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lib/absinthe/type/enum.ex

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.Kind
alias Absinthe.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 `:__reference__` key is for internal use.
"""
@type t :: %{name: binary, description: binary, values: %{binary => Type.Enum.Value.t}, __reference__: Type.Reference.t}
defstruct name: nil, description: nil, values: %{}, values_by_internal_value: %{}, values_by_name: %{}, __reference__: nil
def build(%{attrs: attrs}) do
raw_values = attrs[:values] || []
values = Type.Enum.Value.build(raw_values)
internal_values = Type.Enum.Value.build(raw_values, :value)
values_by_name = Type.Enum.Value.build(raw_values, :name)
quote do
%unquote(__MODULE__){
unquote_splicing(attrs),
values: unquote(values),
values_by_internal_value: unquote(internal_values),
values_by_name: unquote(values_by_name),
}
end
end
# Get the internal representation of an enum value
@doc false
@spec parse(t, any) :: any
def parse(enum, external_value) do
Map.fetch(enum.values_by_name, external_value)
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