Every type in Raven's type engine is either one of five primitives, or something built out of them. This page covers the primitives themselves — the atoms everything else composes.

The five primitives

let name: string = "Ada"
let age: number = 37
let active: boolean = true
let anything: any = 42
let nothing: none = none

These are the only five identifiers the type checker treats specially. Any other identifier used where a type is expected — Node, User, whatever you've named a model — is treated as a type reference, not a primitive. See Recursive Types for how those resolve.

Type inference

Annotations are optional on let and const. Leave one off, and Raven infers the type from the value:

let name = "Ada"       // inferred as string
const pi = 3.14        // inferred as number

If you do write an annotation, Raven checks the value against it and reports a mismatch if they don't line up:

let age: number = "oops"
// Type mismatch in declaration of 'age': expected 'number', but got '"oops"'

any disables checking, deliberately

any is the escape hatch. Assigning any into a typed slot, or a typed value into an any slot, always succeeds — the type checker treats any as compatible with everything in both directions. Reach for it when a shape genuinely can't be known yet (Raven itself uses it internally for external data sources — see Recursive Types for how model database.users works).

none is a real type, not just "no value"

none behaves like any other primitive — it can be compared, stored, and checked. What makes it useful is combining it with other types via ?, covered in Optional Types.

What's next

Primitives are also the foundation every literal type narrows from — "admin" is a more specific version of string, 200 a more specific version of number. That relationship, and exactly which direction it's allowed to flow, is covered in Literal Types.