# `StatifierDatamodel.Schema`
[🔗](https://github.com/riddler/statifier_datamodel/blob/v0.7.1/lib/statifier_datamodel/schema.ex#L1)

Where the datamodel document's JSON Schema is, and what it says (ADR-0002).

The package ships one JSON Schema, `priv/schemas/datamodel-document.schema.json`,
written by hand against JSON Schema draft-07 from ADR-0001 and its
amendments. It describes the well-formed version-1 document: the three
scopes in order, an entry's four required keys, a declaration's `kind`,
the booleans that must be booleans. A host validates a document against it
with whatever draft-07 validator its own language has, before anything
indexes the document.

## Advisory, never admission

Nothing in this package calls either function here, and nothing validates
a document against the file. `StatifierDatamodel.Index.index/1` stays the
admission step and answers exactly what it answered before the file
existed: a document the schema rejects indexes as it always did. The
schema is deliberately stricter than `index/1`, and that gap is what a
host checks for - a dropped scope, a `sensitive?` spelled as a string, a
declaration whose `kind` is neither `record` nor `shape`, each of which
indexes without a word and loses what the host meant. A rejection is a fact for the host to
read and a severity for the host to assign, never a verdict this package
issues.

## The two readers

`path/0` answers where the file is inside the installed application, so a
host finds it without knowing the package's install layout. `json/0`
answers its contents, embedded at compile time so reading it touches no
disk at run time. `json/0` answers the JSON text, not a decoded map: the
package decodes no JSON anywhere, and a host decodes it with the decoder
it already has.

The file's `$id` is keyed on the document `version` it describes, not on
the package version. A document `version` bump ships a second file beside
this one; until then both functions answer version 1.

The `$id` is an identifier, not a location: no request fetches it, and
the URL it spells does not resolve. A host reads the file through
`path/0` or `json/0`, never through its `$id`.

# `json`

```elixir
@spec json() :: String.t()
```

The document's JSON Schema as JSON text, embedded at compile time.

The text, not a decoded map; decode it with the JSON decoder the host
already has.

## Examples

    iex> StatifierDatamodel.Schema.json() =~ ~s("$schema": "http://json-schema.org/draft-07/schema#")
    true

# `path`

```elixir
@spec path() :: String.t()
```

The absolute path of the document's JSON Schema in the installed
application's `priv` directory.

## Examples

    iex> StatifierDatamodel.Schema.path() |> Path.basename()
    "datamodel-document.schema.json"

---

*Consult [api-reference.md](api-reference.md) for complete listing*