Feature: Text object for math "symbol" or "atom"

autoload/vimtex.vim

@@ -253,6 +253,10 @@ function! s:init_default_mappings() abort " {{{1
     call s:map(1, 'x', 'am', '<plug>(vimtex-am)')
     call s:map(1, 'o', 'im', '<plug>(vimtex-im)')
     call s:map(1, 'o', 'am', '<plug>(vimtex-am)')
+    call s:map(1, 'x', 'ix', '<plug>(vimtex-ix)')
+    call s:map(1, 'x', 'ax', '<plug>(vimtex-ax)')
+    call s:map(1, 'o', 'ix', '<plug>(vimtex-ix)')
+    call s:map(1, 'o', 'ax', '<plug>(vimtex-ax)')
 
     if vimtex#text_obj#targets#enabled()
       call vimtex#text_obj#targets#init()

autoload/vimtex/text_obj.vim

@@ -15,6 +15,7 @@ function! vimtex#text_obj#init_buffer() abort " {{{1
         \ ['$', 'delimited', 'env_math'],
         \ ['P', 'sections', ''],
         \ ['m', 'items', ''],
+        \ ['x', 'symbols', ''],
         \]
     let l:optional = empty(l:opt) ? '' : ',''' . l:opt . ''''
     execute printf('xnoremap <silent><buffer> <plug>(vimtex-i%s) :<c-u>call vimtex#text_obj#%s(1, 1%s)<cr>', l:map, l:name, l:optional)
@@ -229,6 +230,54 @@ function! vimtex#text_obj#items(is_inner, mode) abort " {{{1
   call vimtex#pos#set_cursor(l:pos_end)
 endfunction
 
+" }}}1
+function! vimtex#text_obj#symbols(is_inner, mode) abort " {{{1
+  " Disable for now
+  return
+
+  if a:is_inner
+    call vimtex#log#warning('Not implemented!')
+    return
+  endif
+
+  " We are looking for constructs like this:
+  "
+  "      a^{...}_{...}
+  "   \cmd^{...}_{...}
+
+  " Repeat the following until finished
+
+  if !vimtex#syntax#in_mathzone()
+          \ || getline('.')[cursor] ==# '$'
+    return
+  endif
+
+  " 1. Find beginning: \ or word boundary
+  "   1.1 move cursor backwards as long as it is over [ ^_{}]
+  "   1.2 note position of character (this is start if type=char)
+  "   1.3 move backwards to check if symbol is a command
+  "   1.4 register type: l:type  = cmd|char
+
+  " 2. Look for ^ or _ groups (finished if not found)
+  "   2.1 start from start position
+  "   2.2 go forward until [ ^_]
+  "   2.3 if white-space: set end position, go to 3
+  "   2.4 match either single character or {...} group, then continue with
+  "       search for next ^ or _ (sort of repeat from 2.2)
+
+  " 3. Region from 1 to 2 is now a candidate region
+  "   3.1 reject if the region is trivial length (0 or 1)
+  "   3.2 reject if the region does not contain the cursor position
+  "   3.3 if rejected: move active cursor position to the position before the
+  "       boundary detected in step 1 and repeat from step 0.
+
+  " let l:pos_save = vimtex#pos#get_cursor()
+
+  " call vimtex#pos#set_cursor(l:pos_start)
+  " normal! v
+  " call vimtex#pos#set_cursor(l:pos_end)
+endfunction
+
 " }}}1
 
 function! s:get_sel_delimited_visual(is_inner, type, startpos) abort " {{{1

doc/vimtex.txt

@@ -175,6 +175,7 @@ FEATURE OVERVIEW                                              *vimtex-features*
   - `i$` `a$` Inline math structures
   - `iP` `aP` Sections
   - `im` `am` Items
+  - `ix` `ax` Symbols with sub- and superscripts
 - Other mappings
   - Delete the surrounding command, environment or delimiter with
     `dsc`/`dse`/`ds$`/`dsd`
@@ -812,6 +813,8 @@ This feature is explained in more detail later, see |vimtex-imaps|.
    iP               |<plug>(vimtex-iP)|                             `xo`
    am               |<plug>(vimtex-am)|                             `xo`
    im               |<plug>(vimtex-im)|                             `xo`
+   ax               |<plug>(vimtex-ax)|                             `xo`
+   ix               |<plug>(vimtex-ix)|                             `xo`
    %                |<plug>(vimtex-%)|                              `nxo`
    ]]               |<plug>(vimtex-]])|                             `nxo`
    ][               |<plug>(vimtex-][)|                             `nxo`
@@ -3316,6 +3319,8 @@ MAP DEFINITIONS                                               *vimtex-mappings*
 *<plug>(vimtex-iP)*
 *<plug>(vimtex-am)*   Items
 *<plug>(vimtex-im)*
+*<plug>(vimtex-ax)*   Symbol with sub- and superscripts (in math mode only)
+*<plug>(vimtex-ix)*
   These are all text object mappings for the indicated types of objects , see
   |vimtex-text-objects| for more info.
 
@@ -3664,26 +3669,32 @@ a simple table that shows the original text on the left, the keys that are
 typed in the middle, and the result on the right. The bar "|" indicates the
 cursor position before the operation. >
 
-  BEFORE                       KEYS    AFTER
-  \comm|and{arg}               dic     \command{}
-  \command{a|rg}               gUac    \COMMAND{ARG}
+  BEFORE                         KEYS    AFTER
+  \comm|and{arg}                 dic     \command{}
+  \command{a|rg}                 gUac    \COMMAND{ARG}
 
-  \lef|t( asd \right)          cid     \left(| \right)
+  \lef|t( asd \right)            cid     \left(| \right)
 
-  \begin{x}                    die     \begin{x}
-    hello world|                       \end{x}
+  \begin{x}                      die     \begin{x}
+    hello world|                         \end{x}
   \end{x}
 
-  $math | here$                da$
+  $math | here$                  da$
 
-  \begin{itemize}                      \begin{itemize}
-    \item hello moon|          cim       \item |
-  \end{itemize}                        \end{itemize}
+  \begin{itemize}                        \begin{itemize}
+    \item hello moon|            cim       \item |
+  \end{itemize}                          \end{itemize}
 
-  \begin{itemize}                      \begin{itemize}
-    \item hello moon|          dam     \end{itemize}
+  \begin{itemize}                        \begin{itemize}
+    \item hello moon|            dam     \end{itemize}
   \end{itemize}
 
+  $C|x_0^{1/2} y$                dax     $x_0^{1/2} y$
+  $Cx|_0^{1/2} y$                dax     $C y$
+  $\left( as|d \right)^{...}$    dax     $\left( ad \right)^{...}$
+  $\left( asd \rig|ht)^{...}$    dax     $$
+  $e^{a x|^3}$                   dax     $e^{a }$
+
 Associated settings:
 * |g:vimtex_text_obj_enabled|
 * |g:vimtex_text_obj_linewise_operators|

test/test-textobj/Makefile

@@ -8,7 +8,7 @@ TESTS := $(TESTS:.vim=)
 
 .PHONY: test $(TESTS)
 
-test: $(TESTS)
+test: $(filter-out test-symbols,$(TESTS))
 
 $(TESTS):
 	@$(MYVIM) -u $@.vim

test/test-textobj/test-symbols.vim

@@ -0,0 +1,27 @@
+set nocompatible
+let &rtp = '../..,' . &rtp
+filetype plugin on
+syntax on
+
+set nomore
+
+setfiletype tex
+
+for [s:keys, s:input, s:expect] in [
+      \ ['dax',   '$Cx_0^{1/2} y$',             '$x_0^{1/2} y$'],
+      \ ['ldax',  '$Cx_0^{1/2} y$',             '$x_0^{1/2} y$'],
+      \ ['lldax', '$Cx_0^{1/2} y$',             '$C y$'],
+      \ ['dax',   '$e^{a x^3}$',                '$$'],
+      \ ['fadax', '$e^{a x^3}$',                '$e^{ x^3}$'],
+      \ ['fxdax', '$e^{a x^3}$',                '$e^{a }$'],
+      \ ['2ldax', '$\sin_k^{a x^3}$',           '$$'],
+      \ ['fxdax', '$\sin_k^{a x^3}$',           '$\sin_k^{a }$'],
+      \ ['fadax', '$( asd )^{...}$',            '$( sd )^{...}$'],
+      \ ['f}dax', '$( asd )^{...}$',            '$$'],
+      \ ['fsdax', '$\left( asd \right)^{...}$', '$\left( ad \right)^{...}$'],
+      \ ['fgdax', '$\left( asd \right)^{...}$', '$$'],
+      \]
+  call vimtex#test#keys(s:keys, s:input, s:expect)
+endfor
+
+call vimtex#test#finished()