I don’t know about other engines, but Chakra does cache the RegExp matcher when the RegExp object is created via the constructor.
Gorkem From: es-discuss [mailto:[email protected]] On Behalf Of Isiah Meadows Sent: Friday, November 6, 2015 4:36 PM To: C. Scott Ananian <[email protected]>; Brian Terlson <[email protected]> Cc: [email protected] Subject: Re: RegExp free-spacing & comments The problem with using the RegExp constructor is that it is never cached by the engine. As a literal, engines usually internalize them, speeding up matches very quickly. On Fri, Nov 6, 2015, 14:24 C. Scott Ananian <[email protected]<mailto:[email protected]>> wrote: On Fri, Nov 6, 2015 at 1:20 PM, Brian Terlson <[email protected]<mailto:[email protected]>> wrote: > RegExp.re or similar seems nice: > > ``` > let re = RegExp.re("x")` > (\d{3}-)? # area code (optional) > \d{3}- # prefix > \d{4} # line number > `; > ``` > > But it seems like previous proposals of this want escaping which doesn't seem > ideal for this purpose. Do we need both `RegExp.re` and `RegExp.escapedRe`? Escaping happens if you use interpolation into the string template: ``` let re = RegExp.re`(?x: (\d{3}-)? # area code (optional) ${ /\d{3}/ }- # prefix \d{4} # line number ( ${ "*" } \d+ )? # extension )`; ``` If the interpolated expression is a regexp, then things seem relatively straightforward (although there are corner cases to consider). If the interpolated expression is a string, then it is suggested that you use some sort of automatic escaping. --scott _______________________________________________ es-discuss mailing list [email protected]<mailto:[email protected]> https://mail.mozilla.org/listinfo/es-discuss<https://na01.safelinks.protection.outlook.com/?url=https%3a%2f%2fmail.mozilla.org%2flistinfo%2fes-discuss&data=01%7c01%7cgoyakin%40microsoft.com%7c0ebaa0e85f994ffe3c0708d2e70b81db%7c72f988bf86f141af91ab2d7cd011db47%7c1&sdata=g9mQNk%2bq0%2bD8%2bwq6NdZf95q9eWMoaq2OhvMhT3kwiRs%3d>
_______________________________________________ es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
