Ecto adapter for Dequel queries. Converts parsed AST to Ecto dynamic queries.

Relational Query Handling

Relational queries like author.name:Tolkien are handled in three steps:

1. Path Detection & Join Tracking

When build_filter receives an AST node with a path (list of atoms like [:author, :name]), it calls Context.ensure_joins/2 to register the needed joins. The path is split: [:author] becomes the join path, :name is the field to filter on. The context returns a binding name like :join_author.

2. Dynamic Expression with Named Binding

The build_dynamic functions create Ecto dynamic expressions that reference the joined table via named binding:

dynamic([{^binding, x}], field(x, ^field) == ^value)

The [{^binding, x}] syntax binds x to the table with that alias.

3. Query Assembly

The query/3 function assembles everything:

1. Wraps base query with :q alias via ensure_base_alias/1
2. Applies LEFT JOINs in dependency order via apply_joins/2
3. Adds the WHERE clause with the dynamic expression
4. Optionally adds preloads

Example Flow

For query "author.name:Tolkien":

1. Parser produces: {:==, [], [[:author, :name], "Tolkien"]}
2. Context.ensure_joins/2 registers join for [:author] → returns :join_author
3. build_dynamic/4 creates: dynamic([{:join_author, x}], field(x, :name) == "Tolkien")
4. apply_joins/2 adds: join(:left, [{:q, p}], a in assoc(p, :author), as: :join_author)
5. Final query filters on the joined author's name field