Lua API: Add inline documentation for pretty much everything

data/lua/core/_initial.lua

@@ -7,24 +7,34 @@ print("Loading Lua core files...")
 local _ = wesnoth.textdomain "wesnoth"
 
 -- Marks a function or subtable as deprecated.
--- Parameters:
----- elem_name: the full name of the element being deprecated (including the module)
----- replacement: the name of the element that will replace it (including the module)
----- level: deprecation level (1-4)
----- version: the version at which the element may be removed (level 2 or 3 only)
----- Set to nil if deprecation level is 1 or 4
----- elem: The actual element being deprecated, ignored if level is 4
----- detail_msg: An optional message to add to the deprecation message
-function wesnoth.deprecate_api(elem_name, replacement, level, version, elem, detail_msg)
+---@generic T
+---@param elem_name string the full name of the element being deprecated (including the module), to be shown in the deprecation message
+---@param replacement_name string the name of the element that will replace it (including the module), to be shown in the deprecation message
+--- Can be nil if there is not replacement, though this should be an unlikely situation
+---@param level '1'|'2'|'3'|'4' deprecation level (1-4)
+---@param version string|nil the version at which the element may be removed (level 2 or 3 only)
+--- Set to nil if deprecation level is 1 or 4
+--- Will be shown in the deprecation message
+---@param elem T Implementation of the compatibility layer, ignored if level is 4.
+--- This can be the original, pre-deprecated element, but it does not have to be.
+--- It could also be a wrapper that presents a different API, for example.
+--- If deprecating a function, that would mean a wrapper function that calls the new API.
+--- If deprecating a table, you would need to provide a table with __index and __newindex metamethods that call the new API.
+--- This is the only argument that affects the functionality of the resulting deprecation wrapper.
+---@param detail_msg? string An optional message to add to the deprecation message
+---@return T elem_deprecated #A wrapper around the element, which triggers a deprecation message when used.
+--- If it is a function, the message is triggered the first time it is called.
+--- If it is a table, the message is triggered when a key is written or read on the table.
+function wesnoth.deprecate_api(elem_name, replacement_name, level, version, elem, detail_msg)
 	if wesnoth.game_config.strict_lua then return nil end
 	local message = detail_msg or ''
-	if replacement then
-		message = message .. " " .. (_"(Note: You should use $replacement instead in new code)"):vformat{replacement = replacement}
+	if replacement_name then
+		message = message .. " " .. (_"(Note: You should use $replacement instead in new code)"):vformat{replacement = replacement_name}
 	end
 	if type(level) ~= "number" or level < 1 or level > 4 then
 		local err_params = {level = level}
 		-- Note: This message is duplicated in src/deprecation.cpp
-		-- Any changes should be mirrorred there.
+		-- Any changes should be mirrored there.
 		error((_"Invalid deprecation level $level (should be 1-4)"):vformat(err_params))
 	end
 	local msg_shown = false
@@ -55,7 +65,7 @@ function wesnoth.deprecate_api(elem_name, replacement, level, version, elem, det
 		if type(old_mt) ~= "table" then
 			-- See https://github.com/wesnoth/wesnoth/issues/4584#issuecomment-555788446
 			wesnoth.log('warn', "Attempted to deprecate a table with a masked metatable: " ..
-				elem_name .. " -> " .. replacement .. ", where getmetatable(" .. elem_name .. ") = " .. tostring(old_mt))
+				elem_name .. " -> " .. replacement_name .. ", where getmetatable(" .. elem_name .. ") = " .. tostring(old_mt))
 			return elem
 		end
 		local mt = {}
@@ -79,7 +89,7 @@ function wesnoth.deprecate_api(elem_name, replacement, level, version, elem, det
 		return setmetatable({}, mt)
 	else
 		wesnoth.log('warn', "Attempted to deprecate something that is not a table or function: " ..
-			elem_name .. " -> " .. replacement .. ", where " .. elem_name .. " = " .. tostring(elem))
+			elem_name .. " -> " .. replacement_name .. ", which is " .. tostring(elem))
 	end
 	return elem
 end

data/lua/core/as_text.lua

@@ -51,6 +51,8 @@ local function value_to_text(obj)
 	end
 end
 
+---Convert an arbitrary value (especially a table) to a string for debugging
+---@return string
 function wesnoth.as_text(...)
 	local result = {}
 	local n = 1

data/lua/core/filesystem.lua

@@ -2,6 +2,7 @@
 --[========[File Handling]========]
 print("Loading filesystem module...")
 
+---Valid asset types, used as the type argument for have_asset and resolve_asset
 filesystem.asset_type = {
     IMAGE = 'images',
     SOUND = 'sounds',

data/lua/core/gui.lua

@@ -2,6 +2,9 @@
 --[========[GUI2 Dialog Manipulations]========]
 print("Loading GUI module...")
 
+---Show a basic alert dialog with a single button
+---@param title string Dialog title string
+---@param msg string Detail message
 function gui.alert(title, msg)
 	if not msg then
 		msg = title;
@@ -10,6 +13,10 @@ function gui.alert(title, msg)
 	gui.show_prompt(title, msg, "ok", true)
 end
 
+---Show a basic prompt dialog with two buttons
+---@param title string Dialog title string
+---@param msg string Detail message
+---@return boolean #True if OK or Yes was clicked
 function gui.confirm(title, msg)
 	if not msg then
 		msg = title;
@@ -18,13 +25,10 @@ function gui.confirm(title, msg)
 	return gui.show_prompt(title, msg, "yes_no", true)
 end
 
---! Displays a WML message box with attributes from table @attr and options
---! from table @options.
---! @return the index of the selected option.
---! @code
---! local result = gui.get_user_choice({ speaker = "narrator" },
---!     { "Choice 1", "Choice 2" })
---! @endcode
+---Displays a WML message box with attributes from attr and options from options.
+---@param attr WML The contents of a [message] tag, without any [option]s.
+---@param options string[]|gui_narration_option_info[] A list of options to show in the message box
+---@return integer #the index of the selected option.
 function gui.get_user_choice(attr, options)
 	local result = 0
 	function gui.__user_choice_helper(i)

data/lua/core/interface.lua

@@ -5,8 +5,11 @@ if wesnoth.kernel_type() == "Game Lua Kernel" then
 
 	wesnoth.interface.select_unit = wesnoth.units.select
 
-	--! Fakes the move of a unit satisfying the given @a filter to position @a x, @a y.
-	--! @note Usable only during WML actions.
+	---Fakes the move of a unit satisfying the given filter to position x, y.
+	---Usable only during WML actions.
+	---@param filter WML
+	---@param to_x integer
+	---@param to_y integer
 	function wesnoth.interface.move_unit_fake(filter, to_x, to_y)
 		local moving_unit = wesnoth.units.find_on_map(filter)[1]
 		local from_x, from_y = moving_unit.x, moving_unit.y

data/lua/core/map.lua

@@ -1,10 +1,21 @@
 --[========[Map module]========]
 print("Loading map module...")
 
+---Splits a terrain code into base and overlay
+---@param code string
+---@return string #The base terrain, if any - an empty string if there's no base
+---@return string|nil #The overlay, if any - nil if there's no overlay
 function wesnoth.map.split_terrain_code(code)
 	return table.unpack(code:split('^', {remove_empty = false}))
 end
 
+---Read a location from the front of a variable argument list.
+---@alias read_location_count
+---| '0' #Indicates no location was found.
+---| '1' #A location-like object was found - either an array of two integers, or a table or userdata with x and y keys.
+---| '2' #Two integer arguments were found and interpreted as the x and y coordinates respectively.
+---@return location|nil #The location, if one was found, or nil otherwise
+---@return read_location_count count #The number of arguments used to extract the location.
 function wesnoth.map.read_location(...)
 	local x, y = ...
 	if x == nil then return nil, 0 end
@@ -28,6 +39,11 @@ if wesnoth.kernel_type() ~= "Application Lua Kernel" then
 	-- A        A^       A^B      ^        ^B
 	-- implied mode:
 	-- both     base     both     overlay  overlay
+
+	---Adjusts a terrain code to produce one that will replace the base terrain only,
+	---when the adjusted code is assigned to a terrain hex on the map
+	---@param code string A terrain code
+	---@return string #The adjusted terrain code
 	function wesnoth.map.replace_base(code)
 		local base, overlay = wesnoth.map.split_terrain_code(code)
 		if base == nil then -- ^ or ^B
@@ -39,6 +55,10 @@ if wesnoth.kernel_type() ~= "Application Lua Kernel" then
 		end
 	end
 
+	---Adjusts a terrain code to produce one that will replace the overlay terrain only,
+	---when the adjusted code is assigned to a terrain hex on the map
+	---@param code string A terrain code
+	---@return string #The adjusted terrain code
 	function wesnoth.map.replace_overlay(code)
 		local base, overlay = wesnoth.map.split_terrain_code(code)
 		if overlay == nil or overlay == '' then -- A or A^
@@ -50,6 +70,10 @@ if wesnoth.kernel_type() ~= "Application Lua Kernel" then
 		end
 	end
 
+	---Adjusts a terrain code to produce one that will replace both the base and overlay terrains,
+	---when the adjusted code is assigned to a terrain hex on the map
+	---@param code string A terrain code
+	---@return string #The adjusted terrain code
 	function wesnoth.map.replace_both(code)
 		local base, overlay = wesnoth.map.split_terrain_code(code)
 		if base == '' then -- ^ or ^B
@@ -66,6 +90,11 @@ if wesnoth.kernel_type() ~= "Application Lua Kernel" then
 		end
 	end
 
+	---Iterate over on-map hexes adjacent to a given hex.
+	---@param map terrain_map
+	---@return fun()
+	---@overload fun(map:terrain_map, loc:location)
+	---@overload fun(map:terrain_map, x:integer, y:integer)
 	function wesnoth.map.iter_adjacent(map, ...)
 		local where, n = wesnoth.map.read_location(...)
 		if n == 0 then error('wesnoth.map.iter_adjacent: missing location') end
@@ -86,6 +115,22 @@ if wesnoth.kernel_type() ~= "Application Lua Kernel" then
 end
 
 if wesnoth.kernel_type() == "Game Lua Kernel" then
+	---Represents a reference to a single hex on the map
+	---@class terrain_hex
+	---@field x integer
+	---@field y integer
+	---@field fogged boolean Whether the hex is fogged
+	---@field shrouded boolean Whether the hex is shrouded
+	---@field team_label? string|tstring The label on this hex visible to the current team
+	---@field global_label? string|tstring The label on this hex visible to teams who don't have a team label there
+	---@field label? string|tstring The visible label on this hex
+	---@field terrain string The terrain code of the hex
+	---@field base_terrain string The terrain code without the overlay
+	---@field overlay_terrain string The overlay terrain code without the base
+	---@field info terrain_info The properties of this terrain
+	---@field time_of_day time_info The base time of day on this hex from the schedule
+	---@field illuminated_time time_info The time of day on this hex, adjusted for illumination effects
+	local hex_methods = {}
 	local hex_mt = {__metatable = 'terrain hex reference'}
 
 	function hex_mt.__index(self, key)
@@ -120,7 +165,7 @@ if wesnoth.kernel_type() == "Game Lua Kernel" then
 		elseif key == 2 then
 			return self.y
 		elseif type(key) ~= string or (#key > 0 and key[0] ~= '_') then
-			return hex_mt[key]
+			return hex_methods[key]
 		end
 	end
 
@@ -167,48 +212,75 @@ if wesnoth.kernel_type() == "Game Lua Kernel" then
 		end
 	end
 
-	function hex_mt:fogged_for(side)
+	---Test if the hex is under fog for a specific side
+	---@param side integer|side
+	---@return boolean
+	function hex_methods:fogged_for(side)
 		return wesnoth.sides.is_fogged(side, self)
 	end
 
-	function hex_mt:shrouded_for(side)
+	---Test if the hex is under shroud for a specific side
+	---@param side integer|side
+	---@return boolean
+	function hex_methods:shrouded_for(side)
 		return wesnoth.sides.is_shrouded(side, self)
 	end
 
-	function hex_mt:set_shrouded(side, val)
+	---Set whether the hex is shrouded for a specific side
+	---@param side integer|side
+	---@param val boolean
+	function hex_methods:set_shrouded(side, val)
 		if val then
 			wesnoth.sides.place_shroud(side, {self})
 		else
 			wesnoth.sides.remove_shroud(side, {self})
 		end
 	end
 
-	function hex_mt:set_fogged(side, val)
+	---Set whether the hex is fogged for a specific side
+	---@param side integer|side
+	---@param val boolean
+	function hex_methods:set_fogged(side, val)
 		if val then
 			wesnoth.sides.place_fog(side, {self})
 		else
 			wesnoth.sides.remove_fog(side, {self})
 		end
 	end
 
-	function hex_mt:label_for(who)
+	---Get a label placed by a specific side
+	---@param who integer
+	---@return label_info
+	function hex_methods:label_for(who)
 		return wesnoth.map.get_label(self.x, self.y, who)
 	end
 
-	function hex_mt:matches(filter)
+	---Test if the hex matches a filter
+	---@param filter WML
+	---@return boolean
+	function hex_methods:matches(filter)
 		return wesnoth.map.matches(self.x, self.y, filter)
 	end
 
 	-- Backwards compatibility - length is always 2
 	hex_mt.__len = wesnoth.deprecate_api('#location', 'nil', 3, '1.17', function() return 2 end, 'Using the length of a location as a validity test is no longer supported. You should represent an invalid location by nil instead.')
 
+	---Get a hex reference to alias specific location
+	---@param x integer
+	---@param y integer
+	---@return terrain_hex
+	---@overload fun(loc:location):terrain_hex
 	function wesnoth.map.get(x, y)
 		local loc, n = wesnoth.map.read_location(x, y)
 		if n == 0 then error('Missing or invalid coordinate') end
 		return setmetatable(loc, hex_mt)
 	end
 
 	local find_locations = wesnoth.map.find
+	---Find a list of locations matching a filter
+	---@param cfg WML
+	---@param ref_unit? unit
+	---@return terrain_hex[]
 	function wesnoth.map.find(cfg, ref_unit)
 		local hexes = find_locations(cfg, ref_unit)
 		for i = 1, #hexes do
@@ -272,36 +344,73 @@ end
 
 if wesnoth.kernel_type() == "Mapgen Lua Kernel" then
 	wesnoth.map.filter_tags = {
+		---Match specific terrains
+		---@param terrain string
+		---@return terrain_filter_tag
 		terrain = function(terrain)
 			return { "terrain", terrain }
 		end,
+		---Match all the nested filters
+		---@vararg terrain_filter_tag
+		---@return terrain_filter_tag
 		all =  function(...)
 			return { "all", ... }
 		end,
+		---Match at least one of the nested filters
+		---@vararg terrain_filter_tag
 		any =  function(...)
 			return { "any", ... }
 		end,
+		---Match none of the nested filters
+		---@vararg terrain_filter_tag
+		---@return terrain_filter_tag
 		none =  function(...)
 			return { "none", ... }
 		end,
+		---Match not all of the nested filters
+		---@vararg terrain_filter_tag
+		---@return terrain_filter_tag
 		notall =  function(...)
 			return { "notall", ... }
 		end,
+		---Match adjacent hexes
+		---@param f terrain_filter
+		---@param adj direction[]
+		---@param count integer|string A range list
+		---@return terrain_filter_tag
 		adjacent =  function(f, adj, count)
 			return { "adjacent",  f, adjacent = adj, count = count }
 		end,
+		---Match hexes from a separate list.
+		---Specify the list in the second argument to wesnoth.map.filter()
+		---@param terrain string
+		---@return terrain_filter_tag
 		find_in =  function(terrain)
 			return { "find_in", terrain }
 		end,
+		---Match hexes within a given distance
+		---@param r integer
+		---@param f terrain_filter_tag
+		---@param f_r terrain_filter_tag
+		---@return terrain_filter_tag
 		radius =  function(r, f, f_r)
 			return { "radius", r, f, filter_radius = f_r}
 		end,
+		---Match hexes by x coordinate
+		---@param terrain integer|string A range list
+		---@return terrain_filter_tag
 		x =  function(terrain)
 			return { "x", terrain }
 		end,
+		---Match hexes by y coordinate
+		---@param terrain integer|string A range list
+		---@return terrain_filter_tag
 		y =  function(terrain)
 			return { "y", terrain }
 		end,
+		---Match a specific location
+		---@param loc location
+		---@return terrain_filter_tag
 		is_loc = function(loc)
 			return f.all(f.x(loc[1]), f.y(loc[2]))
 		end