Per-call overrides

Every build method — build, create, attributes-for, build-stubbed, and their -list / -pair cousins — accepts named arguments that override attributes for that call only. The original definition is untouched.

Static override of a static attribute

define {
  .factory: 'profile', {
    .fname: 'Greg';
    .nick:  'gd';
  };
};

ORM::Factory.build('profile', :fname<Alice>).fname;   # 'Alice'
ORM::Factory.build('profile', :fname<Alice>).nick;    # 'gd'  (untouched)

Static override of a dynamic attribute

A static override replaces a block defined on the factory with the literal value:

define {
  .factory: 'profile', {
    .fname: 'Greg';
    .email: { .fname.lc ~ '@example.com' };
  };
};

ORM::Factory.build('profile', :email<[email protected]>).email;   # '[email protected]'

Block override

Pass a callable to override with a fresh block. The block runs against the evaluator, so it can read other attributes via $_:

ORM::Factory.build('profile', :fname<Alice>, :nick({ .fname.uc })).nick;
# 'ALICE'

Overrides apply uniformly across all four build strategies:

ORM::Factory.attributes-for('profile', :fname<Carol>)<fname>;   # 'Carol'
ORM::Factory.create('profile',         :fname<Carol>).fname;    # 'Carol'
ORM::Factory.build-stubbed('profile',  :fname<Carol>).fname;    # 'Carol'

Dependent attributes see the override

The override goes through the evaluator before any dependent attribute is resolved, so a block that reads .fname sees the overridden value:

ORM::Factory.build('profile', :fname<Alice>).email;
# '[email protected]'