RegExp `x` flag

Jacob Pratt jhprattdev at gmail.com
Tue Jun 4 03:27:06 UTC 2019


Even if this flag were restricted to constructors instead of both
constructors and literals, it could be worthwhile.

On Mon, Jun 3, 2019, 23:19 Isiah Meadows <isiahmeadows at gmail.com> wrote:

> Let me clarify that previous message: I mean "newline restriction" in
> the sense that newlines are not permitted in regexp literals. A `/x`
> flag would make removing it practically required for it to have any
> utility.
>
> -----
>
> Isiah Meadows
> contact at isiahmeadows.com
> www.isiahmeadows.com
>
> On Mon, Jun 3, 2019 at 11:14 PM Isiah Meadows <isiahmeadows at gmail.com>
> wrote:
> >
> > I would personally love this (as well as interpolations in regexp
> > literals). I do have a concern about whether removing the newline
> > restriction creates ambiguities with division, but I suspect this is
> > *not* the case.
> >
> > -----
> >
> > Isiah Meadows
> > contact at isiahmeadows.com
> > www.isiahmeadows.com
> >
> > On Mon, Jun 3, 2019 at 10:03 PM Jacob Pratt <jhprattdev at gmail.com>
> wrote:
> > >
> > > Has there been any previous discussion of adding the `x` flag to JS?
> It exists in other languages, and can make relatively complicated regex
> _much_ easier to read. It also allows for comments, which are incredibly
> helpful when trying to understand some regexes.
> > >
> > > For prior art, XRegExp has this flag (though I've no idea to figure
> out how frequently it's used), as do a few other languages.
> > >
> > > Quick overview: https://www.regular-expressions.info/freespacing.html
> > >
> > > Language references:
> > > Python: https://docs.python.org/3/library/re.html#re.X
> > > Rust: https://docs.rs/regex/1.1.6/regex/
> > > XRegExp: http://xregexp.com/xregexp/flags/#extended
> > > .NET:
> https://docs.microsoft.com/en-us/dotnet/standard/base-types/regular-expression-language-quick-reference#regular-expression-options
> > >
> > > Jacob Pratt
> > > _______________________________________________
> > > es-discuss mailing list
> > > es-discuss at mozilla.org
> > > https://mail.mozilla.org/listinfo/es-discuss
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.mozilla.org/pipermail/es-discuss/attachments/20190603/40fca066/attachment-0001.html>


More information about the es-discuss mailing list