Playground

A schema, a default and data

Three kinds of statement about one value, combined in a single operation. The default yields to the data; the type holds either way.

port:    *8080 | integer
host:    string
host:    "localhost"

A contradiction, located

Two statements that cannot both hold are not a warning and not a silent last-writer-wins. They are an error naming both sites.

port: integer
port: "high"

Layers, without a precedence table

The prod block states one fact of its own and inherits the rest. Nothing is overridden, so the order the two blocks are written in cannot change the answer.

defaults: {
  replicas: *2 | integer
  logLevel: *"info" | string
}

prod: $.defaults & {
  replicas: 6
}

Hold data to a schema

The gate verb. The schema is an ordinary document, so validation is unification with a verdict attached, and a finding that names the line in each file.

service: {
  name: "checkout"
  port: "8080"
}

with schema.aon:

service: {
  name: string
  port: integer
}

Ask why a value holds

Every conjunct that contributed to the value at a path, with the row and column that wrote it. This is what a merge tool cannot tell you.

defaults: {
  replicas: *2 | integer
}

prod: $.defaults & {
  replicas: 6
}

Split across two files

The include on the first line pulls the second pane in. Both documents are real files in an in-browser filesystem, so it resolves exactly as it would on disk.

@"./schema.aon"

host: "localhost"
port: 443

with schema.aon:

host: string
port: *8080 | integer

Pin what it means, not how it is written

The canon-hash is taken over the document's meaning. Reformat this, reorder the keys, change the comments: the pin does not move. Change a value and it does.

# an entirely cosmetic comment
service: {
  port:    8080,
  name:    "checkout",
}

What changed between two versions

The earlier version on the right, the current one on the left. The answer is a list of paths, not a text diff: a key that moved has not changed.

service: {
  name: "checkout"
  port: 8080
  region: "eu-west-1"
}

with schema.aon:

service: {
  port: 8080
  name: "checkout"
}

Find the entries that say nothing

The spread template states what every sibling has, and auth restates one of those facts, so the document means the same thing without it. The verb finds that by deleting and re-evaluating, not by matching text.

services: {
  &: { tier: "standard", replicas: *1 | integer }

  auth:    { tier: "standard", replicas: 3 }
  billing: { replicas: 1 }
}

Write the stanza for an agent

What an agent needs in order to read this definition rather than restate it: the pin, the shape, and the four commands that answer questions about it.

service: {
  name: string
  port: *8080 | integer
}