10 Data Types and Values
DATEX has a variety of standard data types, including primitives, JSON data types, Records, Maps and Sets. Functionally, there is no difference between primitive and non-primitive types - both can be accessed by reference or value and can be used as a base for custom types.
DATEX Script example:
val a = 10; // inferred type for x is 'integer'
val b: integer/8 = 255; // explicitly specifying type as signed 8-bit integer
val c: text/markdown = "# Markdown content";
val d = (1,2,3); // inferred type is (integer, integer, integer)
val d:Array<integer/8> = [1,2,3]; // Explicitly create an array containing only signed 8-bit integers
val s1 = Set (1,2,3); // creating a new value of type Set<integer> (inferred)
val s3 = Set<any>(1,2,3); // creating a Set with an explicit type
val s2: Set<integer> = xy() // type checking (TODO when infer?)The standard data types are available on every endpoint instance. Custom type definitions can be loaded as pointers from other endpoints.
10.1 Nominal and Structural Types
The DATEX type system is fundamentally a nominal type system. Values are always associated with a nominal type.
Structural type matching is used for primitive values, JSON values and Records.
10.1.1 Type Aliases
10.2 Interfaces
Interfaces are special types that cannot be instantiated. They can contain overridable and sealed properties.
10.3 The ValueConsumer interface
The ValueConsumer<I,O> interface has a single property called handleValue. This property has to be assigned to a Function<I,O>. The function takes a value of type I as input and returns a value of type O.
10.4 The Function interface
The Function<I,O> interface implements the ValueConsumer<I,O> interface.
10.5 The SyncConsumer interface
10.6 The Instantiator interface
The Instantiator interface extends the ValueConsumer interface
10.7 The StreamConsumer interface
10.8 Any
Disjunction of all values/types
10.9 Primitive Types
10.9.1 The boolean type
A boolean value can either be true or false.
10.9.2 The integer type
10.9.3 The text type
10.9.4 The null type
const value+type
10.9.5 The integer type
10.9.6 The decimal type
10.9.7 The quantity type
10.9.8 The buffer type
10.9.9 The time type
10.9.10 The color type
10.9.11 The endpoint type
10.9.12 The symbol type
10.9.13 The image type
10.9.14 The audio type
10.9.15 The video type
10.9.16 The model type
10.9.17 The font type
10.9.18 The application type
10.10 Records
Records are non-extendable key-value data structures. All properties must be specified on creation. New properties cannot be added. Records can contain integer and text keys.
Example:
val record = (1, 2, 3, a:'text', b:42)Per default, any value can be assigned to a key. The allowed types for keys of a Record<T> can be specified with the generic parameter T:
Record<text> // allow only text values for any key
Record<(a:text, b:integer)> // allow only a property 'a' with type text and a property 'b' with type integer10.11 Objects
Objects are extendable key-value data structures. Only text keys are allowed. New properties can be added and existing properties can be deleted after creation. Per default, any value can be assigned to a key.
10.12 Arrays
Arrays are extendable key-value data structures. Only integer keys are allowed. New properties can be added and existing properties can be deleted after creation. Per default, any value can be assigned to a key.