private bool IsUnaryOperator(string current, string?prev, string?next)
{
IMathContext context = Context;
if (!context.TryGetUnaryOperator(current, out var op))
{
return(false);
}
if (op.Notation == OperatorNotation.Prefix)
{
if (prev != null && (prev == ")" ||
IsNumber(prev) ||
context.IsVariableOrConstant(prev) ||
(context.IsUnaryOperator(prev) && !context.IsBinaryOperator(prev))))
{
return(false);
}
return(next != null && !IsValidOperator(next[0]) && (next == "(" || char.IsLetterOrDigit(next[0])));
}
else if (op.Notation == OperatorNotation.Postfix)
{
return(prev != null && (prev == ")" || IsNumber(prev) || context.IsVariableOrConstant(prev)));
}
else
{
return(false);
}
}
private Token[] GetTokensInternal(string[] arr)
{
if (arr.Length == 0)
{
return(Array.Empty <Token>());
}
List <Token> tokens = new List <Token>(arr.Length);
IMathContext context = Context;
int length = arr.Length;
for (int i = 0; i < length; i++)
{
string current = arr[i];
if (IsNumber(current))
{
tokens.Add(new Token(current, TokenType.Number));
}
else if (context.IsVariableOrConstant(current))
{
tokens.Add(new Token(current, TokenType.VariableOrConstant));
}
else if (context.IsFunction(current))
{
tokens.Add(new Token(current, TokenType.Function));
}
else if (context.IsBinaryOperator(current) || context.IsUnaryOperator(current))
{
string?prev = i > 0 ? arr[i - 1] : null;
string?next = i < length - 1 ? arr[i + 1] : null;
if (IsUnaryOperator(current, prev, next))
{
tokens.Add(new Token(current, TokenType.UnaryOperator));
}
else
{
tokens.Add(new Token(current, TokenType.BinaryOperator));
}
}
else if (current == "(" || current == ")")
{
tokens.Add(Token.FromParenthesis(current[0]));
}
else if (current == ",")
{
tokens.Add(Token.Comma);
}
else
{
tokens.Add(new Token(current, TokenType.Unknown));
}
}
return(tokens.ToArray());
}