There seem to be some bugs with the parsing of an escaped backslash:

So, two issues:

1. The syntax highlighter doesn't stop parsing the line as a string if it encounters two backslashes in a row, although it will run without problems
2. ...except when used as an argument to the ? shorthand function, which will give an error

It's not in the screenshot, but if there are any trailing characters after the double backslash, the syntax highlighter will be happy again.

I see this has been reported before, sorry: https://www.lexaloffle.com/bbs/?tid=3062

The ? behavior is probably new though.

Fixed in 0.1.12, thanks.

Fixed: preprocessor breaks on double slash in string s="\\"