Estructura type scaffold for creating validatable and coercible types for structs.

This module provides a way to create custom types for structs.

Usage

There are two ways to use this type scaffold:

1. Using the module directly

iex> require Estructura.Nested.Type.Struct
...> Estructura.Nested.Type.Struct.type_module_ast(Type.Money, [origin: Money]
...> apply(Type.Money, :validate, [Money.new!("100", :USD)])
{:ok, :pending}
iex> apply(Status, :validate, [:invalid])
{:error, "Expected :invalid to be an instance of `Money` struct"}

2. Using the use macro

iex> defmodule Price do
...>   use Estructura.Nested.Type.Struct, origin: Money
...> end
...> Role.validate(:admin)
{:ok, :admin}

Configuration Options

The scaffold accepts the following options:

• :origin - (required) The actual struct to be wrapped
• :coercer - (optional) Function to coerce input values
• :encoder - (optional) Function to encode values for JSON

Example with Custom Coercion

defmodule Price do
  use Estructura.Nested.Type.Struct,
    origin: Money,
    coercer: fn
      %Money{} = price -> {:ok, price}
      {amount, currency} -> with %Money{} = price <- Money.new(amount, currency), do: {:ok, price}
      other -> {:error, "Cannot coerce #{inspect(other)} to price"}
    end
end

Generated Functions

The scaffold implements the Estructura.Nested.Type behaviour and provides:

• generate/1 - Generates random values from the enum for testing
• coerce/1 - Attempts to convert input into a valid enum value
• validate/1 - Ensures a value is part of the enum

Generation Options

TBD