/// FACTOR: '-'? EXPONENT
private ASTNode ParseFactor( )
{
ASTNode node = default;
if (IsNext(Token.TokenType.Minus))
{
node = new NegationUnaryOperatorASTNode(Accept( ), ParseExponent( ));
}
else
{
node = ParseExponent( );
}
return(node);
}
/// FACTOR: '-'? IMPLICT_MUL
private bool TryParseFactor(out ASTNode node)
{
if (IsNext(Token.TokenType.Minus))
{
var op = Accept( );
if (TryParseImplictMultiplication(out node))
{
node = new NegationUnaryOperatorASTNode(op, node);
}
else
{
throw new Exception($"Exception Parsing the Factor Rule at Position {_lexer.Position}");
}
}
else
{
TryParseImplictMultiplication(out node);
}
return(node != null);
}
protected double Evaluate(NegationUnaryOperatorASTNode node) => - 1 * Evaluate(node.Target as dynamic);