Add support for ALE, the Async Linting Engine

[neersighted]

Ale is a plugin that lints text in the background, as you type!

It is new, but under rapid development.

[w0rp]

This looks okay to me. I'll leave this for airline contributors to look at.

[chrisbra]

could someone test this please?

[neersighted]

This is currently waiting on dense-analysis/ale#97. As far as testing, it works on all my machines, but third-party tests would be great.

[neersighted]

The blocker is now merged, so this is good to go again.

[chrisbra]

thanks. included

[unphased]

@chrisbra do you think you could give me some pointers on how to extend the ALE plugin to use the autocmd User ALELintPre and autocmd User ALELintPost autocmds to give a realtime color indicator of ALE lint job status?

I want that feedback because linting (especially c++) can sometimes bring the system to its knees. Such an indicator would help for peace of mind...

[chrisbra]

the airline plugin does not trigger the Ale linting, it only shows the result (e.g. is merely calls ale#statusline#get() function). Try asking @w0rp as it is his plugin and he did most of the airline extension.

[unphased]

@chrisbra I am well aware of this. I'm referring to the autocommands run by ALE when linting proceeds. I just need documentation on basic airline section color updating, that's it...

[chrisbra]

There is nothing like a specific highlighting parts of a section. However you could use User highlighting and add some parts to the statusline (including the User highlighting group).

[unphased]

I am unable to find docs on what User highlighting means. I see that it is used by these autocommands. Thanks for the help.

[unphased]

Is User just like any other highlight group, and just a standard Vim placeholder one for user to customize? That's fine. I'd like to just make the warn/error section to change color.

[chrisbra]

You need to define any of the User1 till User9 highlighting group. Then in the airline section, you can use %1*text%0* to set use highlighting group User1 for text text.

[unphased]

Thanks, that would have taken a loooong time for me to figure out on my own :)

So this means i can then just update the content of the section and it will change color?

[chrisbra]

Well, you either need to redefine the highlighting group or use a different one, depending on what you want.

[unphased]

:hi User1
User1          xxx ctermbg=52 guibg=#803030

(the User1 looks the way i set it)

i'm guessing the interpretation happens somewhere so i need to put the string somewhere special

when i grep airline repo for User all i get are matches for autocommands.

[chrisbra]

ah okay, that would need to be defined differently I think. It might be simpler to just redefine airline_warning and airline_highlighting group

[unphased]

I don't know what highlighting group is, but I found airline#highlighter#exec in #1495 and will try hacking a little.

[chrisbra]

the highlighting group is used by the ale extension. airline_warning for the warning section and airline_error for the error part.

[unphased]

I am able to manipulate the color of the warning section by doing this:

:call airline#highlighter#exec('airline_warning', airline#themes#get_highlight('Select')) " select is just an arbitrary highlight that i chose to try

but it reverts back instantly. How can I (semi-)permanently update the color of one of these sections? Alternatively, how can I add a wholly new section at the end which I want to make visible dynamically? The latter would probably be easier!