New example: optimizeDataAccess.

Author: ReFreezed

RunExamples.cmd

@@ -6,6 +6,12 @@ ECHO Running %example%...
 lua main.lua %example%2p --debug --silent
 lua          %example%
 
+SET example=examples\optimizeDataAccess.lua
+ECHO.
+ECHO Running %example%...
+lua main.lua %example%2p --debug --silent
+lua          %example%
+
 SET example=examples\parseFile.lua
 ECHO.
 ECHO Running %example%...

examples/optimizeDataAccess.lua2p

@@ -0,0 +1,77 @@
+--[[============================================================
+--=
+--=  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")))