Resolve syntax highlighting group in neovim/treesitter (#160)

Co-authored-by: Junegunn Choi <junegunn.c@gmail.com>

README.md

@@ -406,7 +406,7 @@ highlighted as code comments or strings are ignored.
 ```vim
 " Default:
 "   If a delimiter is in a highlight group whose name matches
-"   any of the followings, it will be ignored.
+"   any of the following regular expressions, it will be ignored.
 let g:easy_align_ignore_groups = ['Comment', 'String']
 ```
 
@@ -463,6 +463,19 @@ If a pattern in `ignore_groups` is prepended by a `!`, it will have the opposite
 meaning. For instance, if `ignore_groups` is given as `['!Comment']`, delimiters
 that are *not* highlighted as Comment will be ignored during the alignment.
 
+To make `ignore_groups` work, and to debug the related issues, it is useful to
+know which highlight group a certain location in a file belongs to. A special
+function exists for this purpose, returning exactly the name of the highlight
+group that is used by the easy align plugin.
+
+```vim
+" Highlight group name of the cursor position
+echo easy_align#get_highlight_group_name()
+
+" Highlight group name of the line 10, column 20
+echo easy_align#get_highlight_group_name(10, 20)
+```
+
 ### Ignoring unmatched lines
 
 `ignore_unmatched` option determines how EasyAlign command processes lines that

autoload/easy_align.vim

@@ -89,9 +89,30 @@ function! s:floor2(v)
   return a:v % 2 == 0 ? a:v : a:v - 1
 endfunction
 
+function! s:get_highlight_group_name(line, col)
+  let hl = synIDattr(synID(a:line, a:col, 0), 'name')
+
+  if hl == '' && has('nvim-0.9.0')
+    let insp = luaeval('vim.inspect_pos and vim.inspect_pos( nil, ' .. (a:line-1) .. ', ' .. (a:col-1) .. ' ) or { treesitter = {} }')
+    if !empty(insp.treesitter)
+      let hl = insp.treesitter[0].hl_group_link
+    endif
+  endif
+
+  " and, finally
+  return hl
+endfunction
+
+function! easy_align#get_highlight_group_name(...)
+  let l  = get(a:, 1, line('.'))
+  let c  = get(a:, 2, col('.'))
+  let hl = s:get_highlight_group_name(l, c)
+  return { 'line': l, 'column': c, 'group': hl }
+endfunction
+
 function! s:highlighted_as(line, col, groups)
   if empty(a:groups) | return 0 | endif
-  let hl = synIDattr(synID(a:line, a:col, 0), 'name')
+  let hl = s:get_highlight_group_name(a:line, a:col)
   for grp in a:groups
     if grp[0] == '!'
       if hl !~# grp[1:-1]
@@ -731,16 +752,16 @@ function! s:interactive(range, modes, n, d, opts, rules, vis, bvis)
       else
         let s:live = 1
       endif
-    elseif c == "\<Left>"  || ch == "h"
+    elseif c == "\<Left>"
       let opts['stl'] = 1
       let opts['lm']  = 0
-    elseif c == "\<Right>" || ch == "l"
+    elseif c == "\<Right>"
       let opts['stl'] = 0
       let opts['lm']  = 1
-    elseif c == "\<Down>"  || ch == "j"
+    elseif c == "\<Down>"
       let opts['lm']  = 0
       let opts['rm']  = 0
-    elseif c == "\<Up>"    || ch == "k"
+    elseif c == "\<Up>"
       silent! call remove(opts, 'stl')
       silent! call remove(opts, 'lm')
       silent! call remove(opts, 'rm')
@@ -1146,3 +1167,4 @@ endfunction
 let &cpo = s:cpo_save
 unlet s:cpo_save
 
+" vim: set et sw=2 :

doc/easy_align.txt

@@ -279,7 +279,7 @@ to align text around all occurrences of numbers:
  - <Enter>
  - `*`
  - CTRL-X
- - `[0-9]\+`
+   - `[0-9]\+`
 
 
 Alignment options in interactive mode~
@@ -290,27 +290,21 @@ While in interactive mode, you can set alignment options using special
 shortcut keys listed below. The meaning of each option will be described in
 {the following sections}{6}.
 
- --------+----------------------+---------------------------------------------
- Key     |  Option              | Values                                            ~
- --------+----------------------+---------------------------------------------
- CTRL-F  | `filter`               | Input string ( `[gv]/.*/?` )
- CTRL-I  | `indentation`          | shallow, deep, none, keep
- CTRL-L  | `left_margin`          | Input number or string
- CTRL-R  | `right_margin`         | Input number or string
- CTRL-D  | `delimiter_align`      | left, center, right
- CTRL-U  | `ignore_unmatched`     | 0, 1
- CTRL-G  | `ignore_groups`        | [], ["String'], ["Comment'],
-         |                      | ["String', "Comment']
- CTRL-A  | `align`                | Input string ( `/[lrc]+\*{0,2}/` )
- <Left>  | `stick_to_left`        | `{ 'left_margin': 0, 'stick_to_left': 1 }`
- h       | `stick_to_left`        | `{ 'left_margin': 0, 'stick_to_left': 1 }`
- <Right> | `stick_to_left`        | `{ 'left_margin': 1, 'stick_to_left': 0 }`
- l       | `stick_to_left`        | `{ 'left_margin': 1, 'stick_to_left': 0 }`
- <Down>  | `*_margin`             | `{ 'left_margin': 0, 'right_margin':  0 }`
- j       | `*_margin`             | `{ 'left_margin': 0, 'right_margin':  0 }`
- <Up>    | `reset_stl_and_margin` | `{ 'left_margin': 1, 'right_margin':  1 }`
- k       | `reset_stl_and_margin` | `{ 'left_margin': 1, 'right_margin':  1 }`
- --------+----------------------+---------------------------------------------
+ --------+--------------------+---------------------------------------------------
+ Key     | Option             | Values                                            ~
+ --------+--------------------+---------------------------------------------------
+ CTRL-F  |  `filter`            | Input string ( `[gv]/.*/?` )
+ CTRL-I  |  `indentation`       | shallow, deep, none, keep
+ CTRL-L  |  `left_margin`       | Input number or string
+ CTRL-R  |  `right_margin`      | Input number or string
+ CTRL-D  |  `delimiter_align`   | left, center, right
+ CTRL-U  |  `ignore_unmatched`  | 0, 1
+ CTRL-G  |  `ignore_groups`     | [], ["String'], ["Comment'], ["String', "Comment']
+ CTRL-A  |  `align`             | Input string ( `/[lrc]+\*{0,2}/` )
+ <Left>  |  `stick_to_left`     |  `{ 'stick_to_left': 1, 'left_margin': 0 }`
+ <Right> |  `stick_to_left`     |  `{ 'stick_to_left': 0, 'left_margin': 1 }`
+ <Down>  |  `*_margin`          |  `{ 'left_margin': 0, 'right_margin': 0 }`
+ --------+--------------------+---------------------------------------------------
 
               {6} https://github.com/junegunn/vim-easy-align#alignment-options
 
@@ -523,7 +517,7 @@ highlighted as code comments or strings are ignored.
 >
     " Default:
     "   If a delimiter is in a highlight group whose name matches
-    "   any of the followings, it will be ignored.
+    "   any of the following regular expressions, it will be ignored.
     let g:easy_align_ignore_groups = ['Comment', 'String']
 <
 For example, the following paragraph
@@ -573,6 +567,17 @@ opposite meaning. For instance, if `ignore_groups` is given as `['!Comment']`,
 delimiters that are not highlighted as Comment will be ignored during the
 alignment.
 
+To make `ignore_groups` work, and to debug the related issues, it is useful to
+know which highlight group a certain location in a file belongs to. A special
+function exists for this purpose, returning exactly the name of the highlight
+group that is used by the easy align plugin.
+>
+    " Highlight group name of the cursor position
+    echo easy_align#get_highlight_group_name()
+
+    " Highlight group name of the line 10, column 20
+    echo easy_align#get_highlight_group_name(10, 20)
+<
 
 < Ignoring unmatched lines >__________________________________________________~
                                            *easy-align-ignoring-unmatched-lines*

plugin/easy_align.vim

@@ -140,3 +140,4 @@ vnoremap <silent> <Plug>(EasyAlignRepeat) :<C-U>call <SID>repeat_in_visual()<Ent
 " Backward-compatibility (deprecated)
 nnoremap <silent> <Plug>(EasyAlignOperator) :set opfunc=<SID>easy_align_op<Enter>g@
 
+" vim: set et sw=2 :