lua script to bounce regions w/processing and replace the region

scripts/bounce_replace.lua

@@ -0,0 +1,66 @@
+ardour { ["type"] = "EditorAction", name = "Bounce+Replace Regions",
+	license     = "MIT",
+	author      = "Robin Gareus",
+	email       = "robin@gareus.org",
+	site        = "http://gareus.org",
+	description = [[Bounce selected regions with processing and replace region]]
+}
+
+function factory (params) return function ()
+	-- there is currently no direct way to find the track
+	-- corresponding to a [selected] region
+	function find_track_for_region (region_id)
+		for route in Session:get_tracks():iter() do
+			local track = route:to_track();
+			local pl = track:playlist ()
+			if not pl:region_by_id (region_id):isnil () then
+				return track
+			end
+		end
+		assert (0); -- can't happen, region must be in a playlist
+	end
+
+	-- get selection
+	-- http://manual.ardour.org/lua-scripting/class_reference/#ArdourUI:Selection
+	local sel = Editor:get_selection ()
+
+	-- prepare undo operation
+	Session:begin_reversible_command ("Bounce+Replace Regions")
+	local add_undo = false -- keep track if something has changed
+
+	-- Iterate over Regions part of the selection
+	-- http://manual.ardour.org/lua-scripting/class_reference/#ArdourUI:RegionSelection
+	for r in sel.regions:regionlist ():iter () do
+		-- each of the items 'r' is a
+		-- http://manual.ardour.org/lua-scripting/class_reference/#ARDOUR:Region
+
+		local track = find_track_for_region (r:to_stateful():id())
+		local playlist = track:playlist ()
+
+		-- clear existing changes, prepare "diff" of state for undo
+		playlist:to_stateful ():clear_changes ()
+
+		-- bounce the region with processing
+		local region = track:bounce_range (r:position (), r:position() + r:length (), ARDOUR.InterThreadInfo (), track:main_outs (), false);
+
+		-- remove old region..
+		playlist:remove_region (r);
+		-- ..and add the newly bounced one
+		playlist:add_region (region, r:position (), 1, false)
+
+		-- create a diff of the performed work, add it to the session's undo stack
+		-- and check if it is not empty
+		if not Session:add_stateful_diff_command (playlist:to_statefuldestructible ()):empty () then
+			add_undo = true
+		end
+	end
+
+	-- all done, commit the combined Undo Operation
+	if add_undo then
+		-- the 'nil' Command here mean to use the collected diffs added above
+		Session:commit_reversible_command (nil)
+	else
+		Session:abort_reversible_command ()
+	end
+
+end end