Build strategies

ORM::Factory ships four strategies for turning a factory definition into a result. They all share the same surface — (Str:D $name, *@variants, *%overrides) — and dispatch through a small Strategy role.

Method	What it returns	Persists?
build	An unsaved instance.	No
create	A persisted instance.	Yes
attributes-for	A Hash of resolved attributes.	No
build-stubbed	An adapter-stubbed instance (no DB access).	No

my $user  = ORM::Factory.build('user');                  # unsaved
my $saved = ORM::Factory.create('user');                 # persisted
my %h     = ORM::Factory.attributes-for('user');         # attribute hash
my $stub  = ORM::Factory.build-stubbed('user');          # stubbed

Variants

Variants are positional after the factory name:

ORM::Factory.create('user', 'admin');
ORM::Factory.create('user', 'admin', 'active');     # left-to-right, later wins

An unknown variant raises X::ORM::Factory::UnknownVariant.

Per-call overrides

Override any attribute (static or dynamic) by passing a named arg:

ORM::Factory.build('user', :fname<Alice>);
ORM::Factory.build('user', 'admin', :email<a@b.c>);

A Callable override replaces the attribute with a dynamic block evaluated in the evaluator context — so dependent attributes see the override:

ORM::Factory.build('user', :fname<Alice>, :nick({ .fname.uc }));   # 'ALICE'
ORM::Factory.build('user', :fname<Alice>).email;                   # 'alice@example.com'

attributes-for and build-stubbed honour the same overrides.

Collections

ORM::Factory.build-list('user', 3);                      # 3 instances
ORM::Factory.build-list('user', 3, 'admin');             # variant applied to all
ORM::Factory.build-list('user', 3, :fname<X>);           # overrides applied to all
ORM::Factory.build-list('user', 3, -> $u, $i {           # post-build block per instance
  $u.fname = "User$i";
});

The variants form, the overrides form, and the post-build block can be combined freely; the block is recognised by its Callable type at the tail of the positional args.

The same shape works for create-list, build-stubbed-list, and attributes-for-list. The build-pair and create-pair shortcuts are fixed-count *-list variants returning two instances.

Strategy role (ORM::Factory::Strategy)

The public methods dispatch through a small role:

role ORM::Factory::Strategy {
  has $.persistence;
  method to-sym(--> Str) { ... }
  method result(Evaluator $eval) { ... }
  method association(Str:D $name, @variants, %overrides) { ... }
}

The four shipped strategies are BuildStrategy, CreateStrategy, AttributesForStrategy, and BuildStubbedStrategy. Register your own with ORM::Factory.register-strategy — see Custom strategies.