Hacker News Reader

But that's also stupid because you cannot actually simplify the parser that much then, as you still need to detect it. And then you could just keep supporting it anyways, since it pretty much calls into the same code as the surrounding curly braces after that.

I mean, you could just set the parser to throw an exception if it ever detects anything other than a character (a-zA-Z) after an un-escaped dollar sign. Then you can just throw the same error, "Invalid string interpolation" so that no internal state of your program leaks, and you can immediately skip any subsequent memory reads for the contents of the variable.

A syntax error would be \s fun though, would you have to escape the sequence in order to get that intentionally?

If you have display_errors on, you have much security risk than this.