metayaml

Metayaml is a proposed meta-language intended to describe YAML documents, their schemas, and transformations using a YAML-oriented notation. It provides a layer above raw YAML that lets developers specify data structures, constraints, and reusable definitions in a single, machine-readable form. The goal is to standardize how YAML configurations are described and validated across projects, teams, and tooling.

In metayaml, schemas are defined with typed fields, nested mappings, array item rules, and references to reusable definitions. It supports constraints such as required fields, type checks, range limits, and pattern matching, as well as mechanisms for parameterization and composition that let users generate multiple schema variants from a single definition. The syntax is designed to be friendly to YAML tooling and to map to existing validation ecosystems.

Metayaml is not a replacement for YAML data; it is a specification language intended to be processed by validators, documentation generators, and code generators. When adopted, metayaml definitions can be translated into validators such as JSON Schema or OpenAPI components, or into code that validates YAML configurations, generates sample data, or produces human-readable documentation.

Example (conceptual):

type: map

properties:

name:

type: string

age:

type: integer

minimum: 0

required:

- name

This illustrates a metayaml-style schema for a simple Person object. Status: as of 2025, metayaml lacks a formal standard and remains primarily in experimental or community-driven discussions rather than official adoption. See also YAML, JSON Schema, and schema languages for YAML-based configurations.