feat(api): add nvim_get_hl (#22693)

Problem: no way of getting all highlight group definitions in a namespace.

Solution: add `nvim_get_hl()`, deprecate `nvim_get_hl_by_name()` and `nvim_get_hl_by_id()`.

src/nvim/api/deprecated.c

@@ -10,11 +10,14 @@
 #include "nvim/api/extmark.h"
 #include "nvim/api/private/defs.h"
 #include "nvim/api/private/helpers.h"
+#include "nvim/api/private/validate.h"
 #include "nvim/api/vimscript.h"
 #include "nvim/buffer_defs.h"
 #include "nvim/decoration.h"
 #include "nvim/extmark.h"
 #include "nvim/globals.h"
+#include "nvim/highlight.h"
+#include "nvim/highlight_group.h"
 #include "nvim/lua/executor.h"
 #include "nvim/memory.h"
 #include "nvim/pos.h"
@@ -159,6 +162,49 @@ Integer nvim_buf_set_virtual_text(Buffer buffer, Integer src_id, Integer line, A
   return src_id;
 }
 
+/// Gets a highlight definition by id. |hlID()|
+///
+/// @deprecated use |nvim_get_hl()| instead
+///
+/// @param hl_id Highlight id as returned by |hlID()|
+/// @param rgb Export RGB colors
+/// @param[out] err Error details, if any
+/// @return Highlight definition map
+/// @see nvim_get_hl_by_name
+Dictionary nvim_get_hl_by_id(Integer hl_id, Boolean rgb, Arena *arena, Error *err)
+  FUNC_API_SINCE(3)
+  FUNC_API_DEPRECATED_SINCE(9)
+{
+  Dictionary dic = ARRAY_DICT_INIT;
+  VALIDATE_INT((syn_get_final_id((int)hl_id) != 0), "highlight id", hl_id, {
+    return dic;
+  });
+  int attrcode = syn_id2attr((int)hl_id);
+  return hl_get_attr_by_id(attrcode, rgb, arena, err);
+}
+
+/// Gets a highlight definition by name.
+///
+/// @deprecated use |nvim_get_hl()| instead
+///
+/// @param name Highlight group name
+/// @param rgb Export RGB colors
+/// @param[out] err Error details, if any
+/// @return Highlight definition map
+/// @see nvim_get_hl_by_id
+Dictionary nvim_get_hl_by_name(String name, Boolean rgb, Arena *arena, Error *err)
+  FUNC_API_SINCE(3)
+  FUNC_API_DEPRECATED_SINCE(9)
+{
+  Dictionary result = ARRAY_DICT_INIT;
+  int id = syn_name2id(name.data);
+
+  VALIDATE_S((id != 0), "highlight name", name.data, {
+    return result;
+  });
+  return nvim_get_hl_by_id(id, rgb, arena, err);
+}
+
 /// Inserts a sequence of lines to a buffer at a certain index
 ///
 /// @deprecated use nvim_buf_set_lines(buffer, lnum, lnum, true, lines)

src/nvim/api/keysets.lua

@@ -145,6 +145,11 @@ return {
     "altfont";
     "nocombine";
   }};
+  { 'get_highlight', {
+    "id";
+    "name";
+    "link";
+  }};
   -- Autocmds
   { 'clear_autocmds', {
     "buffer";

src/nvim/api/ui.c

@@ -727,8 +727,8 @@ void remote_ui_hl_attr_define(UI *ui, Integer id, HlAttrs rgb_attrs, HlAttrs cte
   ADD_C(args, INTEGER_OBJ(id));
   MAXSIZE_TEMP_DICT(rgb, HLATTRS_DICT_SIZE);
   MAXSIZE_TEMP_DICT(cterm, HLATTRS_DICT_SIZE);
-  hlattrs2dict(&rgb, rgb_attrs, true);
-  hlattrs2dict(&cterm, rgb_attrs, false);
+  hlattrs2dict(&rgb, rgb_attrs, true, false);
+  hlattrs2dict(&cterm, rgb_attrs, false, false);
   ADD_C(args, DICTIONARY_OBJ(rgb));
   ADD_C(args, DICTIONARY_OBJ(cterm));
 
@@ -751,7 +751,7 @@ void remote_ui_highlight_set(UI *ui, int id)
   }
   data->hl_id = id;
   MAXSIZE_TEMP_DICT(dict, HLATTRS_DICT_SIZE);
-  hlattrs2dict(&dict, syn_attr2entry(id), ui->rgb);
+  hlattrs2dict(&dict, syn_attr2entry(id), ui->rgb, false);
   ADD_C(args, DICTIONARY_OBJ(dict));
   push_call(ui, "highlight_set", args);
 }
@@ -950,7 +950,7 @@ static Array translate_contents(UI *ui, Array contents, Arena *arena)
     int attr = (int)item.items[0].data.integer;
     if (attr) {
       Dictionary rgb_attrs = arena_dict(arena, HLATTRS_DICT_SIZE);
-      hlattrs2dict(&rgb_attrs, syn_attr2entry(attr), ui->rgb);
+      hlattrs2dict(&rgb_attrs, syn_attr2entry(attr), ui->rgb, false);
       ADD(new_item, DICTIONARY_OBJ(rgb_attrs));
     } else {
       ADD(new_item, DICTIONARY_OBJ((Dictionary)ARRAY_DICT_INIT));

src/nvim/api/vim.c

@@ -74,42 +74,6 @@
 # include "api/vim.c.generated.h"
 #endif
 
-/// Gets a highlight definition by name.
-///
-/// @param name Highlight group name
-/// @param rgb Export RGB colors
-/// @param[out] err Error details, if any
-/// @return Highlight definition map
-/// @see nvim_get_hl_by_id
-Dictionary nvim_get_hl_by_name(String name, Boolean rgb, Arena *arena, Error *err)
-  FUNC_API_SINCE(3)
-{
-  Dictionary result = ARRAY_DICT_INIT;
-  int id = syn_name2id(name.data);
-
-  VALIDATE_S((id != 0), "highlight name", name.data, {
-    return result;
-  });
-  return nvim_get_hl_by_id(id, rgb, arena, err);
-}
-
-/// Gets a highlight definition by id. |hlID()|
-/// @param hl_id Highlight id as returned by |hlID()|
-/// @param rgb Export RGB colors
-/// @param[out] err Error details, if any
-/// @return Highlight definition map
-/// @see nvim_get_hl_by_name
-Dictionary nvim_get_hl_by_id(Integer hl_id, Boolean rgb, Arena *arena, Error *err)
-  FUNC_API_SINCE(3)
-{
-  Dictionary dic = ARRAY_DICT_INIT;
-  VALIDATE_INT((syn_get_final_id((int)hl_id) != 0), "highlight id", hl_id, {
-    return dic;
-  });
-  int attrcode = syn_id2attr((int)hl_id);
-  return hl_get_attr_by_id(attrcode, rgb, arena, err);
-}
-
 /// Gets a highlight group by name
 ///
 /// similar to |hlID()|, but allocates a new ID if not present.
@@ -119,12 +83,22 @@ Integer nvim_get_hl_id_by_name(String name)
   return syn_check_group(name.data, name.size);
 }
 
-Dictionary nvim__get_hl_defs(Integer ns_id, Arena *arena, Error *err)
+/// Gets all or specific highlight groups in a namespace.
+///
+/// @param ns_id Get highlight groups for namespace ns_id |nvim_get_namespaces()|.
+///              Use 0 to get global highlight groups |:highlight|.
+/// @param opts  Options dict:
+///                 - name: (string) Get a highlight definition by name.
+///                 - id: (integer) Get a highlight definition by id.
+///                 - link: (boolean, default true) Show linked group name instead of effective definition |:hi-link|.
+///
+/// @param[out] err Error details, if any.
+/// @return Highlight groups as a map from group name to a highlight definition map as in |nvim_set_hl()|,
+///                   or only a single highlight definition map if requested by name or id.
+Dictionary nvim_get_hl(Integer ns_id, Dict(get_highlight) *opts, Arena *arena, Error *err)
+  FUNC_API_SINCE(11)
 {
-  if (ns_id == 0) {
-    return get_global_hl_defs(arena);
-  }
-  abort();
+  return ns_get_hl_defs((NS)ns_id, opts, arena, err);
 }
 
 /// Sets a highlight group.