optimizeDataAccess.lua2p

--[[============================================================
--=
--=  LuaPreprocess example: Optimize data access.
--=
--=  Here we have all data defined in one single place in the
--=  metaprogram, then we export parts of the data into multiple
--=  smaller tables that are easy and fast to access in the
--=  final program.
--=
--============================================================]]

!(
local IS_DEVELOPER = false

local CHARACTERS = {
	{id="war1",  type="warrior", race="human",   name="Steve", unlockedByDefault=true,  devOnly=false},
	{id="war2",  type="warrior", race="orc",     name="Bog",   unlockedByDefault=false, devOnly=false},
	{id="mage1", type="mage",    race="human",   name="Elise", unlockedByDefault=true,  devOnly=false},
	{id="mage2", type="mage",    race="elf",     name="Cyan",  unlockedByDefault=false, devOnly=false},
	{id="arch1", type="archer",  race="elf",     name="Di",    unlockedByDefault=true,  devOnly=false},
	{id="arch2", type="archer",  race="monster", name="#&%€",  unlockedByDefault=false, devOnly=false},
	{id="dev",   type="dev",     race="human",   name="Dev",   unlockedByDefault=true,  devOnly=true},
}
)

-- Array of character IDs, excluding special characters if we're not in developer mode.
CHARACTER_IDS = {
	!for _, char in ipairs(CHARACTERS) do
		!if not char.devOnly or IS_DEVELOPER then
			!(char.id),
		!end
	!end
}

-- Maps between character IDs and other parameters.
CHARACTER_NAMES = {
	!for _, char in ipairs(CHARACTERS) do
		!!(char.id) = !(char.name),
	!end
}
CHARACTER_TYPES = {
	!for _, char in ipairs(CHARACTERS) do
		!!(char.id) = !(char.type),
	!end
}
CHARACTERS_UNLOCKED_BY_DEFAULT = {
	!for _, char in ipairs(CHARACTERS) do
		!if char.unlockedByDefault then
			!!(char.id) = true,
		!end
	!end
}

--
-- Instead of iterating over the CHARACTERS array until we find
-- the character with the specified ID, we use the maps above to
-- get the information we want through a single table lookup.
--
function getCharacterName(charId)
	return CHARACTER_NAMES[charId]
end
function getCharacterType(charId)
	return CHARACTER_TYPES[charId]
end
function isCharacterUnlockedByDefault(charId)
	return CHARACTERS_UNLOCKED_BY_DEFAULT[charId] == true
end

function printCharacterInfo()
	for _, charId in ipairs(CHARACTER_IDS) do
		print(getCharacterName(charId))
		print("  Type ...... "..getCharacterType(charId))
		print("  Unlocked .. "..tostring(isCharacterUnlockedByDefault(charId)))
	end
end

printCharacterInfo()
print("Type of 'war1': "..getCharacterType("war1"))
print("Is 'mage2' unlocked by default: "..tostring(isCharacterUnlockedByDefault("mage2")))