There's no need to add complexity of single-character identity escapes for every ASCII punctuator. I would prefer escaping using hex escape sequences instead, as discussed in #58. The only argument given against this is that you'd have to copy-paste any RegExp constructed using this function into a RegExp explainer to understand it, but let's be honest, you were going to have to do that anyway. @sophiebits also points out that by not modifying the grammar, we allow this feature to be polyfilled in older browsers.