Add support for setting status bar text from Lua

automation/v4-docs/misc.txt

@@ -40,3 +40,11 @@ Returns: 2 values, all numbers.
   2. End of the selection, in milliseconds.
 
 ---
+
+Setting the main frame's status bar text
+
+function aegisub.set_status_bar_text(text)
+
+Returns: 0 values
+
+---

src/auto4_lua.cpp

@@ -44,6 +44,7 @@
 #include "audio_timing.h"
 #include "command/command.h"
 #include "compat.h"
+#include "frame_main.h"
 #include "include/aegisub/context.h"
 #include "options.h"
 #include "project.h"
@@ -52,6 +53,7 @@
 #include "video_controller.h"
 #include "utils.h"
 
+#include <libaegisub/dispatch.h>
 #include <libaegisub/format.h>
 #include <libaegisub/lua/ffi.h>
 #include <libaegisub/lua/modules.h>
@@ -270,6 +272,19 @@ namespace {
 		return 2;
 	}
 
+	int lua_set_status_text(lua_State *L)
+	{
+		const agi::Context *c = get_context(L);
+		if (!c || !c->frame) {
+			lua_pushnil(L);
+			return 1;
+		}
+		std::string text = check_string(L, 1);
+		lua_pop(L, 1);
+		agi::dispatch::Main().Async([=] { c->frame->StatusTimeout(to_wx(text)); });
+		return 0;
+	}
+
 	int project_properties(lua_State *L)
 	{
 		const agi::Context *c = get_context(L);
@@ -473,6 +488,7 @@ namespace {
 		set_field<get_translation>(L, "gettext");
 		set_field<project_properties>(L, "project_properties");
 		set_field<lua_get_audio_selection>(L, "get_audio_selection");
+		set_field<lua_set_status_text>(L, "set_status_text");
 
 		// store aegisub table to globals
 		lua_settable(L, LUA_GLOBALSINDEX);