feat: auto calculate commentstring (#62)

Adding basic support of treesitter for calculating `commentstring` which works most of the time and might be all that someone needs. But due to the nature of the parsed tree, this implementation has some known limitations.

1. No `jsx/tsx` support. Its implementation was quite complicated.
2. Invalid comment on the region where one language ends and the other starts. See #62 (comment)

For more advance use cases you should use https://github.com/JoosepAlviste/nvim-ts-context-commentstring. See hooks section.

Author: tjdevries

README.md

@@ -5,20 +5,20 @@
 
 ### ✨ Features
 
--   Supports `commentstring`. [Read more](#commentstring)
--   Prefers single-line/linewise comments
--   Supports line (`//`) and block (`/* */`) comments
--   Dot (`.`) repeat support for `gcc`, `gbc` and friends
--   Count support (`[count]gcc` only)
--   Left-right (`gcw` `gc$`) and Up-Down (`gc2j` `gc4k`) motions
--   Use with text-objects (`gci{` `gbat`)
--   Supports pre and post hooks
--   Custom language/filetype support
--   Ignore certain lines, powered by Lua regex
+- Supports treesitter. [Read more](#treesitter)
+- Supports `commentstring`. [Read more](#commentstring)
+- Prefers single-line/linewise comments
+- Supports line (`//`) and block (`/* */`) comments
+- Dot (`.`) repeat support for `gcc`, `gbc` and friends
+- Count support (`[count]gcc` only)
+- Left-right (`gcw` `gc$`) and Up-Down (`gc2j` `gc4k`) motions
+- Use with text-objects (`gci{` `gbat`)
+- Supports pre and post hooks
+- Ignore certain lines, powered by Lua regex
 
 ### 🚀 Installation
 
--   With [packer.nvim](https://github.com/wbthomason/packer.nvim)
+- With [packer.nvim](https://github.com/wbthomason/packer.nvim)
 
 ```lua
 use {
@@ -29,7 +29,7 @@ use {
 }
 ```
 
--   With [vim-plug](https://github.com/junegunn/vim-plug)
+- With [vim-plug](https://github.com/junegunn/vim-plug)
 
 ```vim
 Plug 'numToStr/Comment.nvim'
@@ -44,13 +44,13 @@ lua require('Comment').setup()
 
 First you need to call the `setup()` method to create the default mappings.
 
--   Lua
+- Lua
 
 ```lua
 require('Comment').setup()
 ```
 
--   VimL
+- VimL
 
 ```vim
 lua << EOF
@@ -138,7 +138,7 @@ When you call [`setup()`](#setup) method, `Comment.nvim` sets up some basic mapp
 
 These mappings are enabled by default. (config: `mappings.basic`)
 
--   NORMAL mode
+- NORMAL mode
 
 ```help
 `gcc` - Toggles the current line using linewise comment
@@ -152,7 +152,7 @@ These mappings are enabled by default. (config: `mappings.basic`)
 
 > NOTE: Dot repeat is not supported with `[count]gcc`
 
--   VISUAL mode
+- VISUAL mode
 
 ```help
 `gc` - Toggles the region using linewise comment
@@ -163,7 +163,7 @@ These mappings are enabled by default. (config: `mappings.basic`)
 
 These mappings are enabled by default. (config: `mappings.extra`)
 
--   NORMAL mode
+- NORMAL mode
 
 ```help
 `gco` - Insert comment to the next line and enters INSERT mode
@@ -175,7 +175,7 @@ These mappings are enabled by default. (config: `mappings.extra`)
 
 These mappings are disabled by default. (config: `mappings.extended`)
 
--   NORMAL mode
+- NORMAL mode
 
 ```help
 `g>[count]{motion}` - (Op-pending) Comments the region using linewise comment
@@ -186,7 +186,7 @@ These mappings are disabled by default. (config: `mappings.extended`)
 `g<b`- Uncomments the current line using blockwise comment
 ```
 
--   VISUAL mode
+- VISUAL mode
 
 ```help
 `g>` - Comments the region using single line
@@ -234,13 +234,24 @@ require('Comment').toggle()
 
 Read [API](./API.md) for more crazy stuff.
 
+<a id="treesitter"></a>
+
+### 🌳 Treesitter
+
+This plugin also has the basic support of treesitter for calculating `commentstring` which works most of the time and might be all that someone needs. But due to the nature of the parsed tree, this implementation has some known limitations.
+
+1. No `jsx/tsx` support. Its implementation was quite complicated.
+2. Invalid comment on the region where one language ends and the other starts. [Read more](https://github.com/numToStr/Comment.nvim/pull/62#issuecomment-972790418)
+
+For more advance use cases you should use [nvim-ts-context-commentstring](https://github.com/JoosepAlviste/nvim-ts-context-commentstring). See [hooks](#hooks) section.
+
 <a id="hooks"></a>
 
 ### 🎣 Hooks
 
 There are two hook methods i.e `pre_hook` and `post_hook` which are called before comment and after comment respectively. Both should be provided during [`setup()`](#setup).
 
--   `pre_hook` - This method is called with a [`ctx`](#comment-context) argument before comment/uncomment is started. It can be used to return a custom `commentstring` which will be used for comment/uncomment the lines. You can use something like [nvim-ts-context-commentstring](https://github.com/JoosepAlviste/nvim-ts-context-commentstring) to compute the commentstring using treesitter.
+- `pre_hook` - This method is called with a [`ctx`](#comment-context) argument before comment/uncomment is started. It can be used to return a custom `commentstring` which will be used for comment/uncomment the lines. You can use something like [nvim-ts-context-commentstring](https://github.com/JoosepAlviste/nvim-ts-context-commentstring) to compute the commentstring using treesitter.
 
 ```lua
 -- NOTE: The example below is a proper integration and it is RECOMMENDED.
@@ -285,7 +296,7 @@ Also, you can set the `commentstring` from here but [**i won't recommend it**](#
 }
 ```
 
--   `post_hook` - This method is called after commenting is done. It receives the same 1) [`ctx`](#comment-context), the lines range 2) `start_row` 3) `end_row` 4) `start_col` 5) `end_col`.
+- `post_hook` - This method is called after commenting is done. It receives the same 1) [`ctx`](#comment-context), the lines range 2) `start_row` 3) `end_row` 4) `start_col` 5) `end_col`.
 
 > NOTE: If [methods](#methods) are used, then `post_hook` will receives only two arguments 1) [`ctx`](#comment-context) and 2) `-1` indicating the current line
 
@@ -316,7 +327,7 @@ You can use `ignore` to ignore certain lines during comment/uncomment. It can ta
 
 > NOTE: Ignore only works when with linewise comment. This is by design. As ignoring lines in block comments doesn't make that much sense.
 
--   With `string`
+- With `string`
 
 ```lua
 -- ignores empty lines
@@ -329,7 +340,7 @@ ignore = '^(%s*)local'
 ignore = '^const(.*)=(%s?)%((.*)%)(%s?)=>'
 ```
 
--   With `function`
+- With `function`
 
 ```lua
 {
@@ -391,11 +402,11 @@ ft({'toml', 'graphql'}, '#%s')
 
 Although, `Comment.nvim` supports neovim's `commentstring` but unfortunately it has the least priority. The commentstring is taken from the following place in the respective order.
 
--   [`pre_hook`](#hooks) - If a string is returned from this method then it will be used for commenting.
+- [`pre_hook`](#hooks) - If a string is returned from this method then it will be used for commenting.
 
--   [`ft_table`](#languages) - If the current filetype is found in the table, then the string there will be used.
+- [`ft_table`](#languages) - If the current filetype is found in the table, then the string there will be used.
 
--   `commentstring` - Neovim's native commentstring for the filetype
+- `commentstring` - Neovim's native commentstring for the filetype
 
 <a id="commentstring-caveat"></a>
 
@@ -412,6 +423,7 @@ The following object is provided as an argument to `pre_hook` and `post_hook` fu
 ```lua
 ---Comment context
 ---@class Ctx
+---@field lang string: The name of the language where the cursor is
 ---@field ctype CType
 ---@field cmode CMode
 ---@field cmotion CMotion
@@ -433,27 +445,14 @@ There are multiple ways to contribute reporting/fixing bugs, feature requests. Y
 
 ### 💐 Credits
 
--   [tcomment]() - To be with me forever and motivated me to write this.
--   [nvim-comment](https://github.com/terrortylor/nvim-comment) - Little and less powerful cousin. Also I took some code from it.
--   [kommentary](https://github.com/b3nj5m1n/kommentary) - Nicely done plugin but lacks some features. But it helped me to design this plugin.
+- [tcomment]() - To be with me forever and motivated me to write this.
+- [nvim-comment](https://github.com/terrortylor/nvim-comment) - Little and less powerful cousin. Also I took some code from it.
+- [kommentary](https://github.com/b3nj5m1n/kommentary) - Nicely done plugin but lacks some features. But it helped me to design this plugin.
 
 ### 🚗 Roadmap
 
--   Live upto the expectation of `tcomment`
--   Basic INSERT mode mappings
--   Doc comment i.e `/**%s*/` (js), `///%s` (rust)
-
--   Inbuilt context commentstring using treesitter
-
-```lua
-{
-    pre_hook = function()
-        return require('Comment.ts').commentstring()
-    end
-}
-```
-
--   Header comment
+- Doc comment i.e `/**%s*/` (js), `///%s` (rust)
+- Header comment
 
 ```lua
 ----------------------

lua/Comment/comment.lua

@@ -7,27 +7,23 @@ local C = {
     config = nil,
 }
 
----Comment context
----@class Ctx
----@field ctype CType
----@field cmode CMode
----@field cmotion CMotion
-
 ---Comments the current line
 function C.comment()
     local line = A.nvim_get_current_line()
 
     local pattern = U.get_pattern(C.config.ignore)
     if not U.ignore(line, pattern) then
+        local srow, scol = unpack(A.nvim_win_get_cursor(0))
         ---@type Ctx
         local ctx = {
             cmode = U.cmode.comment,
             cmotion = U.cmotion.line,
             ctype = U.ctype.line,
+            range = { srow = srow, scol = scol, erow = srow, ecol = scol },
         }
+        local lcs, rcs = U.parse_cstr(C.config, ctx)
 
         local padding, _ = U.get_padding(C.config.padding)
-        local lcs, rcs = U.parse_cstr(C.config, ctx)
         A.nvim_set_current_line(U.comment_str(line, lcs, rcs, padding))
         U.is_fn(C.config.post_hook, ctx, -1)
     end
@@ -39,14 +35,16 @@ function C.uncomment()
 
     local pattern = U.get_pattern(C.config.ignore)
     if not U.ignore(line, pattern) then
+        local srow, scol = unpack(A.nvim_win_get_cursor(0))
         ---@type Ctx
         local ctx = {
             cmode = U.cmode.uncomment,
             cmotion = U.cmotion.line,
             ctype = U.ctype.line,
+            range = { srow = srow, scol = scol, erow = srow, ecol = scol },
         }
-
         local lcs, rcs = U.parse_cstr(C.config, ctx)
+
         local _, pp = U.get_padding(C.config.padding)
         local lcs_esc, rcs_esc = U.escape(lcs), U.escape(rcs)
 
@@ -64,14 +62,16 @@ function C.toggle()
 
     local pattern = U.get_pattern(C.config.ignore)
     if not U.ignore(line, pattern) then
+        local srow, scol = unpack(A.nvim_win_get_cursor(0))
         ---@type Ctx
         local ctx = {
             cmode = U.cmode.toggle,
             cmotion = U.cmotion.line,
             ctype = U.ctype.line,
+            range = { srow = srow, scol = scol, erow = srow, ecol = scol },
         }
-
         local lcs, rcs = U.parse_cstr(C.config, ctx)
+
         local lcs_esc, rcs_esc = U.escape(lcs), U.escape(rcs)
         local padding, pp = U.get_padding(C.config.padding)
         local is_cmt = U.is_commented(lcs_esc, rcs_esc, pp)(line)

lua/Comment/extra.lua

@@ -7,29 +7,31 @@ local E = {}
 ---@param ctype CType
 ---@param cfg Config
 local function ins_on_line(count, ctype, cfg)
+    local row, col = unpack(A.nvim_win_get_cursor(0))
+
     ---@type Ctx
     local ctx = {
         cmode = U.cmode.comment,
         cmotion = U.cmotion.line,
         ctype = ctype,
+        range = { srow = row, scol = col, erow = row, ecol = col },
     }
+    local lcs, rcs = U.parse_cstr(cfg, ctx)
 
-    local pos = A.nvim_win_get_cursor(0)
-    local srow, scol = pos[1] + count, pos[2]
     local line = A.nvim_get_current_line()
     local indent = U.grab_indent(line)
-    local lcs, rcs = U.parse_cstr(cfg, ctx)
     local padding = U.get_padding(cfg.padding)
 
     -- We need RHS of cstr, if we are doing block comments or if RHS exists
     -- because even in line comment RHS do exists for some filetypes like jsx_element, ocaml
     local if_rcs = (ctype == U.ctype.block or rcs) and padding .. rcs or ''
 
+    local srow = row + count
     local ll = indent .. lcs .. padding
     A.nvim_buf_set_lines(0, srow, srow, false, { ll .. if_rcs })
     local erow, ecol = srow + 1, #ll - 1
     U.move_n_insert(erow, ecol)
-    U.is_fn(cfg.post_hook, ctx, srow, erow, scol, ecol)
+    U.is_fn(cfg.post_hook, ctx, srow, erow, col, ecol)
 end
 
 ---Add a comment below the current line and goes to INSERT mode
@@ -50,16 +52,18 @@ end
 ---@param ctype CType
 ---@param cfg Config
 function E.norm_A(ctype, cfg)
+    local srow, scol = unpack(A.nvim_win_get_cursor(0))
+
     ---@type Ctx
     local ctx = {
         cmode = U.cmode.comment,
         cmotion = U.cmotion.line,
         ctype = ctype,
+        range = { srow = srow, scol = scol, erow = srow, ecol = scol },
     }
+    local lcs, rcs = U.parse_cstr(cfg, ctx)
 
-    local pos = A.nvim_win_get_cursor(0)
     local line = A.nvim_get_current_line()
-    local lcs, rcs = U.parse_cstr(cfg, ctx)
     local padding = U.get_padding(cfg.padding)
 
     -- NOTE:
@@ -72,7 +76,6 @@ function E.norm_A(ctype, cfg)
     -- because even in line comment RHS do exists for some filetypes like jsx_element, ocaml
     local if_rcs = (ctype == U.ctype.block or rcs) and padding .. rcs or ''
 
-    local srow, scol = pos[1], pos[2]
     local erow, ecol = srow - 1, #ll - 1
     A.nvim_buf_set_lines(0, erow, srow, false, { ll .. if_rcs })
     U.move_n_insert(srow, ecol)