Added [elseif] support, Lua part. Also included sanity checks for missing [then] tags inside [if]

data/lua/wml-tags.lua

@@ -339,15 +339,45 @@ local function if_while_handler(max_iter, pass, fail, cfg)
 	end
 end
 
-local function if_handler(cfg)
-	if_while_handler(1, "then", "else", cfg)
-end
-
 local function while_handler(cfg)
 	if_while_handler(65536, "do", nil, cfg)
 end
 
-wml_actions["if"] = if_handler
+-- since if and while are Lua keywords, we can't create functions with such names
+-- instead, we store the following anonymous functions directly into
+-- the table, using the [] operator, rather than by using the point syntax
+
+wml_actions["if"] = function( cfg )
+	-- raise error if [then] is missing
+	if not helper.get_child( cfg, "then" ) then
+		helper.wml_error "[if] missing required [then] tag"
+	end
+
+	if wesnoth.eval_conditional( cfg ) then -- evalutate [if] tag
+		for then_child in helper.child_range ( cfg, "then" ) do
+			handle_event_commands( then_child )
+		end
+		return -- stop after executing [then] tags
+	else
+		for elseif_child in helper.child_range ( cfg, "elseif" ) do
+			-- there's no point in executing [elseif] without [then]
+			if not helper.get_child( elseif_child, "then" ) then
+				helper.wml_error "[elseif] missing required [then] tag"
+			end
+			if wesnoth.eval_conditional( elseif_child ) then -- we'll evalutate the [elseif] tags one by one
+				for then_tag in helper.child_range( elseif_child, "then" ) do
+					handle_event_commands( then_tag )
+				end
+				return -- stop on first matched condition
+			end
+		end
+		-- no matched condition, try the [else] tags
+		for else_child in helper.child_range ( cfg, "else" ) do
+			handle_event_commands( else_child )
+		end
+	end
+end
+
 wml_actions["while"] = while_handler
 
 function wml_actions.switch(cfg)