storage-engine-playground/crates/README.md

Crates

Each subdirectory is a Cargo package with its own Cargo.toml. Layout:

crates/
  app-name/
    Cargo.toml
    src/
      main.rs

Responsibilities and Dependencies

Crate	Kind	Responsibility	Depends On
storage	library	Backend-agnostic Storage and Transaction traits, plus adapters: MemoryStorage, LmdbStorage, RedbStorage, FjallStorage, SqliteStorage, GeomergeStorage (feature-gated). Owns Value, Table, RowId, StorageError, CodecError.	external geomerge (only with the geomerge feature)
query-ops	library	Snapshot query operators: scan_atom, semijoin, natural_join. Owns Relation, AtomPattern, Term.	storage
plan-runner	library + plan-run CLI	Executes JSON plan IR against a chosen Storage backend via --backend {memory | memory-storage | lmdb | redb | fjall | sqlite | geomerge}. Walks the DAG using query-ops operators and verifies against expected_bindings.	query-ops, storage (all adapter features)
geomerge-demo	binary	End-to-end example exercising GeomergeStorage: theory loading, transactional inserts, scan, persistence round trip, law validation.	storage (with geomerge), external geomerge

The dependency edges form a strict DAG:

storage  ◄── query-ops  ◄── plan-runner
   ▲                              │
   └── geomerge-demo              │
       (also depends on            │
        external geomerge)         │
                                   ▼
                              (all storage features on)

No cycles, no upward dependencies. query-ops and plan-runner are layered above storage; geomerge-demo sits beside them as a runnable example.