Inline Symbols

Inline symbols indicate references within a line.

@ (Actor)

Reference to a machine/actor:

machine: @order
on :checkout from @customer (api)
emit :request to @payment

: (Event)

Reference to an event:

on :checkout from @customer (api)
emit :payment_request to @payment
on :payment_success from @payment

# (State)

Reference to a machine state:

order moves to #pending
? order is in #paid
order transitions to #completed

$ (Context Variable)

Reference to context data:

$total becomes 100
$items adds "Laptop"
? $total > 0

With type annotation:

$total: number becomes 100
$items: array adds "Laptop"

Type Annotations

Optional types for context variables:

Type	Description	Example
string	Text values	$name: string becomes "John"
number	Integers and decimals	$total: number becomes 100
boolean	True/false	$active: boolean becomes true
array	List of items	$items: array becomes empty
object	Key-value pairs	$config: object becomes empty

^ (Binding Transformer)

Reference to a binding transformer for complex response transformations:

on :get_order_report from @admin (api)
  reply 200 with ^order_report

Binding transformers:

• Execute code that transforms response data
• Handle complex business logic not expressible in EventFlow
• Map to PHP/JS classes with the #[ResponseTransformer] attribute

#[ResponseTransformer('order_report')]
class OrderReportTransformer {
    public function transform(Context $context): array {
        return [
            'summary' => $this->buildSummary($context),
            'charts' => $this->generateChartData($context),
        ];
    }
}

See Machine Responses for details.