add toggle-block-comment

[takase1121]

This is requested from Discord. The support is rather rudimentary - no support for comment nesting, etc.

It might not work well with unicode characters. I'll need guidance to make them work.

[Guldoman]

I haven't looked at the code yet, but do you think we could make doc:toggle-line-comments fallback to doc:toggle-block-comments when the user wants to comment a single line, but the language only supports multiline comments?

[takase1121]

I renamed the key to block_comment because its more suitable.

[Guldoman]

A couple of problems I encountered:

• When there is a selection, only the selected part is commented. Is this intended?
• The comment always starts at the beginning of the line, while toggle-line-comments starts from the position of the text.

Also, do you think we can improve this functionality to respect nested syntaxes or would that be too complex?

[adamharrison]

I really like this. It's good stuff.

When there is a selection, only the selected part is commented. Is this intended?

I can only assume this is intended. This is how I'd expect it to work.

The comment always starts at the beginning of the line, while toggle-line-comments starts from the position of the text.

In the version I just built, here's the behaviour I'm seeing:

Command	Selection	Result
toggle-line-comments	No Selection	Insert beginning of line comment.
toggle-line-comments	Single Line Selection	Insert beginning of line comment.
toggle-line-comments	Multiple Line Selection	Insert beginning of each line comment.
toggle-block-comments	No Selection	Wraps entire line.
toggle-block-comments	Single Line Selection	Wraps selection.
toggle-block-comments	Multiple Line Selection	Wraps selection.

All of these behaviours make sense to me.

Also, do you think we can improve this functionality to respect nested syntaxes or would that be too complex?

Yeah; that's a good point. Currently, toggle-line-comments doesn't do this, so this would be a general enhancement anyway.

My vote is, let's merge this (if @Guldoman you're cool with the behaviour in that table, and that's what you're seeing as well), and we can add in support for the commenting functions hitting subsyntaxes in another PR (unless you wanna just slip that in @takase1121 ).

[Guldoman]

The behavior is different from atom and vscode, as both of them start the block comment after the indentation. They also wrap the entire line, not just the selection.
In the end it's fine like this too, but I do prefer the other way.

My vote is, let's merge this (if @Guldoman you're cool with the behaviour in that table, and that's what you're seeing as well), and we can add in support for the commenting functions hitting subsyntaxes in another PR (unless you wanna just slip that in @takase1121 ).

Yeah, it works so LGTM.

[adamharrison]

The behavior is different from atom and vscode, as both of them start the block comment after the indentation.

Aha; OK, sorry, I misunderstood what you meant when you said "beginning of the text". Gotcha. In that case, yeah; I think we should probably follow that convention, then. That's currently also a problem with line comments again, so yeah; I think we should have another PR to fix up that behaviour.

They also wrap the entire line, not just the selection.

Hrm. I booted up atom, but don't seem to have an obvious "block comment" function; I only have "Editor: Toggle Line Comments". What's the command for that in atom?

For vscode; I checked, and it does seem to be block commenting from the selection, not the entire line. What language did you try? I tried HTML and JavaScript.

[Guldoman]

That's currently also a problem with line comments again, so yeah; I think we should have another PR to fix up that behaviour.

Line comments start correctly after the indentation for me. Both with single line and multi-line selections.

Hrm. I booted up atom, but don't seem to have an obvious "block comment" function; I only have "Editor: Toggle Line Comments". What's the command for that in atom?

I used that command in an HTML file, it does the block comment (but it might be a plugin, I don't know).

For vscode; I checked, and it does seem to be block commenting from the selection, not the entire line. What language did you try? I tried HTML and JavaScript.

This is how it works for me:

• Atom
  
• VSCodium
  

Edit: it looks like VSCodium does comment only the selection, but only with the block comment command, not the normal line comment.

[adamharrison]

Line comments start correctly after the indentation for me. Both with single line and multi-line selections.

Ah; sorry, yeah. This PR changes that; master performs correctly. So that's actually a regression that should be fixed.
UPD: Ok, now wait a minute. This seems to change depending on syntax. Let me look into this a little more.
UPD2: OK, I can't actually reproduce this now. Weird. Maybe I just got confused. But yes; block comments should start at the beginning of indents if no selection, as line comments do, 100% agreed.
UPD3: OK, actually, found it. It's because in HTML, there are no non-block comments, so it's running through the block logic. So it's actually that first issue you mention; that block comments just don't indent properly. So yeah. That should be fixed, then this is all good.

I used that command in an HTML file, it does the block comment (but it might be a plugin, I don't know).

Well, there is no line comment in HTML; so the block comment makes sense, but given a bit of googling, it doesn't actually appear that atom has a block comment command out of the box; so I say we discount atom's behaviour for now.

Edit: it looks like VSCodium does comment only the selection, but only with the block comment command, not the normal line comment.

Right. I think that's reasonable (and I think that's what this PR currently does, yeah?).

[Guldoman]

Line comments start correctly after the indentation for me. Both with single line and multi-line selections.

Ah; sorry, yeah. This PR changes that; master performs correctly. So that's actually a regression that should be fixed.

This PR regresses the single line comment command only when it needs to call the block comment command.

I used that command in an HTML file, it does the block comment (but it might be a plugin, I don't know).

Well, there is no line comment in HTML; so the block comment makes sense, but given a bit of googling, it doesn't actually appear that atom has a block comment command out of the box; so I say we discount atom's behaviour for now.

Just tested Atom in safe mode (I think we need a safe mode too), and it has the same behavior, so it wasn't a plugin.

So it seems that in the end the behaviors are:

• Single line comments: comment the entire line, starting after the indentation; if no simple line comment exists for that language, the behavior remains unchanged and instead uses the block comment syntax.
• Block comments: comment only the selection.

So the only thing this PR is "missing" is the possibility of commenting the entire line, starting after the indentation, when calling the single line comment (and no simple line comment is available).

Also, testing more, VSCodium seems to not wrap the entire line when there isn't a selection, but it just adds the block comment where the caret is. I don't know how to feel about this.

[adamharrison]

This PR regresses the single line comment command only when it needs to call the block comment command.

Yeah, you're right. It's even less a regression, and more an expansion of functionality (because you can't even comment line comment HTML in master, for example) that just was not as expected.

Just tested Atom in safe mode (I think we need a safe mode too), and it has the same behavior, so it wasn't a plugin.

Agreed. Functionally that can be achieved by setting your XDG_CONFIG_HOME to an empty folder, but we probably want a less esoteric way to do it. (Command line options?)

But yeah; sorry, I don't mean that the behaviour was a plugin, I mean that it doesn't have an explicit command for block comments, so regardless of which behaviour it chooses, I don't think we should use it as a model for block-style commenting, because there's no explicit ask to perform a particular style of commenting; there's only the ask for line-style commenting, which is semantically different from block-style commenting. In Atom, it's basically only ever doing line-style commenting (even if it's using block comments).

So it seems that in the end the behaviors are:

Single line comments: comment the entire line, starting after the indentation; if no simple line comment exists for that language, the behavior remains unchanged and instead uses the block comment syntax.
Block comments: comment only the selection.

So the only thing this PR is "missing" is the possibility of commenting the entire line, starting after the indentation, when calling the single line comment (and no simple line comment is available).

Yeah. Given the behaviour in vscode, that if you do toggle-line-comments, it should always follow the line conventions, and if you toggle-block-comments, it should follow the block conventions; regardless of whether or not the syntax defines a line or a block comment. Agreed.

Also, testing more, VSCodium seems to not wrap the entire line when there isn't a selection, but it just adds the block comment where the caret is. I don't know how to feel about this.

I am not a huge fan of that either. If no one objects, I'd be happy if we made that act like a line comment.

[Guldoman]

Agreed. Functionally that can be achieved by setting your XDG_CONFIG_HOME to an empty folder, but we probably want a less esoteric way to do it. (Command line options?)

Command line parsing would be great, yes.

Yeah. Given the behaviour in vscode, that if you do toggle-line-comments, it should always follow the line conventions, and if you toggle-block-comments, it should follow the block conventions; regardless of whether or not the syntax defines a line or a block comment. Agreed.

Yep, I'm OK with this behavior.

Also, testing more, VSCodium seems to not wrap the entire line when there isn't a selection, but it just adds the block comment where the caret is. I don't know how to feel about this.

I am not a huge fan of that either. If no one objects, I'd be happy if we made that act like a line comment.

My vote goes for full line comment too, as I don't think adding the block comment in the middle of a line is used much, but I could be wrong.

[takase1121]

The comment always starts at the beginning of the line, while toggle-line-comments starts from the position of the text.

Not sure how I would do this.

[adamharrison]

Not sure how I would do this.

I think Guldo just means that we should just mirror the behaviour of toggle-line-comments in the positioning of the block comment when you have nothing selected, and the syntax only supports block comments.

UPD: I messed this up. HTML is a better example:

i.e. if you have

      <hr/>

And you comment it with a line comment, it becomes

<!--      <hr/> -->

The suggestion is that instead it becomes:

      <!-- <hr/> -->

[takase1121]

Alright, I've refactored the code and also make it whitespace aware. The cols are normalised to word start and end before anything is done, so cases like

    hello
    world    |

(| marks EOL)

would work.

[adamharrison]

Looks good. I'm happy to merge this now; just one last nitpick.

When I toggle a line comment, it selects the whole commented line. Can we change it so the cursor just stays where it is? (this is the behaviour in VScode and atom).

[Guldoman]

This still doesn't distinguish between line and block comments when dealing with languages that only have one or the other.

What I mean is that the line comment command should always comment the whole line/s, as opposed to block comment that should comment only what's selected.

So now in HTML for example, calling the line comment command with multiple selected lines, it comments only the selection, while it should comment from the beginning of the first line, to the end of the last, in a single comment block.

In the end the current behavior is ok, so we could just merge this in, and iron out the corner cases later.

[takase1121]

Looks good. I'm happy to merge this now; just one last nitpick.

When I toggle a line comment, it selects the whole commented line. Can we change it so the cursor just stays where it is? (this is the behaviour in VScode and atom).

I can fix that.

This still doesn't distinguish between line and block comments when dealing with languages that only have one or the other.

What I mean is that the line comment command should always comment the whole line/s, as opposed to block comment that should comment only what's selected.

So now in HTML for example, calling the line comment command with multiple selected lines, it comments only the selection, while it should comment from the beginning of the first line, to the end of the last, in a single comment block.

In the end the current behavior is ok, so we could just merge this in, and iron out the corner cases later.

I understand your meaning.
if we have selected the entire line,

If I press ctrl+/, it should be

Instead of

Right?

[Guldoman]

Basically if there is a single line comment defined for the language, calling toggle-line-comments:

Selection	Result
No Selection	Insert line comment at text start.
Single Line Selection	Insert line comment at text start.
Multiple Line Selection	Insert line comment at text start for each line.

If there is not:

Selection	Result
No Selection	Insert block comment from line text start, to line end.
Single Line Selection	Insert block comment from line text start, to line end.
Multiple Line Selection	Insert block comment from first line text start, to last line end.

Calling toggle-block-comments is fine as it is now, but I haven't tested what happens if the language doesn't use block comments.

[takase1121]

I think I adressed it with my latest commit.

[adamharrison]

Looking good; one last thing. Toggling line comments in this situation:

Leads to this selection, which is kinda weird.

Should probably select the whole line. Same thing happens in C.

Block commenting works perfectly, as far as I can tell.

[Guldoman]

Yep, this seems fine.
The behavior of line comment on multiple lines selection is a bit different than what I expected, but it's still fine (I'd even say it's more logical the way it's implemented with a new block comment for each line).

This behavior shows a little "problem": it inserts the line comment at each line "text start", while the normal line insert keeps the smallest indent.

Indent on the same row:	Indent on "text start":

But I think we could just merge this as it is.

[adamharrison]

This mostly works; so with @takase1121 's blessing, I'm merging this, and we'll fix up those last little issues in another PR. It's still much better than what we've got currently.