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10 Type System

10.1 Core Types

DATEX defines a range of core types, from simple primitive types such as integer and text, to more complex composite types such as Map and Set.

The term "core value" refers to a concrete instance of a core type, while "value" is used in a broader sense to denote an instance of any type.

There is no difference between primitive and composite types in their usage. Both can be accessed as references and values.

10.1.1 List of Core Types

10.1.1.1 Non-instantiable Types

Type Description
unit The unit type has a single value, also called unit. It is used as the return type of a function that does not return anything.
never The never type has no values. It is used to indicate that a function does not return normally (e.g., it always throws an error).
unknown The unknown type is the supertype of all types. It can hold any value, but values of this type cannot be used directly.

10.1.1.2 Primitive Types

Type Variant Example (DATEX Syntax) Description
boolean true / false A boolean value can either be true or false.
null null A null value.
integer 42 An integer that can hold arbitrarily large finite positive and negative integer values.
u8 42u8 An integer with a range of 0 to 255.
u16 42u16 An integer with a range of 0 to 65,535.
u32 42u32 An integer with a range of 0 to 4,294,967,295.
u64 42u64 An integer with a range of 0 to 18,446,744,073,709,551,615.
ubig 42ubig An integer with an arbitrary large positive value.
i8 42i8 An integer with a range of -128 to 127.
i16 42i16 An integer with a range of -32,768 to 32,767.
i32 42i32 An integer with a range of -2,147,483,648 to 2,147,483,647.
i64 42i64 An integer with a range of -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807.
ibig 42ibig An integer with an arbitrary large negative or positive value.
decimal 42.0 A decimal that can hold arbitrarily large finite positive and negative decimal values with arbitrary precision. Additionally, it can hold the special values `infinity`, `-infinity ` and `nan`.
f32 42.0f32 A 32-bit floating point number.
f64 42.0f64 A 64-bit floating point number.
big 42.0big A decimal number with arbitrary precision.
amount 42m A value consisting of an arbitrary size and precision decimal number and a (composite) SI unit or currency unit
url https://unyt.org/ A URL.
endpoint @example A DATEX endpoint identifier.
anonymous @@123456789 An anonymous DATEX endpoint identifier.
person @user A DATEX endpoint identifier representing a person.
organisation @+unyt A DATEX endpoint identifier representing an organisation.
text "Hello DATEX" A string of text.
plain - A string of the text with the mime type text/plain.
markdown - A string of the text with the mime type text/markdown.
html - A string of the text with the mime type text/html.
... - TODO: additional text/* mime types
application - A binary blob with the mime type application/*.
json - A binary blob with the mime type application/json.
pdf - A binary blob with the mime type application/pdf.
... - TODO: additional application/* mime types
audio - An audio file with the mime type audio/*.
mp3 - An audio file with the mime type audio/mpeg.
wav - An audio file with the mime type audio/wav.
... - TODO: additional audio/* mime types
video - A video file with the mime type video/*.
mp4 - A video file with the mime type video/mp4.
webm - A video file with the mime type video/webm.
... - TODO: additional video/* mime types
image - An image file with the mime type image/*.
png - An image file with the mime type image/png.
jpeg - An image file with the mime type image/jpeg.
svg - An image file with the mime type image/svg+xml.
... - TODO: additional image/* mime types
font - A font file with the mime type font/*.
woff - A font file with the mime type font/woff.
woff2 - A font file with the mime type font/woff2.
... - TODO: additional font/* mime types
model - A 3D model file with the mime type model/*.
gltf - A 3D model file with the mime type model/gltf+json.
glb - A 3D model file with the mime type model/gltf-binary.
... - TODO: additional model/* mime types
10.1.1.2.1 Amounts

An amount consists of a decimal number and a unit. The unit can either be a SI unit or a currency unit.

SI Base Units
Unit Description Example DATEX Value DATEX Type
m meter 42m amount/m
kg kilogram 42kg amount/kg
s second 42s amount/s
A ampere 42A amount/A
K kelvin 42K amount/K
mol mole 42mol amount/mol
cd candela 42cd amount/cd
Currency Units
Unit Description Example DATEX Value DATEX Type
EUR Euro 42EUR amount/EUR
USD US Dollar 42USD amount/USD
GBP British Pound 42GBP amount/GBP
JPY Japanese Yen 42JPY amount/JPY
CHF Swiss Franc 42CHF amount/CHF
... ... ... ...

10.1.1.3 Composite Types

Type Example (DATEX Syntax) Description
List (1,2,3) A list of arbitrary values.
Array [1,2,3] An array of arbitrary values with a fixed length.
Map ("key": "value", (1): 2) A map of arbitrary key-value pairs.
Struct {name: "Alice", age: 30} A struct with fixed named fields containing arbitrary values.
Set Set(1,2,3) A set of unique arbitrary values.
Function function (x: integer) -> integer ( x * 2 ). A pure function that returns the same output value for the same input value, without side effects.
Procedure procedure (x: integer) -> integer ( x * 2 ) A procedure that can have side effects and does not guarantee the same output for the same input.
... ... ...

DATEX Script example (TODO move)

const a = 10; // inferred type for x is 'integer'
const b: integer/i8 = 255; // explicitly specifying type as signed 8-bit integer
const c: text/markdown = "# Markdown content";
const d = (1,2,3); // inferred type is List<integer>
const d: List<integer/i8> = (1,2,3); // Explicitly create a List containing only signed 8-bit integers
const s1 = Set (1,2,3); // creating a new value of type Set<integer> (inferred)
const s3 = Set<integer|text>(1,2,3); // creating a Set with an explicit type

Core types are available on every endpoint instance. Custom type definitions can be loaded as pointers from other endpoints.

10.2 Nominal and Structural Types

The DATEX type system provides both nominal and structural typing.

10.2.1 Type Aliases

10.3 Interfaces

Interfaces are special types that cannot be instantiated. They can contain overridable and sealed properties.

10.4 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.

10.5 The Function interface

The Function<I,O> interface implements the ValueConsumer<I,O> interface.

10.6 The SyncConsumer interface

10.7 The Instantiator interface

The Instantiator interface extends the ValueConsumer interface

10.8 The StreamConsumer interface