Regexp literal escaping

[cyriltovena]

Is your feature request related to a problem? Please describe.

For filter expression and soon to come extract expression, regexp can be difficult to write. Because of the quoted string {app="foo"} |= "\\w+" the normal string escape rules (preceding special characters with \ when included in a string) are necessary. This causes regular expression to be converted.

Describe the solution you'd like
Javascript has 2 ways of declaring regexp see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp

The literal notation's parameters are enclosed between slashes and do not use quotation marks.
The constructor function's parameters are not enclosed between slashes but do use quotation marks.

Example:

let re = /\w+/
let re = new RegExp('\\w+')

As you can see the first one doesn't need escape.

So my suggestion is to support the two syntax:

• {app="foo"} |= "\\w+"
• {app="foo"} |= /\w+/

Describe alternatives you've considered
Do nothing and live with it, personally sometimes it a pain to prepare a regex in an online editor and then have to fiddle with it to make sure everything is escaped correctly.

Additional context
Here is a example that was difficult to build for this reason:

/cc @owen-d @slim-bean if we have consensus I could work on that.

[owen-d]

lgtm - go for it!

[slim-bean]

love it!

[cyriltovena]

I don't think we can support this with the current lexer. We might need to build our own.

/cc @owen-d

[cyriltovena]

Fixed by #2095