Blue Language
The content language for typed nodes, schemas, overlays, references, deterministic resolution, and semantic content identity.
What it answers#
Blue Language answers: what is the content, what does it mean, and what is its exact identity?
It defines the node model, reserved fields, scalar/list/object payloads, types, item types, schemas, overlay and merge semantics, restricted portable YAML, references, resolution, canonical identity input, BlueId, minimization, and circular reference identity.
A type is a Blue node#
Types are not an external schema language. Any Blue node can serve as a type, which means types can carry fixed values, fields, constraints, nested types, contracts, and identity-bearing semantic descriptions.
This makes a type more than a shape. It can represent an exact semantic promise.
Source and resolved views#
An author writes a Source Document. Preprocessing expands declared aliases or transformations. Providers materialize required references. Type chains and overlays resolve into a validated semantic view. Canonicalization creates the input used for BlueId.
These views should remain explicit in an implementation. Editing a resolved view as if it were source can accidentally turn inherited content into local fixed meaning.
Portable YAML is restricted#
Blue uses the JSON data model even when YAML is the authoring syntax. Duplicate keys, custom tags, anchors, merge keys, non-string keys, implicit YAML timestamps, and other YAML-specific semantics are rejected for portability.
Security boundary#
A Node Provider may choose availability, but it does not get to redefine referenced content. Every returned node must verify against the requested BlueId.
Content identity must not be confused with authorship, freshness, authority, or provider truth.
Where to go next#
Use the concept page for a tutorial explanation. Use repo.blue for exact canonical types. Use the Blue specification repository for normative algorithms and fixtures. Use language libraries for parsing, resolution, identity, and provider integration APIs.