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Native dependency injection - Examples

Platform spec article

Native dependency injection - Examples

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Spec standingStandard

Owner
Piotr Mikstacki
Submitter
Piotr Mikstacki

Application host (app target)

Section titled “Application host (app target)”
host AppHost(string[] args) : ConsoleHost {
    registry {
        single AppConfig for Configuration;
        single SqlStorage for Storage;
        single FileStorage for Storage;
    }


    startup(Configuration config, Storage[] storages) {
        for s in storages { s.Open(config); }
    }
}


type StorageAggregator {
    inject Configuration configuration;
    inject Storage[] storages;
}


unit main(string[] args) {
    launch AppHost(args);
}

Library host composed by app

Section titled “Library host composed by app”

Lib project (no launch):

host InfraHost : ConsoleHost {
    registry {
        single SharedLogger for Logger;
    }
}

App project:

host AppHost(string[] args) : InfraHost {
    registry {
        single AppLogger for Logger;   // overrides InfraHost Logger
    }


    startup(Logger logger) { }
}


unit main(string[] args) {
    launch AppHost(args);
}

Named scope with init, dispose, and navigation

Section titled “Named scope with init, dispose, and navigation”
host AppHost(string[] args) : ConsoleHost {
    registry {
        single AppConfiguration for Configuration;
    }


    scope HttpScope(RequestContext request) {
        ScopedDbSession for DbSession;


        init(global::Configuration config, DbSession db) {
            db.Connect(config, request);
        }


        dispose(DbSession db) {
            db.Close();
        }
    }


    startup(Configuration config) { }
}


type RequestWorker {
    inject global::Configuration configuration;


    unit Run(RequestContext request) {
        with HttpScope(request) {
            Process();
        }
    }
}

Plural inject vs singular error

Section titled “Plural inject vs singular error”
registry {
    single A for Provider;
    single B for Provider;
}


type Consumer {
    inject Provider[] providers;   // OK — both A and B
    // inject Provider p;          // E1705 — use array form
}

Nested scopes and independent activations

Section titled “Nested scopes and independent activations”
with HttpScope(request) {
    with UnitOfWork(readOnly: false) { Save(); }
}
with HttpScope(request) {
    with UnitOfWork(readOnly: true) { Query(); }   // second activation — new scoped set
}

Conformance fixtures under compiler/crates/beskid_tests and compiler/crates/beskid_e2e_tests will track the reference implementation as composition analysis lands.