# `Statifier.Document.Invoke`
[🔗](https://github.com/riddler/statifier-ex/blob/v2.0.0/lib/statifier/document/invoke.ex#L1)

An `<invoke>` element: spec 6.4's instruction to create an instance of an
external service.

Every mutually exclusive attribute pairing 6.4.1 names is nonetheless
simultaneously representable here, on purpose, so
`Statifier.Validator.Checks.Invoke` can report the shape rather than
lowering refusing to build it - the same division of labour
`Statifier.Document.Donedata`, `Statifier.Document.Content`, and
`Statifier.Document.Param` already follow for their own mutually exclusive
pairs:

- `type` "Must not occur with the 'typeexpr' attribute."
- `src` "Must not occur with the 'srcexpr' attribute or the `<content>`
  element."
- `id` "Must not occur with the 'idlocation' attribute."
- `namelist` "Must not occur with the `<param>` element."

`namelist` is `[String.t()]` from a whitespace-split `namelist` attribute
(5.9.2's space-separated list of location expressions); `autoforward` is a
`boolean()` mapped from `"true"`/`"false"`, defaulting `false` per 6.4.1's
own stated default - an out-of-range value is
`Statifier.Validator.Checks.Enums`'s `{:invoke_bad_autoforward, raw}` to
report, the same "lowering maps to the default, the validator slices the
source" division every other enumerated attribute here follows.

`finalize` distinguishes an absent `<finalize>` child from an empty one,
which spec 6.5 requires: `nil` means the `<invoke>` has no `<finalize>` at
all, and `%Statifier.Document.Block{content: []}` means it has one with no
executable content inside. This is the same absent-versus-empty shape
`content`/`params` already carry for `<donedata>`, told apart structurally
rather than by a sentinel.

# `t`

```elixir
@type t() :: %Statifier.Document.Invoke{
  attribute_locations: Statifier.Document.attribute_locations(),
  autoforward: boolean(),
  content: Statifier.Document.Content.t() | nil,
  finalize: Statifier.Document.Block.t() | nil,
  id: String.t() | nil,
  idlocation: String.t() | nil,
  location: Statifier.Parser.Location.t(),
  namelist: [String.t()],
  params: [Statifier.Document.Param.t()],
  src: String.t() | nil,
  srcexpr: String.t() | nil,
  type: String.t() | nil,
  typeexpr: String.t() | nil
}
```

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