Expose the Aegisub version to Lua as aegisub.version

automation/v4-docs/misc.txt

@@ -31,6 +31,39 @@ Returns: 4 values, all numbers.
 
 ---
 
+Getting the Aegisub version
+
+aegisub.version (table)
+
+A table describing the version of Aegisub the script is running in, with
+these fields:
+
+@string (string)
+  The full version string, e.g. "3.5.0" for a release or
+  "9900-master-4e440a614" for a development build. Use it for display and
+  logging only; its format may change.
+
+@major, @minor, @patch (numbers)
+  The version numbers of the latest release this version of Aegisub was built
+  from (or of the release being prepared). A development build made after
+  3.5.0 reports 3.5.0, so it is safe to use these to check that the features
+  of a given release are available.
+
+@build (number or nil)
+  The build number, which increases with every commit to Aegisub's main
+  branch. It can be used to check for features which were added after the
+  latest release, but is only meaningful for official builds: other branches
+  and forks may number their builds differently. nil if unknown.
+
+Wherever possible, check for the specific feature you need instead, e.g.
+"if aegisub.some_function then". The version is mainly useful for changes that
+can't be detected that way, such as new optional arguments.
+
+aegisub.version was added after 3.5.0; scripts that need to run in older
+versions should check that it exists first.
+
+---
+
 Getting the audio waveform selection position and duration
 
 function aegisub.get_audio_selection()

meson.build

@@ -96,6 +96,13 @@ if get_option('debug') and host_machine.system() != 'windows'
 endif
 
 conf = configuration_data()
+# The version declared above is that of the latest release this was built
+# from, or of the release being prepared
+aegisub_version = meson.project_version().split('.')
+assert(aegisub_version.length() == 3, 'The project version must be of the form X.Y.Z')
+conf.set('AEGISUB_VERSION_MAJOR', aegisub_version[0].to_int())
+conf.set('AEGISUB_VERSION_MINOR', aegisub_version[1].to_int())
+conf.set('AEGISUB_VERSION_PATCH', aegisub_version[2].to_int())
 conf.set_quoted('P_DATA', dataroot)
 conf.set_quoted('P_LOCALE', localedir)
 if get_option('credit') != ''

src/auto4_lua.cpp

@@ -53,6 +53,7 @@
 #include "subs_controller.h"
 #include "video_controller.h"
 #include "utils.h"
+#include "version.h"
 
 #include <libaegisub/dispatch.h>
 #include <libaegisub/lua/ffi.h>
@@ -115,6 +116,20 @@ namespace {
 		return 1;
 	}
 
+	/// Push the table for aegisub.version
+	void push_version(lua_State *L)
+	{
+		lua_createtable(L, 0, 5);
+		set_field(L, "string", GetVersionNumber());
+		auto numbers = GetVersionNumbers();
+		set_field(L, "major", numbers[0]);
+		set_field(L, "minor", numbers[1]);
+		set_field(L, "patch", numbers[2]);
+		// Unknown when built from a shallow clone
+		if (int build = GetSVNRevision())
+			set_field(L, "build", build);
+	}
+
 	int get_translation(lua_State *L)
 	{
 		wxString str(check_wxstring(L, 1));
@@ -504,7 +519,7 @@ namespace {
 
 		// make "aegisub" table
 		lua_pushstring(L, "aegisub");
-		lua_createtable(L, 0, 13);
+		lua_createtable(L, 0, 14);
 
 		set_field<LuaCommand::LuaRegister>(L, "register_macro");
 		set_field<LuaExportFilter::LuaRegister>(L, "register_filter");
@@ -516,6 +531,8 @@ namespace {
 		set_field<decode_path>(L, "decode_path");
 		set_field<cancel_script>(L, "cancel");
 		set_field(L, "lua_automation_version", 4);
+		push_version(L);
+		lua_setfield(L, -2, "version");
 		set_field<clipboard_init>(L, "__init_clipboard");
 		set_field<raise_warning_onload>(L, "__raise_warning");
 		set_field<get_file_name>(L, "file_name");

src/version.cpp

@@ -74,6 +74,10 @@ bool GetIsOfficialRelease() {
 #endif
 }
 
+std::array<int, 3> GetVersionNumbers() {
+	return {AEGISUB_VERSION_MAJOR, AEGISUB_VERSION_MINOR, AEGISUB_VERSION_PATCH};
+}
+
 const char *GetVersionNumber() {
 	return BUILD_GIT_VERSION_STRING;
 }

src/version.h

@@ -34,6 +34,8 @@
 
 #pragma once
 
+#include <array>
+
 /// Version string appended in title bar of main window (quick identification of all elements of a build)
 const char *GetAegisubLongVersionString();
 /// Version string used in About box, looks nicer
@@ -44,6 +46,9 @@ const char *GetAegisubBuildTime();
 const char *GetAegisubBuildCredit();
 /// Is release?
 bool GetIsOfficialRelease();
+/// The version numbers declared in meson.build: those of the latest release
+/// this was built from, or of the release being prepared
+std::array<int, 3> GetVersionNumbers();
 /// Version number
 const char *GetVersionNumber();
 /// Get SVN revision