5 files changed, 99 insertions, 3 deletions
diff --git a/src/nvim/lua/converter.c b/src/nvim/lua/converter.c
index b6792a5a97..8a702ddd60 100644
--- a/src/nvim/lua/converter.c
+++ b/src/nvim/lua/converter.c
@@ -1242,7 +1242,12 @@ LuaRef nlua_pop_LuaRef(lua_State *const lstate, Error *err)
   FUNC_ATTR_NONNULL_ALL FUNC_ATTR_WARN_UNUSED_RESULT \
   { \
     type ret; \
-    ret = (type)lua_tonumber(lstate, -1); \
+    if (lua_type(lstate, -1) != LUA_TNUMBER) { \
+      api_set_error(err, kErrorTypeValidation, "Expected Lua number"); \
+      ret = (type)-1; \
+    } else { \
+      ret = (type)lua_tonumber(lstate, -1); \
+    } \
     lua_pop(lstate, 1); \
     return ret; \
   }
diff --git a/src/nvim/lua/executor.c b/src/nvim/lua/executor.c
index 107ff22913..c814974fe7 100644
--- a/src/nvim/lua/executor.c
+++ b/src/nvim/lua/executor.c
@@ -18,6 +18,7 @@
 #include "nvim/event/loop.h"
 #include "nvim/event/time.h"
 #include "nvim/ex_cmds2.h"
+#include "nvim/ex_docmd.h"
 #include "nvim/ex_getln.h"
 #include "nvim/extmark.h"
 #include "nvim/func_attr.h"
@@ -433,6 +434,15 @@ static int nlua_state_init(lua_State *const lstate) FUNC_ATTR_NONNULL_ALL
     // [package, loaded, module]
     lua_setfield(lstate, -2, "vim.F");  // [package, loaded]
 
+    code = (char *)&lua_filetype_module[0];
+    if (luaL_loadbuffer(lstate, code, sizeof(lua_filetype_module) - 1, "@vim/filetype.lua")
+        || nlua_pcall(lstate, 0, 1)) {
+      nlua_error(lstate, _("E5106: Error while creating vim.filetype module: %.*s"));
+      return 1;
+    }
+    // [package, loaded, module]
+    lua_setfield(lstate, -2, "vim.filetype");  // [package, loaded]
+
     lua_pop(lstate, 2);  // []
   }
 
@@ -914,6 +924,24 @@ void nlua_typval_call(const char *str, size_t len, typval_T *const args, int arg
   }
 }
 
+void nlua_call_user_expand_func(expand_T *xp, typval_T *ret_tv)
+  FUNC_ATTR_NONNULL_ALL
+{
+  lua_State *const lstate = global_lstate;
+
+  nlua_pushref(lstate, xp->xp_luaref);
+  lua_pushstring(lstate, (char *)xp->xp_pattern);
+  lua_pushstring(lstate, (char *)xp->xp_line);
+  lua_pushinteger(lstate, xp->xp_col);
+
+  if (nlua_pcall(lstate, 3, 1)) {
+    nlua_error(lstate, _("E5108: Error executing Lua function: %.*s"));
+    return;
+  }
+
+  nlua_pop_typval(lstate, ret_tv);
+}
+
 static void nlua_typval_exec(const char *lcmd, size_t lcmd_len, const char *name,
                              typval_T *const args, int argcount, bool special, typval_T *ret_tv)
 {
@@ -1096,11 +1124,23 @@ void ex_lua(exarg_T *const eap)
   FUNC_ATTR_NONNULL_ALL
 {
   size_t len;
-  char *const code = script_get(eap, &len);
+  char *code = script_get(eap, &len);
   if (eap->skip) {
     xfree(code);
     return;
   }
+  // When =expr is used transform it to print(vim.inspect(expr))
+  if (code[0] == '=') {
+    len += sizeof("print(vim.inspect())") - sizeof("=");
+    // code_buf needs to be 1 char larger then len for null byte in the end.
+    // lua nlua_typval_exec doesn't expect null terminated string so len
+    // needs to end before null byte.
+    char *code_buf = xmallocz(len);
+    vim_snprintf(code_buf, len+1, "print(vim.inspect(%s))", code+1);
+    xfree(code);
+    code = code_buf;
+  }
+
   nlua_typval_exec(code, len, ":lua", NULL, 0, false, NULL);
 
   xfree(code);
@@ -1432,3 +1472,48 @@ void nlua_execute_on_key(int c)
 #endif
 }
 
+void nlua_do_ucmd(ucmd_T *cmd, exarg_T *eap)
+{
+  lua_State *const lstate = global_lstate;
+
+  nlua_pushref(lstate, cmd->uc_luaref);
+
+  lua_newtable(lstate);
+  lua_pushboolean(lstate, eap->forceit == 1);
+  lua_setfield(lstate, -2, "bang");
+
+  lua_pushinteger(lstate, eap->line1);
+  lua_setfield(lstate, -2, "line1");
+
+  lua_pushinteger(lstate, eap->line2);
+  lua_setfield(lstate, -2, "line2");
+
+  lua_pushstring(lstate, (const char *)eap->arg);
+  lua_setfield(lstate, -2, "args");
+
+  lua_pushstring(lstate, (const char *)&eap->regname);
+  lua_setfield(lstate, -2, "reg");
+
+  lua_pushinteger(lstate, eap->addr_count);
+  lua_setfield(lstate, -2, "range");
+
+  if (eap->addr_count > 0) {
+    lua_pushinteger(lstate, eap->line2);
+  } else {
+    lua_pushinteger(lstate, cmd->uc_def);
+  }
+  lua_setfield(lstate, -2, "count");
+
+  // The size of this buffer is chosen empirically to be large enough to hold
+  // every possible modifier (with room to spare). If the list of possible
+  // modifiers grows this may need to be updated.
+  char buf[200] = { 0 };
+  (void)uc_mods(buf);
+  lua_pushstring(lstate, buf);
+  lua_setfield(lstate, -2, "mods");
+
+  if (nlua_pcall(lstate, 1, 0)) {
+    nlua_error(lstate, _("Error executing Lua callback: %.*s"));
+  }
+}
+
diff --git a/src/nvim/lua/executor.h b/src/nvim/lua/executor.h
index a1f66bd02b..bf78f7ec5e 100644
--- a/src/nvim/lua/executor.h
+++ b/src/nvim/lua/executor.h
@@ -7,6 +7,7 @@
 #include "nvim/api/private/defs.h"
 #include "nvim/eval/typval.h"
 #include "nvim/ex_cmds_defs.h"
+#include "nvim/ex_docmd.h"
 #include "nvim/func_attr.h"
 #include "nvim/lua/converter.h"
 
diff --git a/src/nvim/lua/spell.c b/src/nvim/lua/spell.c
index b84124bc19..3a63f61200 100644
--- a/src/nvim/lua/spell.c
+++ b/src/nvim/lua/spell.c
@@ -1,3 +1,5 @@
+// This is an open source non-commercial project. Dear PVS-Studio, please check
+// it. PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
 
 #include <lua.h>
 #include <lauxlib.h>
diff --git a/src/nvim/lua/vim.lua b/src/nvim/lua/vim.lua
index c1a1e7f162..6ef46ee844 100644
--- a/src/nvim/lua/vim.lua
+++ b/src/nvim/lua/vim.lua
@@ -40,6 +40,9 @@ assert(vim)
 vim.inspect = package.loaded['vim.inspect']
 assert(vim.inspect)
 
+vim.filetype = package.loaded['vim.filetype']
+assert(vim.filetype)
+
 local pathtrails = {}
 vim._so_trails = {}
 for s in  (package.cpath..';'):gmatch('[^;]*;') do
@@ -424,7 +427,7 @@ end
 --- Without a runtime, writes to :Messages
 ---@see :help nvim_notify
 ---@param msg string Content of the notification to show to the user
----@param log_level number|nil enum from vim.log.levels
+---@param log_level number|nil enum from |vim.log.levels|
 ---@param opts table|nil additional options (timeout, etc)
 function vim.notify(msg, log_level, opts) -- luacheck: no unused
   if log_level == vim.log.levels.ERROR then