)
{
Token nextToken = readNextToken(tokenList, newToken, str);
if (nextToken is OperatorToken)
{
throw new ParserSyntaxException("Invalid operator sequence.", pos);
}
return(nextToken);
}
else if (item.Key == ParserSymbols.Subtract)
{
var signToken = new SignOperatorToken(pos);
tokenList.AddLast(signToken);
return(signToken);
}
}
// Special handling for syntax that omits the '*' operator
if (newToken is VarToken || newToken is ConstantToken)
{
if (lastToken is NumberToken)
{
tokenList.AddLast(new OperatorToken(ParserSymbols.Multiply, pos));
}
}
tokenList.AddLast(newToken);
return(newToken);
}
}
// If no valid valid token was found
throw new ParserCharException(str.Position, str.FirstChar());
}
