defmodule Absinthe.Type.Enum do
@moduledoc """
Used to define an enum type, a special scalar that can only have a defined set
of values.
See the `t` type below for details and examples.
## Examples
Given a type defined as the following (see `Absinthe.Schema.Notation`):
```
@desc "The selected color channel"
enum :color_channel do
value :red, as: :r, description: "Color Red"
value :green, as: :g, description: "Color Green"
value :blue, as: :b, description: "Color Blue"
value :alpha, as: :a, deprecate: "We no longer support opacity settings", description: "Alpha Channel"
end
```
The "ColorChannel" type (referred inside Absinthe as `:color_channel`) is an
Enum type, with values with names "red", "green", "blue", and "alpha" that map
to internal, raw values `:r`, `:g`, `:b`, and `:a`. The alpha color channel
is deprecated, just as fields and arguments can be.
You can omit the raw `value` if you'd like it to be the same as the
identifier. For instance, in this example the `value` is automatically set to
`:red`:
```
enum :color_channel do
description "The selected color channel"
value :red, description: "Color Red"
value :green, description: "Color Green"
value :blue, description: "Color Blue"
value :alpha, deprecate: "We no longer support opacity settings", description: "Alpha Channel"
end
```
If you really want to use a shorthand, skipping support for descriptions,
custom raw values, and deprecation, you can just provide a list of atoms:
```
enum :color_channel, values: [:red, :green, :blue, :alpha]
```
Keep in mind that writing a terse definition that skips descriptions and
deprecations today may hamper tooling that relies on introspection tomorrow.
"""
use Absinthe.Introspection.TypeKind, :enum
alias Absinthe.{Blueprint, Type}
@typedoc """
A defined enum type.
Should be defined using `Absinthe.Schema.Notation.enum/2`.
* `:name` - The name of the enum type. Should be a TitleCased `binary`. Set automatically.
* `:description` - A nice description for introspection.
* `:values` - The enum values, usually provided using the `Absinthe.Schema.Notation.values/1` or `Absinthe.Schema.Notation.value/1` macro.
The `__private__` and `:__reference__` fields are for internal use.
"""
@type t :: %__MODULE__{
name: binary,
description: binary,
values: %{binary => Type.Enum.Value.t()},
identifier: atom,
__private__: Keyword.t(),
definition: module,
__reference__: Type.Reference.t()
}
defstruct name: nil,
description: nil,
identifier: nil,
values: %{},
values_by_internal_value: %{},
values_by_name: %{},
__private__: [],
definition: nil,
__reference__: nil
# Get the internal representation of an enum value
@doc false
@spec parse(t, any) :: any
def parse(enum, %Blueprint.Input.Enum{value: external_value}) do
Map.fetch(enum.values_by_name, external_value)
end
def parse(_, _) do
:error
end
# Get the external representation of an enum value
@doc false
@spec serialize(t, any) :: binary
def serialize(enum, internal_value) do
Map.fetch!(enum.values_by_internal_value, internal_value).name
end
end