Replaced C++ implementation of the [objectives] tag by a Lua function.

data/core/_main.cfg

@@ -12,3 +12,7 @@
 {core/terrain-graphics/}
 {core/units.cfg}
 {core/editor/}
+
+[lua]
+	code=<< wesnoth.dofile("lua/wml-tags.lua") >>
+[/lua]

data/lua/wml-tags.lua

@@ -0,0 +1,76 @@
+local function all_teams()
+	local function f(s)
+		local i = s.i
+		local team = wesnoth.get_side(i)
+		s.i = i + 1
+		return team
+	end
+	return f, { i = 1 }
+end
+
+local function child_range(cfg, tag)
+	local function f(s)
+		local c
+		repeat
+			local i = s.i
+			c = cfg[i]
+			if not c then return end
+			s.i = i + 1
+		until c[1] == tag
+		return c[2]
+	end
+	return f, { i = 1 }
+end
+
+local function wml_objectives(cfg)
+	local _ = wesnoth.textdomain("wesnoth")
+	local objectives = ""
+	local win_objectives = ""
+	local lose_objectives = ""
+
+	local win_string = cfg.victory_string
+	if not win_string then
+		win_string = _ "Victory:"
+	end
+	local lose_string = cfg.defeat_string
+	if not lose_string then
+		lose_string = _ "Defeat:"
+	end
+
+	for obj in child_range(cfg, "objective") do
+		local condition = obj.condition
+		if condition == "win" then
+			win_objectives = win_objectives .. "\n@" .. obj.description
+		elseif condition == "lose" then
+			lose_objectives = lose_objectives .. "\n#" .. obj.description
+		else
+			wesnoth.message "Unknown condition, ignoring."
+		end
+	end
+
+	local summary = cfg.summary
+	if summary then
+		objectives = "*" .. summary .. "\n"
+	end
+	if win_objectives ~= "" then
+		objectives = objectives .. "*" .. win_string .. "\n" .. win_objectives .. "\n"
+	end
+	if lose_objectives ~= "" then
+		objectives = objectives .. "*" .. lose_string .. "\n" .. lose_objectives .. "\n"
+	end
+
+	local silent = cfg.silent
+	local side = cfg.side or 0
+	if side == 0 then
+		for team in all_teams() do
+			team.objectives = objectives
+			if not silent then team.objectives_changed = true end
+		end
+	else
+		local team = wesnoth.get_side(side)
+		team.objectives = objectives
+		if not silent then team.objectives_changed = true end
+	end
+end
+
+wesnoth.register_wml_action("objectives", wml_objectives)