doc

nyan

WTF?

nyan is a strongly typed hierarchical key-value database with patch functionality and inheritance.

Design idea

openage requires a very complex data storage to represent the hierarchy of its objects. Research and technology affects numerous units, civilization bonuses, monk conversions and all that with the goal to be ultimatively moddable by the community:

Current data representation formats make this nearly impossible to accomplish. Readability problems or huge lexical overhead led us to design a language crafted for our needs.

Enter nyan, which is our approach to store data in a new way™.

Core Principles

• Human-readable language
• More or less compact (readability > memory)
• General-purpose data definition + database features
• Changing data with patches at runtime
• Moddability of defined data
• Portable
• Object-oriented
• Typesafe

Srsly?

Let's create a new unit with a mod: a japanese tentacle monster.

TentacleMonster(Unit):
    name = "Splortsch"
    hp = 2000

Creation<TownCenter>():
    creates += {TentacleMonster}

TentacleMod(Mod):
    name = "Add the allmighty tentacle monster to your holy army"
    patches = {Creation}

Things like Unit and Mod are provided by the game engine, TownCenter is provided by the base game data.

When the engine activates the mod, your town center can create the new unit.

Why nyan?

• nyan allows easy modding
  • Data packs ship configuration data and game content as .nyan files
  • Modpacks can change and extend existing information easily, by applying data "patches"
  • Patches are applied whenever the libnyan user decides when or where to do so
• nyan is typesafe
  • The type of a member is stored when declaring it
  • The only things nyan can do: Hierarchical data declaration and patches
  • No member type casts
  • Only allowed operators for a member type can be called
• nyan is invented here™
  • we can change the specification to our needs whenever we want

Specification

A full specification is provided here.

Integration into a Game Engine

• Some .nyan files are shipped with the game engine

  • They describe things the engine is capable of, basically the mod API
  • That way, the engine can be sure that things exist
  • The engine can access all nyan file contents with type safety
  • The data files of the game then extend and change the API nyan::Objects

• The nyan database provides a C++ API used by the game engine

  • Can parse .nyan files and add all information to the database
  • Provides hooks so the engine can react on internal changes

• Data does not contain any executable code but can specify function names and parameters. The game engine is responsible for calling those functions or redirecting to custom scripts