Protocol for defining types in Zoi.

Types are used to validate and parse data according to a defined schema. You can implement this protocol for custom types to handle specific validation and parsing logic.

Example

To create a custom type, you can define a module and implement the Zoi.Type protocol:

defmodule StringBoolean do
  use Zoi.Type.Def

  # `apply_type/1` is a helper function that will create the struct with the given options.
  def string_bool(opts \\ []) do
    apply_type(opts)
  end

  defimpl Zoi.Type do
    # This function is called to parse the input according to the schema.
    def parse(schema, input, opts) when is_binary(input) do
      {:ok, input}
    end

    def parse(schema, input, opts) when is_boolean(input) do
      {:ok, input}
    end

    def parse(_schema, _input, _opts) do
      {:error, "invalid string or boolean type"}
    end
  end
end

You can then use this type in your schema definitions and it will handle parsing and validation as defined.

iex> schema = StringBoolean.string_bool()
iex> Zoi.parse(schema, "hello world")
{:ok, "hello world"}
iex> Zoi.Type.parse(schema, true)
{:ok, true}
iex> Zoi.Type.parse(schema, 123)
{:error, %Zoi.Error{message: "invalid string or boolean type"}}