~ / neovim / comment-lineslesson 3/7

Comment lines: gcc and gc{motion}

Toggle comments with the built-in gc operator.

?how it works

Neovim comments code out of the box. gcc toggles the current line, and gc is an operator, so it takes any motion or text object: gcj (this line and the next), gc3j, gcip (the paragraph), gcG (to the end of the file). A count works on gcc too: 3gcc.

The marker comes from 'commentstring', which the filetype sets: # %s for Python and shell, -- %s for Lua, // %s for JavaScript. Each drill here tells the editor which language it is.

The rules, in short:

If every non-blank line in the range is already a comment, gc uncomments them. Otherwise it comments all of them, and lines that were already comments get a second marker.
Markers line up with the least indented line, so the code keeps its shape.
Blank lines inside a multi-line range get a bare marker.

gc is an operator, so . repeats it.

Mnemonic: go comment. Doubling the last letter means "this line", just like dd and yy.

⌨keys

`gcc`	toggle comments on [count] linesnvim
`gc{motion}`	toggle comments on the lines {motion} coversnvim
`{Visual}gc`	toggle comments on the selected linesnvim
`.`	repeat the last gc

Nin neovim

Built-in commenting arrived in Neovim 0.10 (:h commenting). With a treesitter parser installed, code embedded in another language (say, Lua inside Markdown) gets the marker for its own language.

4 drills

One line with gcc: Toggle the comment on the cursor line with gcc: comment it out, or bring it back if it's already a comment.
Several lines with gc{motion}: Comment out the lines shown in the target with one gc command: the operator plus a motion or text object.
Blocks that already have comments: Comment out the whole block in one go. Existing comments get a second //, and empty lines inside the range get a bare //.
Toggle again with .: Toggle the two places shown in the target. Do the first with gc, move, and repeat it with ..

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