Fact.Seam.Adapter behaviour (Fact v0.2.1)

Base behaviour module providing the "glue" between a specific Seam and its implementations.

This module handles:

Resolving allowed and default implementations.
Merging default, fixed, and supplied options for a given implementation.
Initializing a seam instance (Fact.Seam.Instance) with the correct configuration.
Generic dispatch to the underlying implementation via __seam_call__/3.

Responsibilities

Registry Interaction – Uses the seam's registry to resolve implementation modules and versions.
Option Management – Combines fixed options, default options, and user-supplied options and normalizes them.
Instance Creation – Produces a %Fact.Seam.Instance{} struct that encapsulates the module and its initialized state.
Dispatch Helper – Provides __seam_call__/3 to call a function on the underlying seam instance cleanly.

The adapter ensures that only allowed options for a given implementation are used, and merges fixed options that cannot be overridden.

allowed_impls()

default_impl()

registry()

Generic dispatch

@callback allowed_impls() :: [{atom(), pos_integer()}]

@callback default_impl() :: {atom(), pos_integer()}

@callback default_options({atom(), pos_integer()}) :: map()

@callback fixed_options({atom(), pos_integer()}) :: map()

@callback normalize_options(
  {atom(), pos_integer()},
  map()
) :: map()

@callback registry() :: module()

Generic dispatch