def.md

.def File Format

The .def file format will look familiar to C/C++ programmers, with minimal differences.

Includes

.def files can include other .def files using #include:

#include "../path/file.def"

Structs

You define a struct with the struct keyword, like you do in C++.

struct SomeStruct
{
    float a;
    int b;
};

Unions

Unions are declared similarly, but can only store one of the fields. Unions are a way of having a type which can be one of many other types. For instance, you could have a list of components on an object, where each component was a union of the different component types. That would let you have a list of different types of components on the object. Unions can also be "no object", so can be null.

union SomeUnion
{
    float a;
    int b;
};

Enums

Enums are integer values, but they have a human readable label to use instead of a "magic number".

enum Vegetables
{
    Carrot,
    Zucchini,
    Broccoli
};

Table Root Type

You must set the root type of a table using the #root keyword. The root type must be a struct.

#root SomeStruct

Comments

Both single line comments, and block comments are supported.

// This is my favorite struct
struct MyStruct
{
    float health;
    //float mana;
    int experience;

/*
    float armor;
    float attack;
    float flamability;
*/

    string favoriteSnack;
};

/* Here is an explanation
why this is my
favorite struct.
It just is.*/

Field Types

Fields can be various types:

• bool - true or false
• integers - uint8, int8, uint16, int16, uint32, int32, uint64, int64
• floats - float, double
• string - text
• enum - integers that have labels
• struct - a different struct
• union - a data type that allows a field to be one of a specific list of types. Can be null.
• link - a link to a table entry. Can be null.

default values can optionally be specified. If no default given, the field is zero initialized.

struct SomeStruct
{
    int a = 3;
    float b = 1.34f;
    int c; // zero initialized
    string s = "hello!";
};

Links

The only new one here is link. A link can point at entries from this table, or other tables. A link can also be none (null). A link is a templated object which takes the table root type as the parameter.

struct DoubleLink
{
    Link<SomeStruct> link1;
    Link<Monster> link2;
};

Arrays

Any struct field can be an array. Arrays can either be fixed size or dynamic size. A fixed size array gives the size in brackets, while a dynamic array does not give a size.

struct ArrayStruct
{
    // A float3 position
    float position[3];

    // An unbounded number of fears of specific monsters.
    Link<Monster> fears[];
};