feat(extmarks,ts,spell): full support for spelling

- Added 'spell' option to extmarks:

  Extmarks with this set will have the region spellchecked.

- Added 'noplainbuffer' option to 'spelloptions':

  This is used to tell Neovim not to spellcheck the buffer. The old
  behaviour was to spell check the whole buffer unless :syntax was set.

- Added spelling support to the treesitter highlighter:

  @spell captures in highlights.scm are used to define regions which
  should be spell checked.

- Added support for navigating spell errors for extmarks:

  Works for both ephemeral and static extmarks

- Added '_on_spell_nav' callback for decoration providers:

  Since ephemeral callbacks are only drawn for the visible screen,
  providers must implement this callback to instruct Neovim which
  regions in the buffer need can be spell checked.

  The callback takes a start position and an end position.

  Note: this callback is subject to change hence the _ prefix.

- Added spell captures for built-in support languages

Co-authored-by: Lewis Russell <lewis6991@gmail.com>
Co-authored-by: Björn Linse <bjorn.linse@gmail.com>

1 files changed, 63 insertions, 21 deletions

diff --git a/src/nvim/spell.c b/src/nvim/spell.c
index c0d05eb799..30e256b37a 100644
--- a/src/nvim/spell.c
+++ b/src/nvim/spell.c
@@ -71,6 +71,7 @@
 #include "nvim/change.h"          // for changed_bytes
 #include "nvim/charset.h"         // for skipwhite, getwhitecols, skipbin
 #include "nvim/cursor.h"          // for get_cursor_line_ptr
+#include "nvim/decoration.h"
 #include "nvim/drawscreen.h"      // for NOT_VALID, redraw_later
 #include "nvim/eval/typval.h"     // for semsg
 #include "nvim/ex_cmds.h"         // for do_sub_msg
@@ -220,7 +221,7 @@ size_t spell_check(win_T *wp, char_u *ptr, hlf_T *attrp, int *capcol, bool docou
   size_t nrlen = 0;              // found a number first
   size_t wrongcaplen = 0;
   bool count_word = docount;
-  bool use_camel_case = *wp->w_s->b_p_spo != NUL;
+  bool use_camel_case = (wp->w_s->b_p_spo_flags & SPO_CAMEL) != 0;
   bool camel_case = false;
 
   // A word never starts at a space or a control character. Return quickly
@@ -1198,6 +1199,24 @@ bool no_spell_checking(win_T *wp)
   return false;
 }
 
+static void decor_spell_nav_start(win_T *wp)
+{
+  decor_state = (DecorState){ 0 };
+  decor_redraw_reset(wp->w_buffer, &decor_state);
+}
+
+static bool decor_spell_nav_col(win_T *wp, linenr_T lnum, linenr_T *decor_lnum, int col,
+                                char **decor_error)
+{
+  if (*decor_lnum != lnum) {
+    decor_providers_invoke_spell(wp, lnum - 1, col, lnum - 1, -1, decor_error);
+    decor_redraw_line(wp->w_buffer, lnum - 1, &decor_state);
+    *decor_lnum = lnum;
+  }
+  decor_redraw_col(wp->w_buffer, col, col, false, &decor_state);
+  return decor_state.spell;
+}
+
 /// Moves to the next spell error.
 /// "curline" is false for "[s", "]s", "[S" and "]S".
 /// "curline" is true to find word under/after cursor in the same line.
@@ -1216,11 +1235,11 @@ size_t spell_move_to(win_T *wp, int dir, bool allwords, bool curline, hlf_T *att
   hlf_T attr = HLF_COUNT;
   size_t len;
   int has_syntax = syntax_present(wp);
-  int col;
+  colnr_T col;
   char_u *buf = NULL;
   size_t buflen = 0;
   int skip = 0;
-  int capcol = -1;
+  colnr_T capcol = -1;
   bool found_one = false;
   bool wrapped = false;
 
@@ -1228,6 +1247,8 @@ size_t spell_move_to(win_T *wp, int dir, bool allwords, bool curline, hlf_T *att
     return 0;
   }
 
+  size_t ret = 0;
+
   // Start looking for bad word at the start of the line, because we can't
   // start halfway through a word, we don't know where it starts or ends.
   //
@@ -1240,6 +1261,19 @@ size_t spell_move_to(win_T *wp, int dir, bool allwords, bool curline, hlf_T *att
   linenr_T lnum = wp->w_cursor.lnum;
   clearpos(&found_pos);
 
+  char *decor_error = NULL;
+  // Ephemeral extmarks are currently stored in the global decor_state.
+  // When looking for spell errors, we need to:
+  //  - temporarily reset decor_state
+  //  - run the _on_spell_nav decor callback for each line we look at
+  //  - detect if any spell marks are present
+  //  - restore decor_state to the value saved here.
+  // TODO(lewis6991): un-globalize decor_state and allow ephemeral marks to be stored into a
+  // temporary DecorState.
+  DecorState saved_decor_start = decor_state;
+  linenr_T decor_lnum = -1;
+  decor_spell_nav_start(wp);
+
   while (!got_int) {
     char_u *line = ml_get_buf(wp->w_buffer, lnum, false);
 
@@ -1258,10 +1292,10 @@ size_t spell_move_to(win_T *wp, int dir, bool allwords, bool curline, hlf_T *att
 
     // For checking first word with a capital skip white space.
     if (capcol == 0) {
-      capcol = (int)getwhitecols((char *)line);
+      capcol = (colnr_T)getwhitecols((char *)line);
     } else if (curline && wp == curwin) {
       // For spellbadword(): check if first word needs a capital.
-      col = (int)getwhitecols((char *)line);
+      col = (colnr_T)getwhitecols((char *)line);
       if (check_need_cap(lnum, col)) {
         capcol = col;
       }
@@ -1308,33 +1342,37 @@ size_t spell_move_to(win_T *wp, int dir, bool allwords, bool curline, hlf_T *att
               || ((colnr_T)(curline
                             ? p - buf + (ptrdiff_t)len
                             : p - buf) > wp->w_cursor.col)) {
-            bool can_spell;
-            if (has_syntax) {
-              col = (int)(p - buf);
-              (void)syn_get_id(wp, lnum, (colnr_T)col,
-                               false, &can_spell, false);
-              if (!can_spell) {
-                attr = HLF_COUNT;
-              }
-            } else {
-              can_spell = true;
+            col = (colnr_T)(p - buf);
+
+            bool can_spell = (wp->w_s->b_p_spo_flags & SPO_NPBUFFER) == 0;
+
+            if (!can_spell) {
+              can_spell = decor_spell_nav_col(wp, lnum, &decor_lnum, col, &decor_error);
+            }
+
+            if (!can_spell && has_syntax) {
+              (void)syn_get_id(wp, lnum, col, false, &can_spell, false);
+            }
+
+            if (!can_spell) {
+              attr = HLF_COUNT;
             }
 
             if (can_spell) {
               found_one = true;
               found_pos = (pos_T) {
                 .lnum = lnum,
-                .col = (int)(p - buf),
+                .col = col,
                 .coladd = 0
               };
               if (dir == FORWARD) {
                 // No need to search further.
                 wp->w_cursor = found_pos;
-                xfree(buf);
                 if (attrp != NULL) {
                   *attrp = attr;
                 }
-                return len;
+                ret = len;
+                goto theend;
               } else if (curline) {
                 // Insert mode completion: put cursor after
                 // the bad word.
@@ -1358,8 +1396,8 @@ size_t spell_move_to(win_T *wp, int dir, bool allwords, bool curline, hlf_T *att
     if (dir == BACKWARD && found_pos.lnum != 0) {
       // Use the last match in the line (before the cursor).
       wp->w_cursor = found_pos;
-      xfree(buf);
-      return found_len;
+      ret = found_len;
+      goto theend;
     }
 
     if (curline) {
@@ -1429,8 +1467,12 @@ size_t spell_move_to(win_T *wp, int dir, bool allwords, bool curline, hlf_T *att
     line_breakcheck();
   }
 
+theend:
+  decor_state_free(&decor_state);
+  xfree(decor_error);
+  decor_state = saved_decor_start;
   xfree(buf);
-  return 0;
+  return ret;
 }
 
 // For spell checking: concatenate the start of the following line "line" into