[extregs] implement tab completion for ~ menu.extregs

5 files changed, 52 insertions, 1 deletions

diff --git a/src/nvim/cmdexpand.c b/src/nvim/cmdexpand.c
index 040a18f889..50f795c590 100644
--- a/src/nvim/cmdexpand.c
+++ b/src/nvim/cmdexpand.c
@@ -1508,6 +1508,14 @@ void set_expand_context(expand_T *xp)
     return;
   }
 
+  if (ccline->cmdfirstc == '~') {
+    xp->xp_context = EXPAND_EXTREGS;
+    xp->xp_pattern = ccline->cmdbuff;
+    xp->xp_line = ccline->cmdbuff;
+    xp->xp_col = ccline->cmdpos;
+    return;
+  }
+
   // Only handle ':', '>', or '=' command-lines, or expression input
   if (ccline->cmdfirstc != ':'
       && ccline->cmdfirstc != '>' && ccline->cmdfirstc != '='
@@ -2970,6 +2978,11 @@ static char *get_arg1_from_lua(char *lua, expand_T *xp, int idx)
   return NULL;
 }
 
+static char* get_extreg_arg(expand_T *xp, int idx) {
+  char* ret = get_arg1_from_lua("return vim._extregs.get_provider_names(...)", xp, idx);
+  return ret;
+}
+
 /// Completion for the |:marks| command. Given to ExpandGeneric().
 /// @param[in] xp  Expandy thing 🤷
 /// @param[in] idx  Index of the item.
@@ -3057,6 +3070,7 @@ static int ExpandOther(char *pat, expand_T *xp, regmatch_T *rmp, char ***matches
     { EXPAND_LSP, get_lsp_arg, true, false },
     { EXPAND_PACKDEL, get_packdel_arg, true, false },
     { EXPAND_PACKUPDATE, get_packupdate_arg, true, false },
+    { EXPAND_EXTREGS, get_extreg_arg, true, false },
   };
   int ret = FAIL;
 
diff --git a/src/nvim/cmdexpand_defs.h b/src/nvim/cmdexpand_defs.h
index 9fee7fd06f..5afc2f77e2 100644
--- a/src/nvim/cmdexpand_defs.h
+++ b/src/nvim/cmdexpand_defs.h
@@ -134,6 +134,7 @@ enum {
   EXPAND_PACKDEL,
   EXPAND_PACKUPDATE,
   EXPAND_MARKS,
+  EXPAND_EXTREGS,
 };
 
 /// Type used by ExpandGeneric()
diff --git a/src/nvim/extreg.c b/src/nvim/extreg.c
index b416ac8111..455a8e24e5 100644
--- a/src/nvim/extreg.c
+++ b/src/nvim/extreg.c
@@ -855,3 +855,36 @@ int nlua_extregs_get_provider(lua_State *lstate)
   lua_pushlightuserdata(lstate, (void *)prov);
   return 1;
 }
+
+/// Lua: vim._extregs.get_provider_names()
+/// Returns a table of all registered extreg provider names
+int nlua_extregs_get_provider_names(lua_State *lstate)
+{
+  hash_lock(&extreg_providers);
+  
+  // First, count the registered providers
+  size_t count = 0;
+  HASHTAB_ITER(&extreg_providers, hi, {
+    extreg_provider_t *prov = HASH_ITEM_TO_EXTREG_PROVIDER(hi);
+    if (prov->registered) {
+      count++;
+    }
+  });
+  
+  // Create table with pre-allocated size
+  lua_createtable(lstate, (int)count, 0);
+  
+  // Now fill the table
+  size_t idx = 1;
+  HASHTAB_ITER(&extreg_providers, hi, {
+    extreg_provider_t *prov = HASH_ITEM_TO_EXTREG_PROVIDER(hi);
+    if (prov->registered && idx <= count) {
+      lua_pushstring(lstate, prov->name);
+      lua_rawseti(lstate, -2, (int)idx++);
+    }
+  });
+  
+  hash_unlock(&extreg_providers);
+  
+  return 1;  // return the table
+}
diff --git a/src/nvim/extreg.h b/src/nvim/extreg.h
index 5dc8fec367..4137d17e8b 100644
--- a/src/nvim/extreg.h
+++ b/src/nvim/extreg.h
@@ -70,3 +70,4 @@ extern int nlua_extregs_unbind(lua_State *lstate);
 extern int nlua_extregs_is_alias(lua_State *lstate);
 extern int nlua_extregs_get_provider_name_for_alias(lua_State *lstate);
 extern int nlua_extregs_get_provider(lua_State *lstate);
+extern int nlua_extregs_get_provider_names(lua_State *lstate);
diff --git a/src/nvim/lua/executor.c b/src/nvim/lua/executor.c
index aa159ef94d..204c5d53a8 100644
--- a/src/nvim/lua/executor.c
+++ b/src/nvim/lua/executor.c
@@ -760,7 +760,7 @@ static void nlua_common_vim_init(lua_State *lstate, bool is_thread)
   lua_setfield(lstate, -2, "_empty_dict_mt");
 
   // vim._extregs
-  lua_createtable(lstate, 0, 8);
+  lua_createtable(lstate, 0, 9);
   lua_pushcfunction(lstate, &nlua_extregs_register);
   lua_setfield(lstate, -2, "register");
   lua_pushcfunction(lstate, &nlua_extregs_unregister);
@@ -775,6 +775,8 @@ static void nlua_common_vim_init(lua_State *lstate, bool is_thread)
   lua_setfield(lstate, -2, "get_provider_name_for_alias");
   lua_pushcfunction(lstate, &nlua_extregs_get_provider);
   lua_setfield(lstate, -2, "get_provider");
+  lua_pushcfunction(lstate, &nlua_extregs_get_provider_names);
+  lua_setfield(lstate, -2, "get_provider_names");
   lua_setfield(lstate, -2, "_extregs");
 
   // vim.uv