Enums

An enum maps a column's stored value to a set of symbolic names. The column holds the backing value (an integer or a string); the model works in terms of the names.

Declaring#

Declare an enum in the model's submethod BUILD, alongside attributes, validations, and associations. The first argument is the column; the second maps each symbolic name to its backing value.

class Order is Model {
  method table-name { 'orders' }

  submethod BUILD {
    self.enum: 'status', { active => 0, archived => 9 };
    self.enum: 'state',  { open => 'open', closed => 'closed' };
  }
}

Backing values may be integers or strings, and the integers need not be contiguous. A column with no enum keeps its raw value.

Reading and writing#

The reader returns the symbolic name; the column stores the backing value:

my $order = Order.create({ status => 'active' });
$order.status;          # 'active'
# the orders.status column holds 0

Assigning either a name or a backing value normalises to the name in memory:

Order.create({ status => 9 }).status;    # 'archived'

Predicates and the bang setter#

Each value gets a predicate and a setter. The predicate is-<value> reports whether that value is current. The setter <value>-bang assigns the value and saves the record.

$order.is-active;       # True
$order.is-archived;     # False

$order.archived-bang;   # sets status to 'archived' and saves

The bang suffix stands in for a trailing ! (Raku method names cannot end in !).

Class scopes#

Each value adds a class scope returning a relation filtered to that value:

Order.active.all;       # orders whose status is active
Order.archived.all;
Order.closed.all;       # works for text-backed enums too

Inspecting#

enum-values('status') lists the symbolic names declared for a column.

Order.enum-values('status');    # ('active', 'archived')

State machines#

There is no built-in state-machine DSL — it is out of scope for the ORM core. Model a state column with an enum and guard the transitions with validations and callbacks, or reach for a dedicated state-machine library when you need guards, events, and transition callbacks as first-class concepts.