# `CEL.Function.Overload`
[🔗](https://github.com/hansihe/pb_ex/blob/v0.2.0/cel_ex/lib/cel/function.ex#L55)

One signature of a `CEL.Function`, and the code that evaluates it.

  * `:id` — a name for this overload, unique within the environment;
    checked expressions record which overload each call resolved to.
  * `:args` — the argument types, as `t:CEL.Type.t/0`; for a
    `:receiver` call the receiver comes first. `{:param, "T"}` is a type
    parameter: every occurrence must have the same type.
  * `:result` — the result type, which may use the same parameters.
  * `:eval` — `{Module, function}`, called as
    `Module.function(args, ...context)` with the evaluated arguments as a
    list of `t:CEL.Value.t/0`, and returning `{:ok, value}`,
    `{:error, reason}` or `{:unknown, reason}`. Without `:eval` the
    overload can be type-checked but not evaluated.
  * `:eval_context` — extra arguments appended after the argument list,
    in order: `:vars` for the variable bindings, keyed by string name,
    `:call` for `%{function: name, overload_id: id, expr_id: id}`, and
    `:types` for the environment's `t:CEL.TypeProvider.t/0`, to read
    message arguments with.
  * `:strict` — when `false`, the function is also called with error and
    unknown arguments, as `{:error, %CEL.Error{}}` and
    `{:unknown, %CEL.Unknown{}}`. Defaults to `true`.

Other fields are used by CEL's built-in functions and may change.

# `t`

```elixir
@type t() :: %CEL.Function.Overload{
  args: CEL.Function.args(),
  combine: CEL.Function.combine(),
  eval: CEL.Function.eval(),
  eval_context: [CEL.Function.eval_context()],
  id: String.t(),
  on_dyn: CEL.Function.on_dyn(),
  result: CEL.Function.result(),
  strict: boolean()
}
```

---

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