add wml_actions.make_tag as proposed at #1503

data/lua/wml/make_tag.lua

@@ -0,0 +1,52 @@
+local helper = wesnoth.require("lua/helper.lua")
+local T = helper.set_wml_tag_metatable {}
+
+-- a map string -> vconfig
+local wml_defined_tags = {}
+
+local add_new_wml_tag = function(tagname, command)
+	if type(command) == "table" then
+		command = wesnoth.tovconfig(command)
+	end
+	wml_defined_tags[tagname] = command
+	wesnoth.wml_actions[tagname] = function(args)
+		local old_args = wesnoth.get_variable("a")
+		wesnoth.set_variable("a", args)
+		wesnoth.wml_actions.command(command)
+		wesnoth.set_variable("a", old_args)
+	end
+
+end
+
+local old_on_save = wesnoth.game_events.on_save
+wesnoth.game_events.on_save = function()
+	local cfg = old_on_save()
+	for k,v in pairs(wml_defined_tags) do
+		table.insert(cfg, T.wml_defined_tag {
+			tagname = k,
+			T.command(helper.literal(v)),
+		})
+	end
+	return cfg
+end
+
+local old_on_load = wesnoth.game_events.on_load
+wesnoth.game_events.on_load = function(cfg)
+	for i = #cfg,1,-1 do
+		local v = cfg[i]
+		if v[1] == "wml_defined_tag" then
+			local v2 = v[2]
+			add_new_wml_tag(v2.tagname, helper.get_child(v2, "command") )
+			table.remove(cfg, i)
+		end
+	end
+	old_on_load(cfg)
+end
+
+wesnoth.wml_actions.make_tag = function(cfg)
+	local tagname = cfg.tagname or helper.wml_error "[make_tag] missing required tagname= attribute."
+	local command = helper.get_child(cfg, "command") or helper.wml_error "[make_tag] missing required command= child."
+	add_new_wml_tag(tagname, command)
+end
+
+