Comments autoformatted even without formatoptions 'c' flag

[msuperdock]

Note: I also filed this as a neovim issue here.

• Version: 8.1.146 (also affects neovim 0.3.1)
• Operating system/version: NixOS 18.09
• Terminal name/version: st-0.8.1
• $TERM: st-256color

Steps to reproduce using vim -u NONE

vim -u NONE
:set fo=ta<cr>i% test<cr>% test

Actual behaviour

On typing the second '%', autoformatting kicks in, and the two lines are combined into one. The final result is a single line:

% test % test

Expected behaviour

Since :set comments gives a string including ":%", I expect that when I type the second '%', vim recognizes the second line as a comment and does not combine the two lines into one, since formatoptions does not include the c flag. My expected final result is:

% test
% test

Explanation

The documentation for fo-table says:

With 't' and 'c' you can specify when Vim performs auto-wrapping:
value action
"" no automatic formatting (you can use "gq" for manual formatting)
"t" automatic formatting of text, but not comments
"c" automatic formatting for comments, but not text (good for C code)
"tc" automatic formatting for text and comments

When we use set fo=ca, we get the nice behavior where no automatic formatting is done outside of comments, but comments reflow automatically. The documentation above leads me to expect the symmetric behavior for set fo=ta, where no automatic formatting is done within comments, but the rest of the text reflows automatically. The example above shows that the behavior is not symmetric the way the documentation suggests, unless I'm misunderstanding the documentation.

One reason I want to use set fo=ta is for editing Markdown files--if it worked the way I expected, I could set the comments option so that code blocks are considered as comments. Then I could get automatic formatting in most of the file, yet avoid automatic formatting within code blocks.

[brammool]

Note: I originally filed this as a neovim issue [here](neovim/neovim#9422). It was suggested on the #neovim IRC channel to also post this here. - Version: 8.1.146 (also affects neovim 0.3.1) - Operating system/version: NixOS 18.09 - Terminal name/version: st-0.8.1 - `$TERM`: st-256color ### Steps to reproduce using `vim -u NONE` ``` vim -u NONE :set fo=ta<cr>i% test<cr>% test ``` ### Actual behaviour On typing the second '%', autoformatting kicks in, and the two lines are combined into one. The final result is a single line: ``` % test % test ``` ### Expected behaviour Since `:set comments` gives a string including ":%", I expect that when I type the second '%', vim recognizes the second line as a comment and does not combine the two lines into one, since `formatoptions` does not include the `c` flag. My expected final result is: ``` % test % test ``` ### Explanation The documentation for `fo-table` says: > With 't' and 'c' you can specify when Vim performs auto-wrapping: > value action > "" no automatic formatting (you can use "gq" for manual formatting) > "t" automatic formatting of text, but not comments > "c" automatic formatting for comments, but not text (good for C code) > "tc" automatic formatting for text and comments When we use `set fo=ca`, we get the nice behavior where no automatic formatting is done outside of comments, but comments reflow automatically. The documentation above leads me to expect the symmetric behavior for `set fo=ta`, where no automatic formatting is done within comments, but the rest of the text reflows automatically. The example above shows that the behavior is not symmetric the way the documentation suggests, unless I'm misunderstanding the documentation. One reason I want to use `set fo=ta` is for editing Markdown files--if it worked the way I expected, I could set the `comments` option so that code blocks are considered as comments. Then I could get automatic formatting in most of the file, yet avoid automatic formatting within code blocks.

There two separate functions: Breaking a line when it gets too long, and reformatting a paragraph whenever text is changed inside it. Without the "c" flag the breaking of long text doesn't happen in comments. With the "c" flag paragraphs are only auto-formatted if they are recognized as comments. There currently is no way to specify that auto-formatting ONLY applies to commengs. The current behavior was done because it seemd like the most useful way (auto-formatting comments in a code file), but it is inconsistent. This would require a new flag, which would do the opposite of what "c" does in "ca". I suppose we could use the capital "C" for that.

…

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[msuperdock]

Thanks for the explanation--the behavior makes more sense to me now. I personally would like having an additional flag, but I think it would also be reasonable for you to decide that this use case isn't common enough to warrant adding more code.

Maybe the fo-table documentation could be changed to make it more clear that there are two pieces of functionality at work here? I would be happy to draft a documentation change if you'd like.