panic: (anonymous): Line 26506:51 Invalid regular expression: re2: Invalid (?=) <lookahead>

[xinstein]

I'm trying to use pacproxy to convert shadowsocks pac to simple http proxy, but faced this error.

I actually located some ?='s in the shadowsocks generated pac file:
....
Filter.elemhideRegExp = /^([^\/\*\|\@"!]*?)#(\@)?(?:([\w\-]+|\*)((?:\([\w\-]+(?:[$^*]?=[^\(\)"]*)?\))*)|#([^{}]+))$/;
....
var candidates = text.toLowerCase().match(/[^a-z0-9%*][a-z0-9%]{3,}(?=[^a-z0-9%*])/g);
....