Mate Language

Mate Object Graph Language

The Mate Object Graph (OG) Language is a Domain-Specific Language (DSL) used to define the structure of object graphs and guide fuzzing of object graph instances.

Core Syntax

A grammar consists of one or more type declarations. Each declaration follows this pattern:

TypeName -> {
    fieldName1: FieldType,
    fieldName2: FieldType,
    ...
}.

Type Names

Types usually correspond to Pharo classes (e.g., Person, BlElement).

Field Types

Fields can be defined by simply naming the type:

age: Age

The language supports several primary types out of the box:

• SmallInteger: Integer numbers.
• Float: Floating-point numbers.
• Boolean: true or false.
• String: Text strings.
• Color: Color objects.
• Point: X/Y coordinate pairs.

Multi-type fields can be defined using the pipe | operator:

geometry: BlRectangleGeometry | BlEllipseGeometry | BlTriangleGeometry

For more control over field values, use a dictionary-like syntax { ... }.

To define a collection of objects, use square brackets []:

children: { type: [ BlElement ], sizeBetween: 0 and: 10 }

• type: [ Type ]: Specifies it's an array of the given type.
• size: N: Exact size of the array.
• sizeBetween: min and: max: Range of possible sizes.

For built-in types like SmallInteger, you can restrict the range:

level: { type: SmallInteger, between: 0 and: 99 }
experience: { type: SmallInteger, greaterThan: 0 }

Restrict a field to a specific set of symbolic values:

orientation: { oneOf: { #top . #right . #left . #bottom } }

Here an example:

Player -> {
    name: String,
    characterClass: Warrior | Rogue | Mage,
    level: { type: SmallInteger, between: 1 and: 100 },
    inventory: { type: [ Item ], sizeBetween: 0 and: 20 },
    isOnline: Boolean
}.

Item -> {
    name: String,
    rarity: { oneOf: { #common . #rare . #epic . #legendary } }
}.