Does it still read the string? On Fri, Nov 6, 2015, 20:59 Gorkem Yakin <goya...@microsoft.com> wrote:
> 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:es-discuss-boun...@mozilla.org] *On Behalf Of > *Isiah > Meadows > *Sent:* Friday, November 6, 2015 4:36 PM > *To:* C. Scott Ananian <ecmascr...@cscott.net>; Brian Terlson < > brian.terl...@microsoft.com> > *Cc:* es-discuss@mozilla.org > *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 <ecmascr...@cscott.net> wrote: > > On Fri, Nov 6, 2015 at 1:20 PM, Brian Terlson > <brian.terl...@microsoft.com> 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 > es-discuss@mozilla.org > 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> > >
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