api: add API for themes

co-author: hlpr98 <hlpr98@gmail.com> (dict2hlattrs function)

orange is sus??

NOVEMBER DAWN

erase the lie that is redraw_later()

43 files changed, 690 insertions, 203 deletions

diff --git a/src/nvim/api/buffer.c b/src/nvim/api/buffer.c
index cad4c8314f..4569ebc713 100644
--- a/src/nvim/api/buffer.c
+++ b/src/nvim/api/buffer.c
@@ -974,9 +974,9 @@ void nvim_buf_delete(Buffer buffer, Dictionary opts, Error *err)
     String k = opts.items[i].key;
     Object v = opts.items[i].value;
     if (strequal("force", k.data)) {
-      force = api_coerce_to_bool(v, "force", false, err);
+      force = api_object_to_bool(v, "force", false, err);
     } else if (strequal("unload", k.data)) {
-      unload = api_coerce_to_bool(v, "unload", false, err);
+      unload = api_object_to_bool(v, "unload", false, err);
     } else {
       api_set_error(err, kErrorTypeValidation, "unexpected key: %s", k.data);
       return;
@@ -1441,7 +1441,7 @@ Integer nvim_buf_set_extmark(Buffer buffer, Integer ns_id,
         goto error;
       }
     } else if (strequal("ephemeral", k.data)) {
-      ephemeral = api_coerce_to_bool(*v, "ephemeral", false, err);
+      ephemeral = api_object_to_bool(*v, "ephemeral", false, err);
       if (ERROR_SET(err)) {
         goto error;
       }
diff --git a/src/nvim/api/private/helpers.c b/src/nvim/api/private/helpers.c
index 981d41ae6e..a9b1676879 100644
--- a/src/nvim/api/private/helpers.c
+++ b/src/nvim/api/private/helpers.c
@@ -1625,11 +1625,8 @@ free_exit:
 /// @param what         The name of the object, used for error message
 /// @param nil_value    What to return if the type is nil.
 /// @param err          Set if there was an error in converting to a bool
-bool api_coerce_to_bool(
-    Object obj,
-    const char *what,
-    bool nil_value,
-    Error *err)
+bool api_object_to_bool(Object obj, const char *what,
+                        bool nil_value, Error *err)
 {
   if (obj.type == kObjectTypeBoolean) {
     return obj.data.boolean;
@@ -1654,3 +1651,30 @@ const char *describe_ns(NS ns_id)
   })
   return "(UNKNOWN PLUGIN)";
 }
+
+DecorationProvider *get_provider(NS ns_id, bool force)
+{
+  ssize_t i;
+  for (i = 0; i < (ssize_t)kv_size(decoration_providers); i++) {
+    DecorationProvider *item = &kv_A(decoration_providers, i);
+    if (item->ns_id == ns_id) {
+      return item;
+    } else if (item->ns_id > ns_id) {
+      break;
+    }
+  }
+
+  if (!force) {
+    return NULL;
+  }
+
+  for (ssize_t j = (ssize_t)kv_size(decoration_providers)-1; j >= i; j++) {
+    // allocates if needed:
+    (void)kv_a(decoration_providers, (size_t)j+1);
+    kv_A(decoration_providers, (size_t)j+1) = kv_A(decoration_providers, j);
+  }
+  DecorationProvider *item = &kv_a(decoration_providers, (size_t)i);
+  *item = DECORATION_PROVIDER_INIT(ns_id);
+
+  return item;
+}
diff --git a/src/nvim/api/vim.c b/src/nvim/api/vim.c
index 876b052a8e..24d82ccd0f 100644
--- a/src/nvim/api/vim.c
+++ b/src/nvim/api/vim.c
@@ -199,6 +199,69 @@ Integer nvim_get_hl_id_by_name(String name)
   return syn_check_group((const char_u *)name.data, (int)name.size);
 }
 
+Dictionary nvim__get_hl_defs(Integer ns_id, Error *err)
+{
+  if (ns_id == 0) {
+    return get_global_hl_defs();
+  }
+  abort();
+}
+
+/// Set a highlight group.
+///
+/// @param ns_id number of namespace for this highlight
+/// @param name highlight group name, like ErrorMsg
+/// @param val highlight definiton map, like |nvim_get_hl_by_name|.
+/// @param[out] err Error details, if any
+///
+/// TODO: ns_id = 0, should modify :highlight namespace
+/// TODO val should take update vs reset flag
+void nvim_set_hl(Integer ns_id, String name, Dictionary val, Error *err)
+  FUNC_API_SINCE(7)
+{
+  int hl_id = syn_check_group( (char_u *)(name.data), (int)name.size);
+  int link_id = -1;
+
+  HlAttrs attrs = dict2hlattrs(val, true, &link_id, err);
+  if (!ERROR_SET(err)) {
+    ns_hl_def((NS)ns_id, hl_id, attrs, link_id);
+  }
+}
+
+/// Set active namespace for highlights.
+///
+/// NB: this function can be called from async contexts, but the
+/// semantics are not yet well-defined. To start with
+/// |nvim_set_decoration_provider| on_win and on_line callbacks
+/// are explicitly allowed to change the namespace during a redraw cycle.
+///
+/// @param ns_id the namespace to activate
+/// @param[out] err Error details, if any
+void nvim_set_hl_ns(Integer ns_id, Error *err)
+  FUNC_API_SINCE(7)
+  FUNC_API_FAST
+{
+  if (ns_id >= 0) {
+    ns_hl_active = (NS)ns_id;
+  }
+
+  // TODO(bfredl): this is a little bit hackish.  Eventually we want a standard
+  // event path for redraws caused by "fast" events. This could tie in with
+  // better throttling of async events causing redraws, such as non-batched
+  // nvim_buf_set_extmark calls from async contexts.
+  if (!updating_screen && !ns_hl_changed) {
+    multiqueue_put(main_loop.events, on_redraw_event, 0);
+  }
+  ns_hl_changed = true;
+}
+
+static void on_redraw_event(void **argv)
+  FUNC_API_NOEXPORT
+{
+  redraw_all_later(NOT_VALID);
+}
+
+
 /// Sends input-keys to Nvim, subject to various quirks controlled by `mode`
 /// flags. This is a blocking call, unlike |nvim_input()|.
 ///
@@ -1477,7 +1540,7 @@ void nvim_unsubscribe(uint64_t channel_id, String event)
 Integer nvim_get_color_by_name(String name)
   FUNC_API_SINCE(1)
 {
-  return name_to_color((char_u *)name.data);
+  return name_to_color(name.data);
 }
 
 /// Returns a map of color names and RGB values.
@@ -2610,33 +2673,6 @@ void nvim__screenshot(String path)
   ui_call_screenshot(path);
 }
 
-static DecorationProvider *get_provider(NS ns_id, bool force)
-{
-  ssize_t i;
-  for (i = 0; i < (ssize_t)kv_size(decoration_providers); i++) {
-    DecorationProvider *item = &kv_A(decoration_providers, i);
-    if (item->ns_id == ns_id) {
-      return item;
-    } else if (item->ns_id > ns_id) {
-      break;
-    }
-  }
-
-  if (!force) {
-    return NULL;
-  }
-
-  for (ssize_t j = (ssize_t)kv_size(decoration_providers)-1; j >= i; j++) {
-    // allocates if needed:
-    (void)kv_a(decoration_providers, (size_t)j+1);
-    kv_A(decoration_providers, (size_t)j+1) = kv_A(decoration_providers, j);
-  }
-  DecorationProvider *item = &kv_a(decoration_providers, (size_t)i);
-  *item = DECORATION_PROVIDER_INIT(ns_id);
-
-  return item;
-}
-
 static void clear_provider(DecorationProvider *p)
 {
   NLUA_CLEAR_REF(p->redraw_start);
@@ -2695,7 +2731,7 @@ void nvim_set_decoration_provider(Integer ns_id, DictionaryOf(LuaRef) opts,
   clear_provider(p);
 
   // regardless of what happens, it seems good idea to redraw
-  redraw_later(NOT_VALID);  // TODO(bfredl): too soon?
+  redraw_all_later(NOT_VALID);  // TODO(bfredl): too soon?
 
   struct {
     const char *name;
@@ -2706,6 +2742,7 @@ void nvim_set_decoration_provider(Integer ns_id, DictionaryOf(LuaRef) opts,
     { "on_win", &p->redraw_win },
     { "on_line", &p->redraw_line },
     { "on_end", &p->redraw_end },
+    { "_on_hl_def", &p->hl_def },
     { NULL, NULL },
   };
 
diff --git a/src/nvim/api/window.c b/src/nvim/api/window.c
index ba43bc6cb2..f09a03f592 100644
--- a/src/nvim/api/window.c
+++ b/src/nvim/api/window.c
@@ -142,7 +142,7 @@ void nvim_win_set_cursor(Window window, ArrayOf(Integer, 2) pos, Error *err)
   // make sure cursor is in visible range even if win != curwin
   update_topline_win(win);
 
-  redraw_win_later(win, VALID);
+  redraw_later(win, VALID);
 }
 
 /// Gets the window height
@@ -471,7 +471,7 @@ void nvim_win_set_config(Window window, Dictionary config, Error *err)
     if (!win_new_float(win, fconfig, err)) {
       return;
     }
-    redraw_later(NOT_VALID);
+    redraw_later(win, NOT_VALID);
   } else {
     win_config_float(win, fconfig);
     win->w_pos_changed = true;
diff --git a/src/nvim/buffer.c b/src/nvim/buffer.c
index 8f631ae13b..9cd2fd4beb 100644
--- a/src/nvim/buffer.c
+++ b/src/nvim/buffer.c
@@ -1623,7 +1623,7 @@ void enter_buffer(buf_T *buf)
   }
   curbuf->b_last_used = time(NULL);
 
-  redraw_later(NOT_VALID);
+  redraw_later(curwin, NOT_VALID);
 }
 
 // Change to the directory of the current buffer.
diff --git a/src/nvim/change.c b/src/nvim/change.c
index be52750c44..9ee987b45d 100644
--- a/src/nvim/change.c
+++ b/src/nvim/change.c
@@ -294,7 +294,7 @@ static void changed_common(linenr_T lnum, colnr_T col, linenr_T lnume,
       // change.
       if (wp->w_p_rnu
           || (wp->w_p_cul && lnum <= wp->w_last_cursorline)) {
-        redraw_win_later(wp, SOME_VALID);
+        redraw_later(wp, SOME_VALID);
       }
     }
   }
@@ -348,7 +348,7 @@ void changed_bytes(linenr_T lnum, colnr_T col)
 
     FOR_ALL_WINDOWS_IN_TAB(wp, curtab) {
       if (wp->w_p_diff && wp != curwin) {
-        redraw_win_later(wp, VALID);
+        redraw_later(wp, VALID);
         wlnum = diff_lnum_win(lnum, wp);
         if (wlnum > 0) {
             changedOneline(wp->w_buffer, wlnum);
@@ -475,7 +475,7 @@ changed_lines(
 
     FOR_ALL_WINDOWS_IN_TAB(wp, curtab) {
       if (wp->w_p_diff && wp != curwin) {
-        redraw_win_later(wp, VALID);
+        redraw_later(wp, VALID);
         wlnum = diff_lnum_win(lnum, wp);
         if (wlnum > 0) {
           changed_lines_buf(wp->w_buffer, wlnum,
diff --git a/src/nvim/cursor.c b/src/nvim/cursor.c
index 036ae32589..d3ffab1759 100644
--- a/src/nvim/cursor.c
+++ b/src/nvim/cursor.c
@@ -482,7 +482,7 @@ bool leftcol_changed(void)
 
   if (retval)
     curwin->w_set_curswant = true;
-  redraw_later(NOT_VALID);
+  redraw_later(curwin, NOT_VALID);
   return retval;
 }
 
diff --git a/src/nvim/diff.c b/src/nvim/diff.c
index 3de5fc49bd..b9c293f6c8 100644
--- a/src/nvim/diff.c
+++ b/src/nvim/diff.c
@@ -643,7 +643,7 @@ void diff_redraw(bool dofold)
     if (!wp->w_p_diff) {
       continue;
     }
-    redraw_win_later(wp, SOME_VALID);
+    redraw_later(wp, SOME_VALID);
     if (dofold && foldmethodIsDiff(wp)) {
       foldUpdateAll(wp);
     }
@@ -1415,7 +1415,7 @@ void diff_win_options(win_T *wp, int addbuf)
   if (addbuf) {
     diff_buf_add(wp->w_buffer);
   }
-  redraw_win_later(wp, NOT_VALID);
+  redraw_later(wp, NOT_VALID);
 }
 
 /// Set options not to show diffs.  For the current window or all windows.
diff --git a/src/nvim/edit.c b/src/nvim/edit.c
index ac0e6cc9f6..3e62ed9036 100644
--- a/src/nvim/edit.c
+++ b/src/nvim/edit.c
@@ -8571,7 +8571,7 @@ static void ins_up(
     if (old_topline != curwin->w_topline
         || old_topfill != curwin->w_topfill
         )
-      redraw_later(VALID);
+      redraw_later(curwin, VALID);
     start_arrow(&tpos);
     can_cindent = true;
   } else {
@@ -8619,7 +8619,7 @@ static void ins_down(
     if (old_topline != curwin->w_topline
         || old_topfill != curwin->w_topfill
         )
-      redraw_later(VALID);
+      redraw_later(curwin, VALID);
     start_arrow(&tpos);
     can_cindent = true;
   } else {
@@ -9013,7 +9013,7 @@ static int ins_ctrl_ey(int tc)
       scrolldown_clamp();
     else
       scrollup_clamp();
-    redraw_later(VALID);
+    redraw_later(curwin, VALID);
   } else {
     c = ins_copychar(curwin->w_cursor.lnum + (c == Ctrl_Y ? -1 : 1));
     if (c != NUL) {
diff --git a/src/nvim/ex_cmds.c b/src/nvim/ex_cmds.c
index 3669cbbd2d..41137bf2db 100644
--- a/src/nvim/ex_cmds.c
+++ b/src/nvim/ex_cmds.c
@@ -3721,8 +3721,8 @@ static buf_T *do_sub(exarg_T *eap, proftime_T timeout,
               update_topline();
               validate_cursor();
               update_screen(SOME_VALID);
-              highlight_match = FALSE;
-              redraw_later(SOME_VALID);
+              highlight_match = false;
+              redraw_later(curwin, SOME_VALID);
 
               curwin->w_p_fen = save_p_fen;
               if (msg_row == Rows - 1)
@@ -5751,7 +5751,7 @@ static buf_T *show_sub(exarg_T *eap, pos_T old_cusr,
   }
   xfree(str);
 
-  redraw_later(SOME_VALID);
+  redraw_later(curwin, SOME_VALID);
   win_enter(save_curwin, false);  // Return to original window
   update_topline();
 
diff --git a/src/nvim/ex_docmd.c b/src/nvim/ex_docmd.c
index 211791c19d..59e9f96c3a 100644
--- a/src/nvim/ex_docmd.c
+++ b/src/nvim/ex_docmd.c
@@ -7379,7 +7379,7 @@ static void ex_syncbind(exarg_T *eap)
       else
         scrolldown(-y, TRUE);
       curwin->w_scbind_pos = topline;
-      redraw_later(VALID);
+      redraw_later(curwin, VALID);
       cursor_correct();
       curwin->w_redr_status = TRUE;
     }
@@ -8504,7 +8504,7 @@ static void ex_pedit(exarg_T *eap)
   if (curwin != curwin_save && win_valid(curwin_save)) {
     // Return cursor to where we were
     validate_cursor();
-    redraw_later(VALID);
+    redraw_later(curwin, VALID);
     win_enter(curwin_save, true);
   }
   g_do_tagpreview = 0;
diff --git a/src/nvim/ex_getln.c b/src/nvim/ex_getln.c
index d67e9b2d7e..53feffd2d7 100644
--- a/src/nvim/ex_getln.c
+++ b/src/nvim/ex_getln.c
@@ -6483,7 +6483,7 @@ static int open_cmdwin(void)
     ccline.redraw_state = kCmdRedrawNone;
     ui_call_cmdline_hide(ccline.level);
   }
-  redraw_later(SOME_VALID);
+  redraw_later(curwin, SOME_VALID);
 
   // Save the command line info, can be used recursively.
   save_cmdline(&save_ccline);
diff --git a/src/nvim/extmark_defs.h b/src/nvim/extmark_defs.h
index f5ca0ebbb0..382aaf6ed3 100644
--- a/src/nvim/extmark_defs.h
+++ b/src/nvim/extmark_defs.h
@@ -50,10 +50,13 @@ typedef struct {
   LuaRef redraw_win;
   LuaRef redraw_line;
   LuaRef redraw_end;
+  LuaRef hl_def;
+  int hl_valid;
 } DecorationProvider;
 
 #define DECORATION_PROVIDER_INIT(ns_id) (DecorationProvider) \
                                  { ns_id, false, LUA_NOREF, LUA_NOREF, \
-                                   LUA_NOREF, LUA_NOREF, LUA_NOREF }
+                                   LUA_NOREF, LUA_NOREF, LUA_NOREF, \
+                                   LUA_NOREF, -1 }
 
 #endif  // NVIM_EXTMARK_DEFS_H
diff --git a/src/nvim/fold.c b/src/nvim/fold.c
index 197aedabec..57001f77ed 100644
--- a/src/nvim/fold.c
+++ b/src/nvim/fold.c
@@ -862,7 +862,7 @@ void foldUpdateAfterInsert(void)
 void foldUpdateAll(win_T *win)
 {
   win->w_foldinvalid = true;
-  redraw_win_later(win, NOT_VALID);
+  redraw_later(win, NOT_VALID);
 }
 
 // foldMoveTo() {{{2
diff --git a/src/nvim/globals.h b/src/nvim/globals.h
index 2db8689a56..7f3e4a7dfc 100644
--- a/src/nvim/globals.h
+++ b/src/nvim/globals.h
@@ -92,6 +92,10 @@ EXTERN struct nvim_stats_s {
 EXTERN int Rows INIT(= DFLT_ROWS);     // nr of rows in the screen
 EXTERN int Columns INIT(= DFLT_COLS);  // nr of columns in the screen
 
+EXTERN NS ns_hl_active INIT(= 0);         // current ns that defines highlights
+EXTERN bool ns_hl_changed INIT(= false);  // highlight need update
+
+
 // We use 64-bit file functions here, if available.  E.g. ftello() returns
 // off_t instead of long, which helps if long is 32 bit and off_t is 64 bit.
 // We assume that when fseeko() is available then ftello() is too.
diff --git a/src/nvim/highlight.c b/src/nvim/highlight.c
index 262afba07a..8403615166 100644
--- a/src/nvim/highlight.c
+++ b/src/nvim/highlight.c
@@ -14,6 +14,7 @@
 #include "nvim/ui.h"
 #include "nvim/api/private/defs.h"
 #include "nvim/api/private/helpers.h"
+#include "nvim/lua/executor.h"
 
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "highlight.c.generated.h"
@@ -28,12 +29,16 @@ static Map(int, int) *combine_attr_entries;
 static Map(int, int) *blend_attr_entries;
 static Map(int, int) *blendthrough_attr_entries;
 
+/// highlight entries private to a namespace
+static Map(ColorKey, ColorItem) *ns_hl;
+
 void highlight_init(void)
 {
   attr_entry_ids = map_new(HlEntry, int)();
   combine_attr_entries = map_new(int, int)();
   blend_attr_entries = map_new(int, int)();
   blendthrough_attr_entries = map_new(int, int)();
+  ns_hl = map_new(ColorKey, ColorItem)();
 
   // index 0 is no attribute, add dummy entry:
   kv_push(attr_entries, ((HlEntry){ .attr = HLATTRS_INIT, .kind = kHlUnknown,
@@ -129,21 +134,114 @@ void ui_send_all_hls(UI *ui)
 }
 
 /// Get attribute code for a syntax group.
-int hl_get_syn_attr(int idx, HlAttrs at_en)
+int hl_get_syn_attr(int ns_id, int idx, HlAttrs at_en)
 {
   // TODO(bfredl): should we do this unconditionally
   if (at_en.cterm_fg_color != 0 || at_en.cterm_bg_color != 0
       || at_en.rgb_fg_color != -1 || at_en.rgb_bg_color != -1
       || at_en.rgb_sp_color != -1 || at_en.cterm_ae_attr != 0
-      || at_en.rgb_ae_attr != 0) {
+      || at_en.rgb_ae_attr != 0 || ns_id != 0) {
     return get_attr_entry((HlEntry){ .attr = at_en, .kind = kHlSyntax,
-                                     .id1 = idx, .id2 = 0 });
+                                     .id1 = idx, .id2 = ns_id });
   } else {
     // If all the fields are cleared, clear the attr field back to default value
     return 0;
   }
 }
 
+static ColorKey colored_key(NS ns_id, int syn_id)
+{
+  return (ColorKey){ .ns_id = (int)ns_id, .syn_id = syn_id };
+}
+
+void ns_hl_def(NS ns_id, int hl_id, HlAttrs attrs, int link_id)
+{
+  DecorationProvider *p = get_provider(ns_id, true);
+  int attr_id = link_id > 0 ? -1 : hl_get_syn_attr(ns_id, hl_id, attrs);
+  ColorItem it = { .attr_id = attr_id,
+                   .link_id = link_id,
+                   .version = p->hl_valid };
+  map_put(ColorKey, ColorItem)(ns_hl, colored_key(ns_id, hl_id), it);
+}
+
+int ns_get_hl(NS ns_id, int hl_id, bool link)
+{
+  static int recursive = 0;
+
+  if (ns_id < 0) {
+    if (ns_hl_active <= 0) {
+      return -1;
+    }
+    ns_id = ns_hl_active;
+  }
+
+  DecorationProvider *p = get_provider(ns_id, true);
+  ColorItem it = map_get(ColorKey, ColorItem)(ns_hl, colored_key(ns_id, hl_id));
+  // TODO(bfredl): map_ref true even this?
+  bool valid_cache = it.version >= p->hl_valid;
+
+  if (!valid_cache && p->hl_def != LUA_NOREF && !recursive) {
+    FIXED_TEMP_ARRAY(args, 3);
+    args.items[0] = INTEGER_OBJ((Integer)ns_id);
+    args.items[1] = STRING_OBJ(cstr_to_string((char *)syn_id2name(hl_id)));
+    args.items[2] = BOOLEAN_OBJ(link);
+    // TODO(bfredl): preload the "global" attr dict?
+
+    Error err = ERROR_INIT;
+    recursive++;
+    Object ret = nlua_call_ref(p->hl_def, "hl_def", args, true, &err);
+    recursive--;
+
+    // TODO(bfredl): or "inherit", combine with global value?
+    bool fallback = true;
+    int tmp = false;
+    HlAttrs attrs = HLATTRS_INIT;
+    if (ret.type == kObjectTypeDictionary) {
+      Dictionary dict = ret.data.dictionary;
+      fallback = false;
+      attrs = dict2hlattrs(dict, true, &it.link_id, &err);
+      for (size_t i = 0; i < dict.size; i++) {
+        char *key = dict.items[i].key.data;
+        Object val = dict.items[i].value;
+        bool truthy = api_object_to_bool(val, key, false, &err);
+
+        if (strequal(key, "fallback")) {
+          fallback = truthy;
+        } else if (strequal(key, "temp")) {
+          tmp = truthy;
+        }
+      }
+      if (it.link_id >= 0) {
+        fallback = true;
+      }
+    }
+
+    it.attr_id = fallback ? -1 : hl_get_syn_attr((int)ns_id, hl_id, attrs);
+    it.version = p->hl_valid-tmp;
+    map_put(ColorKey, ColorItem)(ns_hl, colored_key(ns_id, hl_id), it);
+  }
+
+  if (link) {
+    return it.attr_id >= 0 ? -1 : it.link_id;
+  } else {
+    return it.attr_id;
+  }
+}
+
+
+bool win_check_ns_hl(win_T *wp)
+{
+  if (ns_hl_changed) {
+    highlight_changed();
+    if (wp) {
+      update_window_hl(wp, true);
+    }
+    ns_hl_changed = false;
+    return true;
+  }
+  return false;
+}
+
 /// Get attribute code for a builtin highlight group.
 ///
 /// The final syntax group could be modified by hi-link or 'winhighlight'.
@@ -204,6 +302,17 @@ void update_window_hl(win_T *wp, bool invalid)
     wp->w_hl_attr_normal = float_win ? HL_ATTR(HLF_NFLOAT) : 0;
   }
 
+  // NOOOO! You cannot just pretend that "Normal" is just like any other
+  // syntax group! It needs at least 10 layers of special casing! Noooooo!
+  //
+  // haha, theme engine go brrr
+  int normality = syn_check_group((const char_u *)S_LEN("Normal"));
+  int ns_attr = ns_get_hl(-1, normality, false);
+  if (ns_attr > 0) {
+    // TODO(bfredl): hantera NormalNC and so on
+    wp->w_hl_attr_normal = ns_attr;
+  }
+
   // if blend= attribute is not set, 'winblend' value overrides it.
   if (wp->w_floating && wp->w_p_winbl > 0) {
     HlEntry entry = kv_A(attr_entries, wp->w_hl_attr_normal);
@@ -275,6 +384,7 @@ void clear_hl_tables(bool reinit)
     map_free(int, int)(combine_attr_entries);
     map_free(int, int)(blend_attr_entries);
     map_free(int, int)(blendthrough_attr_entries);
+    map_free(ColorKey, ColorItem)(ns_hl);
   }
 }
 
@@ -663,6 +773,103 @@ Dictionary hlattrs2dict(HlAttrs ae, bool use_rgb)
   return hl;
 }
 
+HlAttrs dict2hlattrs(Dictionary dict, bool use_rgb, int *link_id, Error *err)
+{
+  HlAttrs hlattrs = HLATTRS_INIT;
+
+  int32_t fg = -1, bg = -1, sp = -1;
+  int16_t mask = 0;
+  for (size_t i = 0; i < dict.size; i++) {
+    char *key = dict.items[i].key.data;
+    Object val = dict.items[i].value;
+
+    struct {
+      const char *name;
+      int16_t flag;
+    } flags[] = {
+      { "bold", HL_BOLD },
+      { "standout", HL_STANDOUT },
+      { "underline", HL_UNDERLINE },
+      { "undercurl", HL_UNDERCURL },
+      { "italic", HL_ITALIC },
+      { "reverse", HL_INVERSE },
+      { NULL, 0 },
+    };
+
+    int j;
+    for (j = 0; flags[j].name; j++) {
+      if (strequal(flags[j].name, key)) {
+        if (api_object_to_bool(val, key, false, err)) {
+          mask = mask | flags[j].flag;
+        }
+        break;
+      }
+    }
+
+    struct {
+      const char *name;
+      const char *shortname;
+      int *dest;
+    } colors[] = {
+      { "foreground", "fg", &fg },
+      { "background", "bg", &bg },
+      { "special", "sp", &sp },
+      { NULL, NULL, NULL },
+    };
+
+    int k;
+    for (k = 0; (!flags[j].name) && colors[k].name; k++) {
+      if (strequal(colors[k].name, key) || strequal(colors[k].shortname, key)) {
+        if (val.type == kObjectTypeInteger) {
+          *colors[k].dest = (int)val.data.integer;
+        } else if (val.type == kObjectTypeString) {
+          String str = val.data.string;
+          // TODO(bfredl): be more fancy with "bg", "fg" etc
+          if (str.size) {
+            *colors[k].dest = name_to_color(str.data);
+          }
+        } else {
+          api_set_error(err, kErrorTypeValidation,
+                        "'%s' must be string or integer", key);
+        }
+        break;
+      }
+    }
+
+
+    if (flags[j].name || colors[k].name) {
+      // handled above
+    } else if (link_id && strequal(key, "link")) {
+      if (val.type == kObjectTypeString) {
+        String str = val.data.string;
+        *link_id = syn_check_group((const char_u *)str.data, (int)str.size);
+      } else if (val.type == kObjectTypeInteger) {
+        // TODO(bfredl): validate range?
+        *link_id = (int)val.data.integer;
+      } else {
+        api_set_error(err, kErrorTypeValidation,
+                      "'link' must be string or integer");
+      }
+    }
+
+    if (ERROR_SET(err)) {
+      return hlattrs;  // error set, caller should not use retval
+    }
+  }
+
+  if (use_rgb) {
+    hlattrs.rgb_ae_attr = mask;
+    hlattrs.rgb_bg_color = bg;
+    hlattrs.rgb_fg_color = fg;
+    hlattrs.rgb_sp_color = sp;
+  } else {
+    hlattrs.cterm_ae_attr = mask;
+    hlattrs.cterm_bg_color = bg == -1 ? cterm_normal_bg_color : bg + 1;
+    hlattrs.cterm_fg_color = fg == -1 ? cterm_normal_fg_color : fg + 1;
+  }
+
+  return hlattrs;
+}
 Array hl_inspect(int attr)
 {
   Array ret = ARRAY_DICT_INIT;
diff --git a/src/nvim/highlight_defs.h b/src/nvim/highlight_defs.h
index 36f3181674..6a5c593ab1 100644
--- a/src/nvim/highlight_defs.h
+++ b/src/nvim/highlight_defs.h
@@ -4,6 +4,7 @@
 #include <inttypes.h>
 
 #include "nvim/macros.h"
+#include "nvim/types.h"
 
 typedef int32_t RgbValue;
 
@@ -180,6 +181,20 @@ typedef struct {
   HlKind kind;
   int id1;
   int id2;
+  int winid;
 } HlEntry;
 
+typedef struct {
+  int ns_id;
+  int syn_id;
+} ColorKey;
+
+typedef struct {
+  int attr_id;
+  int link_id;
+  int version;
+} ColorItem;
+#define COLOR_ITEM_INITIALIZER { .attr_id = -1, .link_id = -1, .version = -1 }
+
+
 #endif  // NVIM_HIGHLIGHT_DEFS_H
diff --git a/src/nvim/lua/executor.c b/src/nvim/lua/executor.c
index 5c665920b5..887e8228aa 100644
--- a/src/nvim/lua/executor.c
+++ b/src/nvim/lua/executor.c
@@ -891,6 +891,17 @@ LuaRef nlua_newref(lua_State *lstate, LuaRef original_ref)
   return new_ref;
 }
 
+LuaRef api_new_luaref(LuaRef original_ref)
+{
+  if (original_ref == LUA_NOREF) {
+    return LUA_NOREF;
+  }
+
+  lua_State *const lstate = nlua_enter();
+  return nlua_newref(lstate, original_ref);
+}
+
+
 /// Evaluate lua string
 ///
 /// Used for luaeval().
diff --git a/src/nvim/main.c b/src/nvim/main.c
index a22df9cc69..27bf5c45c6 100644
--- a/src/nvim/main.c
+++ b/src/nvim/main.c
@@ -446,7 +446,7 @@ int main(int argc, char **argv)
   if (exmode_active || use_remote_ui || use_builtin_ui) {
     // Don't clear the screen when starting in Ex mode, or when a UI might have
     // displayed messages.
-    redraw_later(VALID);
+    redraw_later(curwin, VALID);
   } else {
     screenclear();  // clear screen
     TIME_MSG("clearing screen");
diff --git a/src/nvim/map.c b/src/nvim/map.c
index ca8ea76333..7d97b7f13d 100644
--- a/src/nvim/map.c
+++ b/src/nvim/map.c
@@ -12,6 +12,9 @@
 #include <stdbool.h>
 #include <string.h>
 
+#include <lua.h>
+#include <lauxlib.h>
+
 #include "nvim/map.h"
 #include "nvim/map_defs.h"
 #include "nvim/vim.h"
@@ -173,6 +176,20 @@ static inline bool HlEntry_eq(HlEntry ae1, HlEntry ae2)
   return memcmp(&ae1, &ae2, sizeof(ae1)) == 0;
 }
 
+static inline khint_t ColorKey_hash(ColorKey ae)
+{
+  const uint8_t *data = (const uint8_t *)&ae;
+  khint_t h = 0;
+  for (size_t i = 0; i < sizeof(ae); i++) {
+    h = (h << 5) - h + data[i];
+  }
+  return h;
+}
+
+static inline bool ColorKey_eq(ColorKey ae1, ColorKey ae2)
+{
+  return memcmp(&ae1, &ae2, sizeof(ae1)) == 0;
+}
 
 
 MAP_IMPL(int, int, DEFAULT_INITIALIZER)
@@ -191,6 +208,7 @@ MAP_IMPL(String, MsgpackRpcRequestHandler, MSGPACK_HANDLER_INITIALIZER)
 MAP_IMPL(HlEntry, int, DEFAULT_INITIALIZER)
 MAP_IMPL(String, handle_T, 0)
 
+MAP_IMPL(ColorKey, ColorItem, COLOR_ITEM_INITIALIZER)
 
 /// Deletes a key:value pair from a string:pointer map, and frees the
 /// storage of both key and value.
diff --git a/src/nvim/map.h b/src/nvim/map.h
index 63a18f4129..7bd3d31330 100644
--- a/src/nvim/map.h
+++ b/src/nvim/map.h
@@ -55,6 +55,8 @@ MAP_DECLS(String, MsgpackRpcRequestHandler)
 MAP_DECLS(HlEntry, int)
 MAP_DECLS(String, handle_T)
 
+MAP_DECLS(ColorKey, ColorItem)
+
 #define map_new(T, U) map_##T##_##U##_new
 #define map_free(T, U) map_##T##_##U##_free
 #define map_get(T, U) map_##T##_##U##_get
diff --git a/src/nvim/menu.c b/src/nvim/menu.c
index b060464383..4ba2e36656 100644
--- a/src/nvim/menu.c
+++ b/src/nvim/menu.c
@@ -193,7 +193,7 @@ ex_menu(exarg_T *eap)
   vimmenu_T **root_menu_ptr = get_root_menu(menu_path);
   if (root_menu_ptr == &curwin->w_winbar) {
     // Assume the window toolbar menu will change.
-    redraw_later(NOT_VALID);
+    redraw_later(curwin, NOT_VALID);
   }
 
   if (enable != kNone) {
diff --git a/src/nvim/message.c b/src/nvim/message.c
index 6cd5616acf..06ba607323 100644
--- a/src/nvim/message.c
+++ b/src/nvim/message.c
@@ -1216,7 +1216,7 @@ void wait_return(int redraw)
     ui_refresh();
   } else if (!skip_redraw) {
     if (redraw == true || (msg_scrolled != 0 && redraw != -1)) {
-      redraw_later(VALID);
+      redraw_later(curwin, VALID);
     }
     if (ui_has(kUIMessages)) {
       msg_ext_clear(true);
@@ -2222,7 +2222,7 @@ void msg_scroll_up(bool may_throttle)
 ///
 /// Probably message scrollback storage should reimplented as a file_buffer, and
 /// message scrolling in TUI be reimplemented as a modal floating window. Then
-/// we get throttling "for free" using standard redraw_win_later code paths.
+/// we get throttling "for free" using standard redraw_later code paths.
 void msg_scroll_flush(void)
 {
   if (msg_grid.throttled) {
diff --git a/src/nvim/mouse.c b/src/nvim/mouse.c
index fcd9ee4f75..d8ff83f479 100644
--- a/src/nvim/mouse.c
+++ b/src/nvim/mouse.c
@@ -286,7 +286,7 @@ retnomove:
       check_topfill(curwin, false);
       curwin->w_valid &=
         ~(VALID_WROW|VALID_CROW|VALID_BOTLINE|VALID_BOTLINE_AP);
-      redraw_later(VALID);
+      redraw_later(curwin, VALID);
       row = 0;
     } else if (row >= curwin->w_height_inner)   {
       count = 0;
@@ -316,7 +316,7 @@ retnomove:
         }
       }
       check_topfill(curwin, false);
-      redraw_later(VALID);
+      redraw_later(curwin, VALID);
       curwin->w_valid &=
         ~(VALID_WROW|VALID_CROW|VALID_BOTLINE|VALID_BOTLINE_AP);
       row = curwin->w_height_inner - 1;
diff --git a/src/nvim/move.c b/src/nvim/move.c
index e2a304efa5..98a7792a09 100644
--- a/src/nvim/move.c
+++ b/src/nvim/move.c
@@ -107,7 +107,7 @@ void redraw_for_cursorline(win_T *wp)
       && !pum_visible()) {
     if (wp->w_p_rnu) {
       // win_line() will redraw the number column only.
-      redraw_win_later(wp, VALID);
+      redraw_later(wp, VALID);
     }
     if (win_cursorline_standout(wp)) {
       if (wp->w_redr_type <= VALID && wp->w_last_cursorline != 0) {
@@ -117,7 +117,7 @@ void redraw_for_cursorline(win_T *wp)
         redrawWinline(wp, wp->w_last_cursorline);
         redrawWinline(wp, wp->w_cursor.lnum);
       } else {
-        redraw_win_later(wp, SOME_VALID);
+        redraw_later(wp, SOME_VALID);
       }
     }
   }
@@ -172,7 +172,7 @@ void update_topline(void)
   // If the buffer is empty, always set topline to 1.
   if (BUFEMPTY()) {             // special case - file is empty
     if (curwin->w_topline != 1) {
-      redraw_later(NOT_VALID);
+      redraw_later(curwin, NOT_VALID);
     }
     curwin->w_topline = 1;
     curwin->w_botline = 2;
@@ -326,12 +326,14 @@ void update_topline(void)
     dollar_vcol = -1;
     if (curwin->w_skipcol != 0) {
       curwin->w_skipcol = 0;
-      redraw_later(NOT_VALID);
-    } else
-      redraw_later(VALID);
-    /* May need to set w_skipcol when cursor in w_topline. */
-    if (curwin->w_cursor.lnum == curwin->w_topline)
+      redraw_later(curwin, NOT_VALID);
+    } else {
+      redraw_later(curwin, VALID);
+    }
+    // May need to set w_skipcol when cursor in w_topline.
+    if (curwin->w_cursor.lnum == curwin->w_topline) {
       validate_cursor();
+    }
   }
 
   *so_ptr = save_so;
@@ -439,7 +441,7 @@ void changed_window_setting_win(win_T *wp)
   wp->w_lines_valid = 0;
   changed_line_abv_curs_win(wp);
   wp->w_valid &= ~(VALID_BOTLINE|VALID_BOTLINE_AP|VALID_TOPLINE);
-  redraw_win_later(wp, NOT_VALID);
+  redraw_later(wp, NOT_VALID);
 }
 
 /*
@@ -455,8 +457,8 @@ void set_topline(win_T *wp, linenr_T lnum)
   wp->w_topline_was_set = true;
   wp->w_topfill = 0;
   wp->w_valid &= ~(VALID_WROW|VALID_CROW|VALID_BOTLINE|VALID_TOPLINE);
-  /* Don't set VALID_TOPLINE here, 'scrolloff' needs to be checked. */
-  redraw_later(VALID);
+  // Don't set VALID_TOPLINE here, 'scrolloff' needs to be checked.
+  redraw_later(wp, VALID);
 }
 
 /*
@@ -634,7 +636,7 @@ void validate_virtcol_win(win_T *wp)
     if (wp->w_p_cuc
         && !pum_visible()
         )
-      redraw_win_later(wp, SOME_VALID);
+      redraw_later(wp, SOME_VALID);
   }
 }
 
@@ -830,7 +832,7 @@ void curs_columns(
         curwin->w_leftcol = new_leftcol;
         win_check_anchored_floats(curwin);
         // screen has to be redrawn with new curwin->w_leftcol
-        redraw_later(NOT_VALID);
+        redraw_later(curwin, NOT_VALID);
       }
     }
     curwin->w_wcol -= curwin->w_leftcol;
@@ -934,13 +936,14 @@ void curs_columns(
   } else {
     curwin->w_skipcol = 0;
   }
-  if (prev_skipcol != curwin->w_skipcol)
-    redraw_later(NOT_VALID);
+  if (prev_skipcol != curwin->w_skipcol) {
+    redraw_later(curwin, NOT_VALID);
+  }
 
   /* Redraw when w_virtcol changes and 'cursorcolumn' is set */
   if (curwin->w_p_cuc && (curwin->w_valid & VALID_VIRTCOL) == 0
       && !pum_visible()) {
-    redraw_later(SOME_VALID);
+    redraw_later(curwin, SOME_VALID);
   }
 
   // now w_leftcol is valid, avoid check_cursor_moved() thinking otherwise
@@ -2013,7 +2016,7 @@ int onepage(Direction dir, long count)
     }
   }
 
-  redraw_later(VALID);
+  redraw_later(curwin, VALID);
   return retval;
 }
 
@@ -2199,7 +2202,7 @@ void halfpage(bool flag, linenr_T Prenum)
   check_topfill(curwin, !flag);
   cursor_correct();
   beginline(BL_SOL | BL_FIX);
-  redraw_later(VALID);
+  redraw_later(curwin, VALID);
 }
 
 void do_check_cursorbind(void)
@@ -2247,7 +2250,7 @@ void do_check_cursorbind(void)
       }
       // Correct cursor for multi-byte character.
       mb_adjust_cursor();
-      redraw_later(VALID);
+      redraw_later(curwin, VALID);
 
       // Only scroll when 'scrollbind' hasn't done this.
       if (!curwin->w_p_scb) {
diff --git a/src/nvim/normal.c b/src/nvim/normal.c
index 1cc400166c..a2c7dfda55 100644
--- a/src/nvim/normal.c
+++ b/src/nvim/normal.c
@@ -3601,7 +3601,7 @@ void check_scrollbind(linenr_T topline_diff, long leftcol_diff)
           scrolldown(-y, false);
       }
 
-      redraw_later(VALID);
+      redraw_later(curwin, VALID);
       cursor_correct();
       curwin->w_redr_status = true;
     }
@@ -4143,7 +4143,7 @@ void scroll_redraw(int up, long count)
   if (curwin->w_cursor.lnum != prev_lnum)
     coladvance(curwin->w_curswant);
   curwin->w_viewport_invalid = true;
-  redraw_later(VALID);
+  redraw_later(curwin, VALID);
 }
 
 /*
@@ -4241,7 +4241,7 @@ dozet:
     FALLTHROUGH;
 
   case 't':   scroll_cursor_top(0, true);
-    redraw_later(VALID);
+    redraw_later(curwin, VALID);
     set_fraction(curwin);
     break;
 
@@ -4250,7 +4250,7 @@ dozet:
   FALLTHROUGH;
 
   case 'z':   scroll_cursor_halfway(true);
-    redraw_later(VALID);
+    redraw_later(curwin, VALID);
     set_fraction(curwin);
     break;
 
@@ -4271,7 +4271,7 @@ dozet:
     FALLTHROUGH;
 
   case 'b':   scroll_cursor_bot(0, true);
-    redraw_later(VALID);
+    redraw_later(curwin, VALID);
     set_fraction(curwin);
     break;
 
@@ -4318,7 +4318,7 @@ dozet:
         col = 0;
       if (curwin->w_leftcol != col) {
         curwin->w_leftcol = col;
-        redraw_later(NOT_VALID);
+        redraw_later(curwin, NOT_VALID);
       }
   }
     break;
@@ -4337,7 +4337,7 @@ dozet:
       }
       if (curwin->w_leftcol != col) {
         curwin->w_leftcol = col;
-        redraw_later(NOT_VALID);
+        redraw_later(curwin, NOT_VALID);
       }
   }
     break;
@@ -4690,7 +4690,7 @@ static void nv_clear(cmdarg_T *cap)
     FOR_ALL_WINDOWS_IN_TAB(wp, curtab) {
       wp->w_s->b_syn_slow = false;
     }
-    redraw_later(CLEAR);
+    redraw_later(curwin, CLEAR);
   }
 }
 
diff --git a/src/nvim/ops.c b/src/nvim/ops.c
index 939cde0ba1..9e7d81fc82 100644
--- a/src/nvim/ops.c
+++ b/src/nvim/ops.c
@@ -2652,7 +2652,7 @@ static void op_yank_reg(oparg_T *oap, bool message, yankreg_T *reg, bool append)
     xfree(reg->y_array);
   }
   if (curwin->w_p_rnu) {
-    redraw_later(SOME_VALID);  // cursor moved to start
+    redraw_later(curwin, SOME_VALID);  // cursor moved to start
   }
   if (message) {  // Display message about yank?
     if (yank_type == kMTCharWise && yanklines == 1) {
diff --git a/src/nvim/option.c b/src/nvim/option.c
index ca902d5669..4f40749f7d 100644
--- a/src/nvim/option.c
+++ b/src/nvim/option.c
@@ -3121,7 +3121,7 @@ ambw_end:
     } else {
       if (curwin->w_status_height) {
         curwin->w_redr_status = true;
-        redraw_later(VALID);
+        redraw_later(curwin, VALID);
       }
       curbuf->b_help = (curbuf->b_p_bt[0] == 'h');
       redraw_titles();
@@ -4702,7 +4702,7 @@ static void check_redraw(uint32_t flags)
     redraw_curbuf_later(NOT_VALID);
   }
   if (flags & P_RWINONLY) {
-    redraw_later(NOT_VALID);
+    redraw_later(curwin, NOT_VALID);
   }
   if (doclear) {
     redraw_all_later(CLEAR);
@@ -5716,12 +5716,12 @@ void unset_global_local_option(char *name, void *from)
     case PV_LCS:
       clear_string_option(&((win_T *)from)->w_p_lcs);
       set_chars_option((win_T *)from, &((win_T *)from)->w_p_lcs, true);
-      redraw_win_later((win_T *)from, NOT_VALID);
+      redraw_later((win_T *)from, NOT_VALID);
       break;
     case PV_FCS:
       clear_string_option(&((win_T *)from)->w_p_fcs);
       set_chars_option((win_T *)from, &((win_T *)from)->w_p_fcs, true);
-      redraw_win_later((win_T *)from, NOT_VALID);
+      redraw_later((win_T *)from, NOT_VALID);
       break;
   }
 }
diff --git a/src/nvim/popupmnu.c b/src/nvim/popupmnu.c
index d2d20852aa..ac0c1f6eb1 100644
--- a/src/nvim/popupmnu.c
+++ b/src/nvim/popupmnu.c
@@ -786,7 +786,7 @@ static int pum_set_selected(int n, int repeat)
 
             // Return cursor to where we were
             validate_cursor();
-            redraw_later(SOME_VALID);
+            redraw_later(curwin, SOME_VALID);
 
             // When the preview window was resized we need to
             // update the view on the buffer.  Only go back to
diff --git a/src/nvim/quickfix.c b/src/nvim/quickfix.c
index 1cd7879dc0..6ca97c3072 100644
--- a/src/nvim/quickfix.c
+++ b/src/nvim/quickfix.c
@@ -3707,7 +3707,7 @@ static void qf_win_goto(win_T *win, linenr_T lnum)
   curwin->w_cursor.coladd = 0;
   curwin->w_curswant = 0;
   update_topline();              // scroll to show the line
-  redraw_later(VALID);
+  redraw_later(curwin, VALID);
   curwin->w_redr_status = true;  // update ruler
   curwin = old_curwin;
   curbuf = curwin->w_buffer;
diff --git a/src/nvim/screen.c b/src/nvim/screen.c
index df0c5ce791..cb75cba71a 100644
--- a/src/nvim/screen.c
+++ b/src/nvim/screen.c
@@ -25,7 +25,7 @@
 //
 // Commands that scroll a window change w_topline and must call
 // check_cursor() to move the cursor into the visible part of the window, and
-// call redraw_later(VALID) to have the window displayed by update_screen()
+// call redraw_later(wp, VALID) to have the window displayed by update_screen()
 // later.
 //
 // Commands that change text in the buffer must call changed_bytes() or
@@ -37,7 +37,7 @@
 //
 // Commands that change how a window is displayed (e.g., setting 'list') or
 // invalidate the contents of a window in another way (e.g., change fold
-// settings), must call redraw_later(NOT_VALID) to have the whole window
+// settings), must call redraw_later(wp, NOT_VALID) to have the whole window
 // redisplayed by update_screen() later.
 //
 // Commands that change how a buffer is displayed (e.g., setting 'tabstop')
@@ -45,11 +45,11 @@
 // buffer redisplayed by update_screen() later.
 //
 // Commands that change highlighting and possibly cause a scroll too must call
-// redraw_later(SOME_VALID) to update the whole window but still use scrolling
-// to avoid redrawing everything.  But the length of displayed lines must not
-// change, use NOT_VALID then.
+// redraw_later(wp, SOME_VALID) to update the whole window but still use
+// scrolling to avoid redrawing everything.  But the length of displayed lines
+// must not change, use NOT_VALID then.
 //
-// Commands that move the window position must call redraw_later(NOT_VALID).
+// Commands that move the window position must call redraw_later(wp, NOT_VALID).
 // TODO(neovim): should minimize redrawing by scrolling when possible.
 //
 // Commands that change everything (e.g., resizing the screen) must call
@@ -176,7 +176,7 @@ static bool provider_invoke(NS ns_id, const char *name, LuaRef ref,
   textlock--;
 
   if (!ERROR_SET(&err)
-      && api_coerce_to_bool(ret, "provider %s retval", default_true, &err)) {
+      && api_object_to_bool(ret, "provider %s retval", default_true, &err)) {
     return true;
   }
 
@@ -195,17 +195,11 @@ static bool provider_invoke(NS ns_id, const char *name, LuaRef ref,
   return false;
 }
 
-/*
- * Redraw the current window later, with update_screen(type).
- * Set must_redraw only if not already set to a higher value.
- * e.g. if must_redraw is CLEAR, type NOT_VALID will do nothing.
- */
-void redraw_later(int type)
-{
-  redraw_win_later(curwin, type);
-}
-
-void redraw_win_later(win_T *wp, int type)
+/// Redraw a window later, with update_screen(type).
+///
+/// Set must_redraw only if not already set to a higher value.
+/// e.g. if must_redraw is CLEAR, type NOT_VALID will do nothing.
+void redraw_later(win_T *wp, int type)
   FUNC_ATTR_NONNULL_ALL
 {
   if (!exiting && wp->w_redr_type < type) {
@@ -223,7 +217,7 @@ void redraw_win_later(win_T *wp, int type)
 void redraw_all_later(int type)
 {
   FOR_ALL_WINDOWS_IN_TAB(wp, curtab) {
-    redraw_win_later(wp, type);
+    redraw_later(wp, type);
   }
   // This may be needed when switching tabs.
   if (must_redraw < type) {
@@ -234,7 +228,7 @@ void redraw_all_later(int type)
 void screen_invalidate_highlights(void)
 {
   FOR_ALL_WINDOWS_IN_TAB(wp, curtab) {
-    redraw_win_later(wp, NOT_VALID);
+    redraw_later(wp, NOT_VALID);
     wp->w_grid.valid = false;
   }
 }
@@ -251,7 +245,7 @@ void redraw_buf_later(buf_T *buf, int type)
 {
   FOR_ALL_WINDOWS_IN_TAB(wp, curtab) {
     if (wp->w_buffer == buf) {
-      redraw_win_later(wp, type);
+      redraw_later(wp, type);
     }
   }
 }
@@ -277,7 +271,7 @@ void redraw_buf_range_later(buf_T *buf,  linenr_T firstline, linenr_T lastline)
       if (wp->w_redraw_bot == 0 || wp->w_redraw_bot < lastline) {
           wp->w_redraw_bot = lastline;
       }
-      redraw_win_later(wp, VALID);
+      redraw_later(wp, VALID);
     }
   }
 }
@@ -305,7 +299,7 @@ redrawWinline(
     if (wp->w_redraw_bot == 0 || wp->w_redraw_bot < lnum) {
         wp->w_redraw_bot = lnum;
     }
-    redraw_win_later(wp, VALID);
+    redraw_later(wp, VALID);
   }
 }
 
@@ -359,7 +353,6 @@ int update_screen(int type)
   /* Postpone the redrawing when it's not needed and when being called
    * recursively. */
   if (!redrawing() || updating_screen) {
-    redraw_later(type);                 /* remember type for next time */
     must_redraw = type;
     if (type > INVERTED_ALL) {
       curwin->w_lines_valid = 0;  // don't use w_lines[].wl_size now
@@ -501,6 +494,12 @@ int update_screen(int type)
     }
   }
 
+  // "start" callback could have changed highlights for global elements
+  if (win_check_ns_hl(NULL)) {
+    redraw_cmdline = true;
+    redraw_tabline = true;
+  }
+
   if (clear_cmdline)            /* going to clear cmdline (done below) */
     check_for_delay(FALSE);
 
@@ -1331,6 +1330,8 @@ static void win_update(win_T *wp, Providers *providers)
     }
   }
 
+  win_check_ns_hl(wp);
+
 
   for (;; ) {
     /* stop updating when reached the end of the window (check for _past_
@@ -2185,6 +2186,8 @@ static int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow,
           // return 'false' or error: skip rest of this window
           kv_A(*providers, k) = NULL;
         }
+
+        win_check_ns_hl(wp);
       }
     }
 
@@ -4649,8 +4652,8 @@ void status_redraw_all(void)
 
   FOR_ALL_WINDOWS_IN_TAB(wp, curtab) {
     if (wp->w_status_height) {
-      wp->w_redr_status = TRUE;
-      redraw_later(VALID);
+      wp->w_redr_status = true;
+      redraw_later(wp, VALID);
     }
   }
 }
@@ -4667,7 +4670,7 @@ void status_redraw_buf(buf_T *buf)
   FOR_ALL_WINDOWS_IN_TAB(wp, curtab) {
     if (wp->w_status_height != 0 && wp->w_buffer == buf) {
       wp->w_redr_status = true;
-      redraw_later(VALID);
+      redraw_later(wp, VALID);
     }
   }
 }
diff --git a/src/nvim/search.c b/src/nvim/search.c
index 9458e6333f..b25333c9fa 100644
--- a/src/nvim/search.c
+++ b/src/nvim/search.c
@@ -4923,7 +4923,7 @@ search_line:
             && curwin != curwin_save && win_valid(curwin_save)) {
           /* Return cursor to where we were */
           validate_cursor();
-          redraw_later(VALID);
+          redraw_later(curwin, VALID);
           win_enter(curwin_save, true);
         }
         break;
diff --git a/src/nvim/spell.c b/src/nvim/spell.c
index 1984a357c3..636c71657d 100644
--- a/src/nvim/spell.c
+++ b/src/nvim/spell.c
@@ -2258,7 +2258,7 @@ char_u *did_set_spelllang(win_T *wp)
 theend:
   xfree(spl_copy);
   recursive = false;
-  redraw_win_later(wp, NOT_VALID);
+  redraw_later(wp, NOT_VALID);
   return ret_msg;
 }
 
@@ -6877,7 +6877,7 @@ void ex_spelldump(exarg_T *eap)
   if (curbuf->b_ml.ml_line_count > 1) {
     ml_delete(curbuf->b_ml.ml_line_count, false);
   }
-  redraw_later(NOT_VALID);
+  redraw_later(curwin, NOT_VALID);
 }
 
 // Go through all possible words and:
diff --git a/src/nvim/syntax.c b/src/nvim/syntax.c
index 9a9cc45c6b..62fabc74e5 100644
--- a/src/nvim/syntax.c
+++ b/src/nvim/syntax.c
@@ -73,9 +73,9 @@ struct hl_group {
   RgbValue sg_rgb_fg;           ///< RGB foreground color
   RgbValue sg_rgb_bg;           ///< RGB background color
   RgbValue sg_rgb_sp;           ///< RGB special color
-  uint8_t *sg_rgb_fg_name;      ///< RGB foreground color name
-  uint8_t *sg_rgb_bg_name;      ///< RGB background color name
-  uint8_t *sg_rgb_sp_name;      ///< RGB special color name
+  char *sg_rgb_fg_name;         ///< RGB foreground color name
+  char *sg_rgb_bg_name;         ///< RGB background color name
+  char *sg_rgb_sp_name;         ///< RGB special color name
 
   int sg_blend;                 ///< blend level (0-100 inclusive), -1 if unset
 };
@@ -3147,7 +3147,7 @@ static void syn_cmd_spell(exarg_T *eap, int syncing)
   }
 
   // assume spell checking changed, force a redraw
-  redraw_win_later(curwin, NOT_VALID);
+  redraw_later(curwin, NOT_VALID);
 }
 
 /// Handle ":syntax iskeyword" command.
@@ -3187,7 +3187,7 @@ static void syn_cmd_iskeyword(exarg_T *eap, int syncing)
       curbuf->b_p_isk = save_isk;
     }
   }
-  redraw_win_later(curwin, NOT_VALID);
+  redraw_later(curwin, NOT_VALID);
 }
 
 /*
@@ -6899,7 +6899,7 @@ void do_highlight(const char *line, const bool forceit, const bool init)
           }
         }
       } else if (strcmp(key, "GUIFG") == 0)   {
-        char_u **const namep = &HL_TABLE()[idx].sg_rgb_fg_name;
+        char **namep = &HL_TABLE()[idx].sg_rgb_fg_name;
 
         if (!init || !(HL_TABLE()[idx].sg_set & SG_GUI)) {
           if (!init) {
@@ -6909,8 +6909,8 @@ void do_highlight(const char *line, const bool forceit, const bool init)
           if (*namep == NULL || STRCMP(*namep, arg) != 0) {
             xfree(*namep);
             if (strcmp(arg, "NONE") != 0) {
-              *namep = (char_u *)xstrdup(arg);
-              HL_TABLE()[idx].sg_rgb_fg = name_to_color((char_u *)arg);
+              *namep = xstrdup(arg);
+              HL_TABLE()[idx].sg_rgb_fg = name_to_color(arg);
             } else {
               *namep = NULL;
               HL_TABLE()[idx].sg_rgb_fg = -1;
@@ -6923,7 +6923,7 @@ void do_highlight(const char *line, const bool forceit, const bool init)
           normal_fg = HL_TABLE()[idx].sg_rgb_fg;
         }
       } else if (STRCMP(key, "GUIBG") == 0)   {
-        char_u **const namep = &HL_TABLE()[idx].sg_rgb_bg_name;
+        char **const namep = &HL_TABLE()[idx].sg_rgb_bg_name;
 
         if (!init || !(HL_TABLE()[idx].sg_set & SG_GUI)) {
           if (!init) {
@@ -6933,8 +6933,8 @@ void do_highlight(const char *line, const bool forceit, const bool init)
           if (*namep == NULL || STRCMP(*namep, arg) != 0) {
             xfree(*namep);
             if (STRCMP(arg, "NONE") != 0) {
-              *namep = (char_u *)xstrdup(arg);
-              HL_TABLE()[idx].sg_rgb_bg = name_to_color((char_u *)arg);
+              *namep = xstrdup(arg);
+              HL_TABLE()[idx].sg_rgb_bg = name_to_color(arg);
             } else {
               *namep = NULL;
               HL_TABLE()[idx].sg_rgb_bg = -1;
@@ -6947,7 +6947,7 @@ void do_highlight(const char *line, const bool forceit, const bool init)
           normal_bg = HL_TABLE()[idx].sg_rgb_bg;
         }
       } else if (strcmp(key, "GUISP") == 0)   {
-        char_u **const namep = &HL_TABLE()[idx].sg_rgb_sp_name;
+        char **const namep = &HL_TABLE()[idx].sg_rgb_sp_name;
 
         if (!init || !(HL_TABLE()[idx].sg_set & SG_GUI)) {
           if (!init) {
@@ -6957,8 +6957,8 @@ void do_highlight(const char *line, const bool forceit, const bool init)
           if (*namep == NULL || STRCMP(*namep, arg) != 0) {
             xfree(*namep);
             if (strcmp(arg, "NONE") != 0) {
-              *namep = (char_u *)xstrdup(arg);
-              HL_TABLE()[idx].sg_rgb_sp = name_to_color((char_u *)arg);
+              *namep = xstrdup(arg);
+              HL_TABLE()[idx].sg_rgb_sp = name_to_color(arg);
             } else {
               *namep = NULL;
               HL_TABLE()[idx].sg_rgb_sp = -1;
@@ -7152,13 +7152,32 @@ static void highlight_list_one(const int id)
     msg_outtrans(HL_TABLE()[HL_TABLE()[id - 1].sg_link - 1].sg_name);
   }
 
-  if (!didh)
-    highlight_list_arg(id, didh, LIST_STRING, 0, (char_u *)"cleared", "");
+  if (!didh) {
+    highlight_list_arg(id, didh, LIST_STRING, 0, "cleared", "");
+  }
   if (p_verbose > 0) {
     last_set_msg(sgp->sg_script_ctx);
   }
 }
 
+Dictionary get_global_hl_defs(void)
+{
+  Dictionary rv = ARRAY_DICT_INIT;
+  for (int i = 1; i <= highlight_ga.ga_len && !got_int; i++) {
+    Dictionary attrs = ARRAY_DICT_INIT;
+    struct hl_group *h = &HL_TABLE()[i - 1];
+    if (h->sg_attr > 0) {
+      attrs = hlattrs2dict(syn_attr2entry(h->sg_attr), true);
+    } else if (h->sg_link > 0) {
+      const char *link = (const char *)HL_TABLE()[h->sg_link - 1].sg_name;
+      PUT(attrs, "link", STRING_OBJ(cstr_to_string(link)));
+    }
+    PUT(rv, (const char *)h->sg_name, DICTIONARY_OBJ(attrs));
+  }
+
+  return rv;
+}
+
 /// Outputs a highlight when doing ":hi MyHighlight"
 ///
 /// @param type one of \ref LIST_XXX
@@ -7166,15 +7185,15 @@ static void highlight_list_one(const int id)
 /// @param sarg string used if \p type == LIST_STRING
 static bool highlight_list_arg(
     const int id, bool didh, const int type, int iarg,
-    char_u *const sarg, const char *const name)
+    char *const sarg, const char *const name)
 {
-  char_u buf[100];
+  char buf[100];
 
   if (got_int) {
     return false;
   }
   if (type == LIST_STRING ? (sarg != NULL) : (iarg != 0)) {
-    char_u *ts = buf;
+    char *ts = buf;
     if (type == LIST_INT) {
       snprintf((char *)buf, sizeof(buf), "%d", iarg - 1);
     } else if (type == LIST_STRING) {
@@ -7191,15 +7210,15 @@ static bool highlight_list_arg(
       }
     }
 
-    (void)syn_list_header(didh, (int)(vim_strsize(ts) + STRLEN(name) + 1), id,
-                          false);
+    (void)syn_list_header(didh, (int)(vim_strsize((char_u *)ts) + STRLEN(name)
+                                      + 1), id, false);
     didh = true;
     if (!got_int) {
       if (*name != NUL) {
         MSG_PUTS_ATTR(name, HL_ATTR(HLF_D));
         MSG_PUTS_ATTR("=", HL_ATTR(HLF_D));
       }
-      msg_outtrans(ts);
+      msg_outtrans((char_u *)ts);
     }
   }
   return didh;
@@ -7378,7 +7397,7 @@ static void set_hl_attr(int idx)
   at_en.rgb_sp_color = sgp->sg_rgb_sp_name ? sgp->sg_rgb_sp : -1;
   at_en.hl_blend = sgp->sg_blend;
 
-  sgp->sg_attr = hl_get_syn_attr(idx+1, at_en);
+  sgp->sg_attr = hl_get_syn_attr(0, idx+1, at_en);
 
   // a cursor style uses this syn_id, make sure its attribute is updated.
   if (cursor_mode_uses_syn_id(idx+1)) {
@@ -7541,11 +7560,17 @@ int syn_id2attr(int hl_id)
   struct hl_group     *sgp;
 
   hl_id = syn_get_final_id(hl_id);
-  sgp = &HL_TABLE()[hl_id - 1];             /* index is ID minus one */
+  int attr = ns_get_hl(-1, hl_id, false);
+  if (attr >= 0) {
+    return attr;
+  }
+  sgp = &HL_TABLE()[hl_id - 1];  // index is ID minus one
   return sgp->sg_attr;
 }
 
 
+
+
 /*
  * Translate a group ID to the final group ID (following links).
  */
@@ -7562,9 +7587,22 @@ int syn_get_final_id(int hl_id)
    * Look out for loops!  Break after 100 links.
    */
   for (count = 100; --count >= 0; ) {
-    sgp = &HL_TABLE()[hl_id - 1];           /* index is ID minus one */
-    if (sgp->sg_link == 0 || sgp->sg_link > highlight_ga.ga_len)
+    // ACHTUNG: when using "tmp" attribute (no link) the function might be
+    // called twice. it needs be smart enough to remember attr only to
+    // syn_id2attr time
+    int check = ns_get_hl(-1, hl_id, true);
+    if (check == 0) {
+      return 0;  // how dare! it broke the link!
+    } else if (check > 0) {
+      hl_id = check;
+      continue;
+    }
+
+
+    sgp = &HL_TABLE()[hl_id - 1];  // index is ID minus one
+    if (sgp->sg_link == 0 || sgp->sg_link > highlight_ga.ga_len) {
       break;
+    }
     hl_id = sgp->sg_link;
   }
 
@@ -8494,7 +8532,7 @@ color_name_table_T color_name_table[] = {
 ///
 /// @param[in] name string value to convert to RGB
 /// return the hex value or -1 if could not find a correct value
-RgbValue name_to_color(const char_u *name)
+RgbValue name_to_color(const char *name)
 {
 
   if (name[0] == '#' && isxdigit(name[1]) && isxdigit(name[2])
diff --git a/src/nvim/tag.c b/src/nvim/tag.c
index 81d1ef4c9f..c6b1a0d04c 100644
--- a/src/nvim/tag.c
+++ b/src/nvim/tag.c
@@ -2903,7 +2903,7 @@ static int jumpto_tag(
         && curwin != curwin_save && win_valid(curwin_save)) {
       /* Return cursor to where we were */
       validate_cursor();
-      redraw_later(VALID);
+      redraw_later(curwin, VALID);
       win_enter(curwin_save, true);
     }
 
diff --git a/src/nvim/terminal.c b/src/nvim/terminal.c
index 52d3eef810..39e2ca6171 100644
--- a/src/nvim/terminal.c
+++ b/src/nvim/terminal.c
@@ -233,7 +233,7 @@ Terminal *terminal_open(TerminalOptions opts)
     snprintf(var, sizeof(var), "terminal_color_%d", i);
     char *name = get_config_string(var);
     if (name) {
-      color_val = name_to_color((uint8_t *)name);
+      color_val = name_to_color(name);
       xfree(name);
 
       if (color_val != -1) {
@@ -1060,7 +1060,7 @@ static bool send_mouse_event(Terminal *term, int c)
     curwin->w_redr_status = true;
     curwin = save_curwin;
     curbuf = curwin->w_buffer;
-    redraw_win_later(mouse_win, NOT_VALID);
+    redraw_later(mouse_win, NOT_VALID);
     invalidate_terminal(term, -1, -1);
     // Only need to exit focus if the scrolled window is the terminal window
     return mouse_win == curwin;
diff --git a/src/nvim/types.h b/src/nvim/types.h
index a3d87f35ca..17f7e16740 100644
--- a/src/nvim/types.h
+++ b/src/nvim/types.h
@@ -21,7 +21,7 @@ typedef int handle_T;
 // absent callback etc.
 typedef int LuaRef;
 
-typedef uint64_t NS;
+typedef handle_T NS;
 
 typedef struct expand expand_T;
 
diff --git a/src/nvim/ui_compositor.c b/src/nvim/ui_compositor.c
index e582d8f859..325ad31eaf 100644
--- a/src/nvim/ui_compositor.c
+++ b/src/nvim/ui_compositor.c
@@ -26,6 +26,7 @@
 #include "nvim/screen.h"
 #include "nvim/syntax.h"
 #include "nvim/api/private/helpers.h"
+#include "nvim/lua/executor.h"
 #include "nvim/os/os.h"
 
 #ifdef INCLUDE_GENERATED_DECLARATIONS
diff --git a/src/nvim/undo.c b/src/nvim/undo.c
index 6c5a6cdb46..a8b8f7aa50 100644
--- a/src/nvim/undo.c
+++ b/src/nvim/undo.c
@@ -2455,7 +2455,7 @@ static void u_undo_end(
   {
     FOR_ALL_WINDOWS_IN_TAB(wp, curtab) {
       if (wp->w_buffer == curbuf && wp->w_p_cole > 0) {
-        redraw_win_later(wp, NOT_VALID);
+        redraw_later(wp, NOT_VALID);
       }
     }
   }
diff --git a/src/nvim/window.c b/src/nvim/window.c
index 4931221e7a..863c1a7556 100644
--- a/src/nvim/window.c
+++ b/src/nvim/window.c
@@ -606,7 +606,7 @@ win_T *win_new_float(win_T *wp, FloatConfig fconfig, Error *err)
 
   win_config_float(wp, fconfig);
   wp->w_pos_changed = true;
-  redraw_win_later(wp, VALID);
+  redraw_later(wp, VALID);
   return wp;
 }
 
@@ -679,7 +679,7 @@ void win_config_float(win_T *wp, FloatConfig fconfig)
   wp->w_pos_changed = true;
   if (change_external) {
     wp->w_hl_needs_update = true;
-    redraw_win_later(wp, NOT_VALID);
+    redraw_later(wp, NOT_VALID);
   }
 }
 
@@ -764,7 +764,7 @@ static void ui_ext_win_position(win_T *wp)
       wp->w_grid.focusable = wp->w_float_config.focusable;
       if (!valid) {
         wp->w_grid.valid = false;
-        redraw_win_later(wp, NOT_VALID);
+        redraw_later(wp, NOT_VALID);
       }
     }
   } else {
@@ -1492,8 +1492,8 @@ int win_split_ins(int size, int flags, win_T *new_wp, int dir)
 
   // Both windows need redrawing.  Update all status lines, in case they
   // show something related to the window count or position.
-  redraw_win_later(wp, NOT_VALID);
-  redraw_win_later(oldwin, NOT_VALID);
+  redraw_later(wp, NOT_VALID);
+  redraw_later(oldwin, NOT_VALID);
   status_redraw_all();
 
   if (need_status) {
@@ -1823,8 +1823,8 @@ static void win_exchange(long Prenum)
   (void)win_comp_pos();                 /* recompute window positions */
 
   win_enter(wp, true);
-  redraw_later(NOT_VALID);
-  redraw_win_later(wp, NOT_VALID);
+  redraw_later(curwin, NOT_VALID);
+  redraw_later(wp, NOT_VALID);
 }
 
 // rotate windows: if upwards true the second window becomes the first one
@@ -1996,8 +1996,8 @@ void win_move_after(win_T *win1, win_T *win2)
     win_append(win2, win1);
     frame_append(win2->w_frame, win1->w_frame);
 
-    (void)win_comp_pos();       /* recompute w_winrow for all windows */
-    redraw_later(NOT_VALID);
+    (void)win_comp_pos();  // recompute w_winrow for all windows
+    redraw_later(curwin, NOT_VALID);
   }
   win_enter(win1, false);
 
@@ -3635,7 +3635,7 @@ void curwin_init(void)
 
 void win_init_empty(win_T *wp)
 {
-  redraw_win_later(wp, NOT_VALID);
+  redraw_later(wp, NOT_VALID);
   wp->w_lines_valid = 0;
   wp->w_cursor.lnum = 1;
   wp->w_curswant = wp->w_cursor.col = 0;
@@ -4587,10 +4587,11 @@ static void win_enter_ext(win_T *wp, bool undo_sync, int curwin_invalid,
   }
 
   maketitle();
-  curwin->w_redr_status = TRUE;
-  redraw_tabline = TRUE;
-  if (restart_edit)
-    redraw_later(VALID);        /* causes status line redraw */
+  curwin->w_redr_status = true;
+  redraw_tabline = true;
+  if (restart_edit) {
+    redraw_later(curwin, VALID);  // causes status line redraw
+  }
 
   if (HL_ATTR(HLF_INACTIVE)
       || (prevwin && prevwin->w_hl_ids[HLF_INACTIVE])
@@ -5056,7 +5057,7 @@ static void frame_comp_pos(frame_T *topfrp, int *row, int *col)
       /* position changed, redraw */
       wp->w_winrow = *row;
       wp->w_wincol = *col;
-      redraw_win_later(wp, NOT_VALID);
+      redraw_later(wp, NOT_VALID);
       wp->w_redr_status = true;
       wp->w_pos_changed = true;
     }
@@ -5109,7 +5110,7 @@ void win_setheight_win(int height, win_T *win)
   if (win->w_floating) {
     win->w_float_config.height = height;
     win_config_float(win, win->w_float_config);
-    redraw_win_later(win, NOT_VALID);
+    redraw_later(win, NOT_VALID);
   } else {
     frame_setheight(win->w_frame, height + win->w_status_height);
 
@@ -5312,7 +5313,7 @@ void win_setwidth_win(int width, win_T *wp)
   if (wp->w_floating) {
     wp->w_float_config.width = width;
     win_config_float(wp, wp->w_float_config);
-    redraw_win_later(wp, NOT_VALID);
+    redraw_later(wp, NOT_VALID);
   } else {
     frame_setwidth(wp->w_frame, width + wp->w_vsep_width);
 
@@ -5845,8 +5846,8 @@ void scroll_to_fraction(win_T *wp, int prev_height)
   }
 
   win_comp_scroll(wp);
-  redraw_win_later(wp, SOME_VALID);
-  wp->w_redr_status = TRUE;
+  redraw_later(wp, SOME_VALID);
+  wp->w_redr_status = true;
   invalidate_botline_win(wp);
 }
 
@@ -5885,7 +5886,7 @@ void win_set_inner_size(win_T *wp)
     if (!exiting) {
       scroll_to_fraction(wp, prev_height);
     }
-    redraw_win_later(wp, NOT_VALID);  // SOME_VALID??
+    redraw_later(wp, NOT_VALID);  // SOME_VALID??
   }
 
   if (width != wp->w_width_inner) {
@@ -5897,7 +5898,7 @@ void win_set_inner_size(win_T *wp)
       update_topline();
       curs_columns(true);  // validate w_wrow
     }
-    redraw_win_later(wp, NOT_VALID);
+    redraw_later(wp, NOT_VALID);
   }
 
   if (wp->w_buffer->terminal) {
@@ -6741,7 +6742,7 @@ int match_add(win_T *wp, const char *const grp, const char *const pat,
     prev->next = m;
   m->next = cur;
 
-  redraw_win_later(wp, rtype);
+  redraw_later(wp, rtype);
   return id;
 
 fail:
@@ -6799,7 +6800,7 @@ int match_delete(win_T *wp, int id, int perr)
     rtype = VALID;
   }
   xfree(cur);
-  redraw_win_later(wp, rtype);
+  redraw_later(wp, rtype);
   return 0;
 }
 
@@ -6817,7 +6818,7 @@ void clear_matches(win_T *wp)
     xfree(wp->w_match_head);
     wp->w_match_head = m;
   }
-  redraw_win_later(wp, SOME_VALID);
+  redraw_later(wp, SOME_VALID);
 }
 
 /*
diff --git a/test/functional/helpers.lua b/test/functional/helpers.lua
index 0bd378d832..d85a6a3cfe 100644
--- a/test/functional/helpers.lua
+++ b/test/functional/helpers.lua
@@ -751,6 +751,14 @@ module.curbufmeths = module.create_callindex(module.curbuf)
 module.curwinmeths = module.create_callindex(module.curwin)
 module.curtabmeths = module.create_callindex(module.curtab)
 
+function module.exec(code)
+  return module.meths.exec(code, false)
+end
+
+function module.exec_capture(code)
+  return module.meths.exec(code, true)
+end
+
 function module.exec_lua(code, ...)
   return module.meths.exec_lua(code, {...})
 end
diff --git a/test/functional/ui/decorations_spec.lua b/test/functional/ui/decorations_spec.lua
index 304c5aecb1..4182090732 100644
--- a/test/functional/ui/decorations_spec.lua
+++ b/test/functional/ui/decorations_spec.lua
@@ -5,20 +5,32 @@ local clear = helpers.clear
 local feed = helpers.feed
 local insert = helpers.insert
 local exec_lua = helpers.exec_lua
+local exec = helpers.exec
 local expect_events = helpers.expect_events
+local meths = helpers.meths
 
-describe('decorations provider', function()
+describe('decorations providers', function()
   local screen
   before_each(function()
     clear()
     screen = Screen.new(40, 8)
     screen:attach()
-    screen:set_default_attr_ids({
-      [1] = {bold=true, foreground=Screen.colors.Blue},
-    })
+    screen:set_default_attr_ids {
+      [1] = {bold=true, foreground=Screen.colors.Blue};
+      [2] = {foreground = Screen.colors.Grey100, background = Screen.colors.Red};
+      [3] = {foreground = Screen.colors.Brown};
+      [4] = {foreground = Screen.colors.Blue1};
+      [5] = {foreground = Screen.colors.Magenta};
+      [6] = {bold = true, foreground = Screen.colors.Brown};
+      [7] = {background = Screen.colors.Gray90};
+      [8] = {bold = true, reverse = true};
+      [9] = {reverse = true};
+      [10] = {italic = true, background = Screen.colors.Magenta};
+      [11] = {foreground = Screen.colors.Red, background = tonumber('0x005028')};
+    }
   end)
 
-  local mudholland = [[
+  local mulholland = [[
     // just to see if there was an accident
     // on Mulholland Drive
     try_start();
@@ -28,21 +40,21 @@ describe('decorations provider', function()
     restore_buffer(&save_buf); ]]
 
   local function setup_provider(code)
-    exec_lua ([[
+    return exec_lua ([[
       local a = vim.api
-      test1 = a.nvim_create_namespace "test1"
+      _G.ns1 = a.nvim_create_namespace "ns1"
     ]] .. (code or [[
       beamtrace = {}
-      function on_do(kind, ...)
+      local function on_do(kind, ...)
         table.insert(beamtrace, {kind, ...})
       end
     ]]) .. [[
-      a.nvim_set_decoration_provider(
-        test1, {
+      a.nvim_set_decoration_provider(_G.ns1, {
         on_start = on_do; on_buf = on_do;
         on_win = on_do; on_line = on_do;
         on_end = on_do;
       })
+      return _G.ns1
     ]])
   end
 
@@ -51,8 +63,8 @@ describe('decorations provider', function()
     expect_events(expected, actual, "beam trace")
   end
 
-  it('leaves a trace', function()
-    insert(mudholland)
+  it('leave a trace', function()
+    insert(mulholland)
 
     setup_provider()
 
@@ -99,11 +111,12 @@ describe('decorations provider', function()
     }
   end)
 
-  it('single provider', function()
-    insert(mudholland)
+  it('can have single provider', function()
+    insert(mulholland)
     setup_provider [[
       local hl = a.nvim_get_hl_id_by_name "ErrorMsg"
-      function do_it(event, ...)
+      local test_ns = a.nvim_create_namespace "mulholland"
+      function on_do(event, ...)
         if event == "line" then
           local win, buf, line = ...
           a.nvim_buf_set_extmark(buf, test_ns, line, line,
@@ -114,5 +127,104 @@ describe('decorations provider', function()
         end
       end
     ]]
+
+    screen:expect{grid=[[
+      {2:/}/ just to see if there was an accident |
+      /{2:/} on Mulholland Drive                  |
+      tr{2:y}_start();                            |
+      buf{2:r}ef_T save_buf;                      |
+      swit{2:c}h_buffer(&save_buf, buf);          |
+      posp {2:=} getmark(mark, false);            |
+      restor{2:e}_buffer(&save_buf);^              |
+                                              |
+    ]]}
+  end)
+
+  it('can predefine highlights', function()
+    screen:try_resize(40, 16)
+    insert(mulholland)
+    exec [[
+      3
+      set ft=c
+      syntax on
+      set number cursorline
+      split
+    ]]
+    local ns1 = setup_provider()
+
+    for k,v in pairs {
+      LineNr = {italic=true, bg="Magenta"};
+      Comment = {fg="#FF0000", bg = 80*256+40};
+      CursorLine = {link="ErrorMsg"};
+    } do meths.set_hl(ns1, k, v) end
+
+    screen:expect{grid=[[
+      {3:  1 }{4:// just to see if there was an accid}|
+      {3:    }{4:ent}                                 |
+      {3:  2 }{4:// on Mulholland Drive}              |
+      {6:  3 }{7:^try_start();                        }|
+      {3:  4 }bufref_T save_buf;                  |
+      {3:  5 }switch_buffer(&save_buf, buf);      |
+      {3:  6 }posp = getmark(mark, {5:false});        |
+      {8:[No Name] [+]                           }|
+      {3:  2 }{4:// on Mulholland Drive}              |
+      {6:  3 }{7:try_start();                        }|
+      {3:  4 }bufref_T save_buf;                  |
+      {3:  5 }switch_buffer(&save_buf, buf);      |
+      {3:  6 }posp = getmark(mark, {5:false});        |
+      {3:  7 }restore_buffer(&save_buf);          |
+      {9:[No Name] [+]                           }|
+                                              |
+    ]]}
+
+    meths.set_hl_ns(ns1)
+    screen:expect{grid=[[
+      {10:  1 }{11:// just to see if there was an accid}|
+      {10:    }{11:ent}                                 |
+      {10:  2 }{11:// on Mulholland Drive}              |
+      {6:  3 }{2:^try_start();                        }|
+      {10:  4 }bufref_T save_buf;                  |
+      {10:  5 }switch_buffer(&save_buf, buf);      |
+      {10:  6 }posp = getmark(mark, {5:false});        |
+      {8:[No Name] [+]                           }|
+      {10:  2 }{11:// on Mulholland Drive}              |
+      {6:  3 }{2:try_start();                        }|
+      {10:  4 }bufref_T save_buf;                  |
+      {10:  5 }switch_buffer(&save_buf, buf);      |
+      {10:  6 }posp = getmark(mark, {5:false});        |
+      {10:  7 }restore_buffer(&save_buf);          |
+      {9:[No Name] [+]                           }|
+                                              |
+    ]]}
+
+    exec_lua [[
+      local a = vim.api
+      local thewin = a.nvim_get_current_win()
+      local ns2 = a.nvim_create_namespace 'ns2'
+      a.nvim_set_decoration_provider (ns2, {
+        on_win = function (_, win, buf)
+          a.nvim_set_hl_ns(win == thewin and _G.ns1 or ns2)
+        end;
+      })
+    ]]
+    screen:expect{grid=[[
+      {10:  1 }{11:// just to see if there was an accid}|
+      {10:    }{11:ent}                                 |
+      {10:  2 }{11:// on Mulholland Drive}              |
+      {6:  3 }{2:^try_start();                        }|
+      {10:  4 }bufref_T save_buf;                  |
+      {10:  5 }switch_buffer(&save_buf, buf);      |
+      {10:  6 }posp = getmark(mark, {5:false});        |
+      {8:[No Name] [+]                           }|
+      {3:  2 }{4:// on Mulholland Drive}              |
+      {6:  3 }{7:try_start();                        }|
+      {3:  4 }bufref_T save_buf;                  |
+      {3:  5 }switch_buffer(&save_buf, buf);      |
+      {3:  6 }posp = getmark(mark, {5:false});        |
+      {3:  7 }restore_buffer(&save_buf);          |
+      {9:[No Name] [+]                           }|
+                                              |
+    ]]}
+
   end)
 end)
diff --git a/test/functional/ui/screen.lua b/test/functional/ui/screen.lua
index bf979e89f4..8fa9fcc42f 100644
--- a/test/functional/ui/screen.lua
+++ b/test/functional/ui/screen.lua
@@ -1289,7 +1289,7 @@ local function fmt_ext_state(name, state)
     for k,v in pairs(state) do
       str = (str.."  ["..k.."] = {win = {id = "..v.win.id.."}, topline = "
              ..v.topline..", botline = "..v.botline..", curline = "..v.curline
-             ..", curcol = "..v.curcol.."},\n")
+             ..", curcol = "..v.curcol.."};\n")
     end
     return str .. "}"
   else
@@ -1316,7 +1316,7 @@ function Screen:print_snapshot(attrs, ignore)
         dict = "{"..self:_pprint_attrs(a).."}"
       end
       local keyval = (type(i) == "number") and "["..tostring(i).."]" or i
-      table.insert(attrstrs, "  "..keyval.." = "..dict..",")
+      table.insert(attrstrs, "  "..keyval.." = "..dict..";")
     end
     attrstr = (", attr_ids={\n"..table.concat(attrstrs, "\n").."\n}")
   end