Memory/Enum-based CQL adapter for plain structs.

This is the fallback adapter when no other adapter (Ecto, Elasticsearch, etc.) matches the struct backing a type. It provides basic CQL operations using Elixir's Enum module functions.

Supported Operations

Filter Operators:

• _eq - Equality check (==)
• _neq - Not equal (!=)
• _gt, _gte, _lt, _lte - Comparisons (>, >=, <, <=)
• _in - Value in list
• _nin - Value not in list
• _is_null - Null check

Sort:

• asc - Sort ascending
• desc - Sort descending

How It Works

Unlike database adapters, the Memory adapter works on in-memory lists:

users = [%User{id: 1, name: "Alice"}, %User{id: 2, name: "Bob"}]

# Filter: name == "Alice"
Memory.filter(users, :name, :_eq, "Alice")
#=> [%User{id: 1, name: "Alice"}]

# Sort by name ascending
Memory.sort(users, :name, :asc)
#=> [%User{id: 1, name: "Alice"}, %User{id: 2, name: "Bob"}]

Usage with GreenFairy

This adapter is automatically selected for types that:

• Use plain structs (not Ecto schemas)
• Don't have a repo configured
• Don't match any other adapter

Users must provide their own data source (typically via resolver):

type "User", struct: MyApp.User do
  # CQL operators are available for filtering/sorting
  # but you provide the data in your resolver
  field :id, non_null(:id)
  field :name, :string
end

# In your resolver:
def list_users(_parent, args, _ctx) do
  users = MyApp.get_all_users()
  filtered = GreenFairy.CQL.Adapters.Memory.apply_filters(users, args.filter)
  sorted = GreenFairy.CQL.Adapters.Memory.apply_order(filtered, args.order)
  {:ok, sorted}
end