ADR 08: Compound types are vector data

Date: 2026-06-16

Context

Compound boundary types (slices, pointers, arrays, optionals) need a representation.

Decision

Represent compound boundary types as vectors, such as [:slice :const :u8].

Consequences

Vector forms are plain data: easy to compose, validate, and build with Clojure-side helpers and macros.

Alternatives

Opaque type objects or constructor calls were considered; they block composition and make the public contract harder to read and manipulate (see ADR 15).