# `WardrikRest.Schema`

Fits an operation's arguments into a size budget, as the JSON Schema of its tool.

Objects are listed as deep as the budget allows, the same depth for every argument, whether
they're the spec's types or written in place. An object past that depth is left as an object
that names it: a type by its name, and one written in place by its path from the tool or the
type it's in. One inside itself is `"A FilterExpression, as above."`.

    %{"type" => "object", "description" => "A Campaign; ads__describe gives its fields."}

    %{"type" => "object",
      "description" => ~s(An object; stripe__describe gives its fields as "stripe__PostCharges/shipping".)}

Only arguments keep their descriptions; `describe/4` gives an object's.

# `types`

```elixir
@type types() :: %{required(String.t()) => map()}
```

JSON Schemas by name, which may refer to each other as `%{"$ref" => name}`.

# `describe`

```elixir
@spec describe(types(), %{required(String.t()) => map()}, String.t(), String.t()) ::
  {:ok, map()} | :error
```

Returns the object `name` names, with its fields' descriptions, and the objects inside it as
named objects. `name` is a type of `types`, or a path from one or from a tool of `tools`, the
JSON Schema of each tool's arguments by its name. `describe` names the tool that describes them.

# `fit`

```elixir
@spec fit(
  [WardrikRest.Parameter.t()],
  types(),
  pos_integer(),
  {String.t(), String.t()}
) ::
  {%{required(String.t()) => map()}, [String.t()]}
```

Returns the JSON Schema of each of `parameters`, by name, within `budget` bytes of JSON where it
can be, and the names of the objects it left out. `tool` is the tool's name, which paths start
from, and `describe` names the tool that describes them.

---

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