Add new one concept example that uses full syntax

examples/concept_full_syntax.py

@@ -0,0 +1,67 @@
+"""Concept example of `Dependency Injector`."""
+
+import sqlite3
+
+from dependency_injector import catalogs
+from dependency_injector import providers
+from dependency_injector import injections
+
+
+class UsersService(object):
+    """Users service, that has dependency on database."""
+
+    def __init__(self, db):
+        """Initializer."""
+        self.db = db
+
+
+class AuthService(object):
+    """Auth service, that has dependencies on users service and database."""
+
+    def __init__(self, db, users_service):
+        """Initializer."""
+        self.db = db
+        self.users_service = users_service
+
+
+class Services(catalogs.DeclarativeCatalog):
+    """Catalog of service providers."""
+
+    database = providers.Singleton(sqlite3.connect,
+                                   injections.Arg(':memory:'))
+    """:type: providers.Provider -> sqlite3.Connection"""
+
+    users = providers.Factory(UsersService,
+                              injections.KwArg('db', database))
+    """:type: providers.Provider -> UsersService"""
+
+    auth = providers.Factory(AuthService,
+                             injections.KwArg('db', database),
+                             injections.KwArg('users_service', users))
+    """:type: providers.Provider -> AuthService"""
+
+
+# Retrieving catalog providers:
+users_service = Services.users()
+auth_service = Services.auth()
+
+# Making some asserts:
+assert users_service.db is auth_service.db is Services.database()
+assert isinstance(auth_service.users_service, UsersService)
+assert users_service is not Services.users()
+assert auth_service is not Services.auth()
+
+
+# Making some "inline" injections:
+@injections.inject(users_service=Services.users)
+@injections.inject(auth_service=Services.auth)
+@injections.inject(database=Services.database)
+def example(users_service, auth_service, database):
+    """Example callback."""
+    assert users_service.db is auth_service.db
+    assert auth_service.db is database
+    assert database is Services.database()
+
+
+# Making a call of decorated callback:
+example()