Add support for scripted meta-templates.

gtk2_ardour/ardour_ui.cc

@@ -3612,7 +3612,12 @@ ARDOUR_UI::get_session_parameters (bool quit_on_cancel, bool should_be_new, stri
 			_session_is_new = true;
 		}
 
-		if (likely_new && template_name.empty()) {
+		if (!template_name.empty() && template_name.substr (0, 11) == "urn:ardour:") {
+
+			ret = build_session_from_dialog (session_dialog, session_path, session_name);
+			meta_session_setup (template_name.substr (11));
+
+		} else if (likely_new && template_name.empty()) {
 
 			ret = build_session_from_dialog (session_dialog, session_path, session_name);
 
@@ -3828,23 +3833,7 @@ ARDOUR_UI::load_session (const std::string& path, const std::string& snap_name,
 	if (!mix_template.empty ()) {
 		/* if mix_template is given, assume this is a new session */
 		string metascript = Glib::build_filename (mix_template, "template.lua");
-		if (Glib::file_test (metascript, Glib::FILE_TEST_EXISTS | Glib::FILE_TEST_IS_REGULAR)) {
-			LuaState lua;
-			lua_State* L = lua.getState();
-			lua.Print.connect (&LuaInstance::_lua_print);
-			LuaInstance::register_classes (L);
-			LuaBindings::set_session (L, _session);
-			luabridge::push <PublicEditor *> (L, &PublicEditor::instance());
-			lua_setglobal (L, "Editor");
-			lua.sandbox (true);
-			lua.do_file (metascript);
-			try {
-				luabridge::LuaRef fn = luabridge::getGlobal (L, "template_load");
-				if (fn.isFunction()) {
-					fn ();
-				}
-			} catch (luabridge::LuaException const& e) { }
-		}
+		meta_session_setup (metascript);
 	}
 
 
@@ -3938,6 +3927,34 @@ ARDOUR_UI::build_session (const std::string& path, const std::string& snap_name,
 	return 0;
 }
 
+void
+ARDOUR_UI::meta_session_setup (const std::string& script_path)
+{
+	if (!Glib::file_test (script_path, Glib::FILE_TEST_EXISTS | Glib::FILE_TEST_IS_REGULAR)) {
+		return;
+	}
+
+	LuaState lua;
+	lua.Print.connect (&LuaInstance::_lua_print);
+	lua.sandbox (true);
+
+	lua_State* L = lua.getState();
+	LuaInstance::register_classes (L);
+	LuaBindings::set_session (L, _session);
+	luabridge::push <PublicEditor *> (L, &PublicEditor::instance());
+	lua_setglobal (L, "Editor");
+
+	lua.do_command ("function ardour () end");
+	lua.do_file (script_path);
+
+	try {
+		luabridge::LuaRef fn = luabridge::getGlobal (L, "session_setup");
+		if (fn.isFunction()) {
+			fn ();
+		}
+	} catch (luabridge::LuaException const& e) { }
+}
+
 void
 ARDOUR_UI::launch_chat ()
 {

gtk2_ardour/ardour_ui.h

@@ -656,6 +656,8 @@ private:
 	void save_template ();
 	void manage_templates ();
 
+	void meta_session_setup (const std::string& script_path);
+
 	void edit_metadata ();
 	void import_metadata ();
 

gtk2_ardour/session_dialog.cc

@@ -48,6 +48,7 @@
 
 #include "ardour/audioengine.h"
 #include "ardour/filesystem_paths.h"
+#include "ardour/luascripting.h"
 #include "ardour/recent_sessions.h"
 #include "ardour/session.h"
 #include "ardour/session_state_utils.h"
@@ -516,6 +517,16 @@ SessionDialog::populate_session_templates ()
 
 		row[session_template_columns.name] = (*x).name;
 		row[session_template_columns.path] = (*x).path;
+		row[session_template_columns.desc] = (*x).description;
+	}
+
+	LuaScriptList& ms (LuaScripting::instance ().scripts (LuaScriptInfo::SessionSetup));
+	for (LuaScriptList::const_iterator s = ms.begin(); s != ms.end(); ++s) {
+		TreeModel::Row row;
+		row = *(template_model->append ());
+		row[session_template_columns.name] = "Meta: " + (*s)->name;
+		row[session_template_columns.path] = "urn:ardour:" + (*s)->path;
+		row[session_template_columns.desc] = "urn:ardour:" + (*s)->description;
 	}
 
 	if (!templates.empty()) {

gtk2_ardour/session_dialog.h

@@ -165,10 +165,12 @@ private:
 		SessionTemplateColumns () {
 			add (name);
 			add (path);
+			add (desc);
 		}
 
 		Gtk::TreeModelColumn<std::string> name;
 		Gtk::TreeModelColumn<std::string> path;
+		Gtk::TreeModelColumn<std::string> desc;
 	};
 
 	SessionTemplateColumns session_template_columns;

scripts/_template_example.lua

@@ -1,14 +1,27 @@
---
--- Session Template setup-hook
+ardour {
+	["type"]    = "SessionSetup",
+	name        = "Recording Session",
+	description = [[Add as many mono tracks to the new session as there are physical audio inputs and optionally record-arm them.]]
+}
+
+---- For use with templates: Session Template setup-hook
 --
 -- If a script named 'template.lua' exists in a session-template folder
--- the `template_load` function of the script is called after
+-- the `session_setup` function of the script is called after
 -- creating the session from the template.
 --
--- (e.g. ~/.config/ardour5/templates/Template-Name/template.lua
+-- (e.g. ~/.config/ardour5/templates/Template-Name/template.lua)
+--
+--
+---- For use as meta-session
+--
+-- Every Lua script in the script-folder of type "SessionSetup"
+-- is listed as implicit template in the new-session dialog.
+-- The scripts 'session_setup' function  is called once after
+-- creating a new, empty session.
 --
 
-function template_load ()
+function session_setup ()
 	local e = Session:engine()
 	-- from the engine's POV readable/capture ports are "outputs"
 	local _, t = e:get_backend_ports ("", ARDOUR.DataType("audio"), ARDOUR.PortFlags.IsOutput | ARDOUR.PortFlags.IsPhysical, C.StringVector())
@@ -17,7 +30,7 @@ function template_load ()
 
 	local dialog_options = {
 		{ type = "heading", title = "Customize Session: " .. Session:name () },
-		{ type = "number", key = "tracks", title = "Create Tracks",  min = 0, max = 128, step = 1, digits = 0, default = tracks },
+		{ type = "number", key = "tracks", title = "Create Tracks",  min = 1, max = 128, step = 1, digits = 0, default = tracks },
 		{ type = "checkbox", key = "recarm", default = false, title = "Record Arm Tracks" },
 	}