The meaning of a string literal in an expression

[cornmonster]

Hi guys, I am a little confused by the STRING_LITERAL in the expression:

expression
    : LR_BRACKET unaryInBracket=expression RR_BRACKET
    | (PLUS | MINUS) unaryAfterSign=expression
    | leftExpression=expression (STAR | DIV | MOD) rightExpression=expression
    | leftExpression=expression (PLUS | MINUS) rightExpression=expression
    | functionName LR_BRACKET expression (COMMA expression)* functionAttribute* RR_BRACKET
    | suffixPath
    | literal=STRING_LITERAL
    ;

And in the IoTDBSQLVisitor#parseExpression, the string literal is treated as a suffix path:

    // suffixPath
    if (context.suffixPath() != null) {
      return new TimeSeriesOperand(parseSuffixPath(context.suffixPath()));
    }

    // literal=SINGLE_QUOTE_STRING_LITERAL
    if (context.literal != null) {
      return new TimeSeriesOperand(new PartialPath(new String[] {context.literal.getText()}));
    }

So I can execute the following query without any exception, which is quite unintuitive:

SELECT 's1' FROM roog.sg.d1

I am not sure about the reason for this implementation. Can anyone give me some hints?

Thanks,
Zhong

[cornmonster]

@liuminghui233 Hi, I noticed you refactored the ANTLR part recently, could you please have a look at this question? thanks!