public Node ParseOperand()
{
//NOTE(patrik): Parse Numbers, Power, Paren, Function operations
if (lexer.CurrentToken == TokenType.NUMBER)
{
// Format 1: number
// 2: number^number
double value = lexer.CurrentNumber;
lexer.NextToken();
if (lexer.CurrentToken == TokenType.POWER)
{
lexer.NextToken();
double power = lexer.CurrentNumber;
lexer.ExpectToken(TokenType.NUMBER);
return(new POWNode(value, power));
}
return(new NumberNode(value));
}
else if (lexer.CurrentToken == TokenType.MINUS)
{
// Format 1: -number
lexer.NextToken();
double value = lexer.CurrentNumber;
lexer.ExpectToken(TokenType.NUMBER);
return(new NumberNode(-value));
}
else if (lexer.CurrentToken == TokenType.OPEN_PAREN)
{
// Format 1: (expr)
lexer.NextToken();
Node result = Parse();
lexer.ExpectToken(TokenType.CLOSE_PAREN);
return(result);
}
else if (lexer.CurrentToken == TokenType.IDENTIFIER)
{
// Format 1: identifier
// 2: identifier(expr, ...)
string identifier = lexer.CurrentIdentifier;
lexer.NextToken();
if (lexer.CurrentToken == TokenType.OPEN_PAREN)
{
lexer.NextToken();
Node node = Parse();
lexer.ExpectToken(TokenType.CLOSE_PAREN);
if (identifier.Equals("sqrt", StringComparison.OrdinalIgnoreCase))
{
SQRTNode result = new SQRTNode(node);
return(result);
}
}
}
return(null);
}
