(shell) Support multiline commands

[ggrossetie]

resolve #2860

Changes

Add support for multi-line commands using the line continuation \.

Checklist

• Added markup tests
• Updated the changelog at CHANGES.md
• Added myself to AUTHORS.txt, under Contributors

[ggrossetie]

end: '(?=[^\\\\]\\s*$)', subLanguage: 'bash'

Does that fix the test?

I think you have the right idea but this regular expression does not work. It actually excludes the last character.
The following:

$ /bin/sh

now produces:

<span class="hljs-meta">$</span><span class="bash"> /bin/s</span>h

(notice the letter "h" is outside the "bash" span)

[ggrossetie]

@joshgoebel I think we need to use a negative lookbehind. Basically the line must not end with a line continuation, so the end of a line must not be preceded by zero or more spaces and the character "\".
Unfortunately, lookbehind assertions are not supported in a few browsers: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp#Browser_compatibility

I'm not sure how it can be rewritten without a lookbehind because the end position should always be the end of the line ($) unless there's a line continuation just before the end of a line. That's by definition a lookbehind assertion.

[joshgoebel]

I think we need to use a negative lookbehind.

Yep, not allowed as you pointed out because Safari still lags.

---

So let's include the last character and use the look-ahead to find the end of line.

end: /[^\\](?=\s*$)/,

Thoughts? I pushed my changes.

[ggrossetie]

Thoughts? I pushed my changes.

Oh nice, if it works then 👍
I will add a few tests to make sure that it's working as expected (and also rebase/resolve the conflict) then we are good to go!

EDIT: I can confirm that this is working great 🎉

[ggrossetie]

@joshgoebel I'm confused, this language improvement is not part of the 10.4.0-beta1 right?

[joshgoebel]

Correct really they heading should probably change. Betas aren’t the same as releases though they’re rolling so things just keep getting added until we have a release

[joshgoebel]

So really the header and should be 10.4 rolling or some such. I’ll give it some thought. I only updated it because we have to update the header for production releases but that’s not true for beta releases so we have more flexibility there.