src/main/java/com/bazaarvoice/jless/parser/Parser.java
Rule Unicode() {
        return Sequence(
                '\\',
                Hex(), Optional(Hex(), Optional(Hex(), Optional(Hex(), Optional(Hex(), Optional(Hex()))))),
                Optional(Whitespace())
        );
    }
Rule Unicode() {
        return Sequence(
                '\\',
                Hex(), Optional(Hex(), Optional(Hex(), Optional(Hex(), Optional(Hex(), Optional(Hex()))))),
                Optional(Whitespace())
        );
    }
'\' [0-9a-fA-F]{1,6} wc?