Config File Resource
The plConfigFileResource is used to load files which contain lists of variable value assignments ("key/value pairs"). These variables are strictly typed (int, float, bool or string) and it is very efficient to look up these values at runtime.
You can use this kind of configuration files for anything in your code. From general game settings, to defining the properties of different game elements.
Since all resources can be hot reloaded at runtime, using plConfigFileResources allows you to tweak values while playing to immediately see the effect.
An alternative to config file resources is custom data.
File Structure
The layout of config files is similar to C/C++ code, including the support for the C preprocessor.
Declaring Variables
To add a new variable, write its type, name and initial value:
Overriding Existing Variables
Once a variable has been declared the first time, it is an error to redeclare it the same way. Instead you need to add the override keyword:
It is also an error to declare a variable for the first time with the override keyword. This is to ensure that you have one place where the variable name is defined clearly, and to be able to point out where variables have been misspelled later on.
Defining Value Names
You can use #define to define a fixed name for a certain value:
This is more convenient to read and makes it easier to define and tweak values in one place.
Hierarchical File Structure
You can #include other config files to pull in their variable definitions:
Here the variable SomeValue must have been declared in BaseConfig.plConfig (or another file included by that file). The code then overrides the existing variable with a custom value. If BaseConfig.plConfig did not declare that variable, you will see an error in the log.
Using this feature, it is very convenient to define variables (and their default values) for things like units in a game (players, enemies, etc) and then override variables where needed for specific unit types.
Conditional Evaluation
You can use all C preprocessor features, such as #ifdef to conditionally evaluate the config files: