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Types

Spine type syntax describes either a named reference (possibly with type arguments) or a tuple of types.

Reference types​

[ '.' ] identifier ( '.' identifier )* [ '<' Type ( ',' Type )* '>' ]
  • Leading .: the name is absolute (resolved from the root namespace). Without it, the name is resolved using the current namespace and imports.
  • Generics: angle brackets supply type arguments, e.g. List<String>, JoinTrigger<String, Item>.

Qualified names use . between segments, e.g. com.dataspine.json.Value.

Tuple types​

'(' Type ( ',' Type )+ ','? ')'

Two or more types in parentheses form a tuple type. A single type in parentheses in an expression is grouping; in type positions, tuple types require at least two members.

Version suffixes on names​

An identifier may include @ and digits as part of the name (e.g. struct Foo@1, field prop@1: Type@2).

void​

void is allowed in type positions where the language defines it.

Standard library​

The Dataspine CLI loads the bundled standard library in the com.dataspine namespace (version 1) by default. You can attach more type definitions with --lib when running check or compile. See Runtime library.

Annotations on fields​

Struct fields may be prefixed with annotations:

Struct Foo {
    @AdminOnly(reference: something) secret: String,
}

Use @ followed by a type reference and optionally ( name: expr, ... ).