Actor declaration syntax in Swift - Step-by-Step Execution

Concept Flow - Actor declaration syntax

Start

↓

Write 'actor' keyword

↓

Name the actor

↓

Add braces { }

↓

Declare properties and methods inside

↓

Actor ready to use

↓

End

This flow shows how to declare an actor in Swift: start with the 'actor' keyword, give it a name, add braces, then put properties and methods inside.

Execution Sample

Swift

actor Counter {
    var value = 0
    func increment() {
        value += 1
    }
}

Declares an actor named Counter with a value property and an increment method.

Execution Table

Step	Action	Code Part	Result
1	Read 'actor' keyword	actor	Start actor declaration
2	Read actor name	Counter	Actor named 'Counter' created
3	Open braces	{	Begin actor body
4	Declare property	var value = 0	Property 'value' initialized to 0
5	Declare method	func increment() { value += 1 }	Method 'increment' added
6	Close braces	}	Actor declaration complete

💡 Actor declaration ends after closing brace '}'

Variable Tracker

Variable	Start	After Step 4	After Step 5	Final
value	undefined	0	0	0
increment method	undefined	undefined	defined	defined

Key Moments - 3 Insights

Why do we use the 'actor' keyword instead of 'class'?

The 'actor' keyword defines a special type that protects its data from concurrent access, unlike 'class'. See execution_table step 1 where 'actor' starts this special declaration.

Can we declare properties inside the actor?

Yes, properties like 'value' are declared inside the braces as shown in execution_table step 4.

What does the method inside the actor do?

The method 'increment' changes the property 'value' safely inside the actor, as shown in execution_table step 5.

Visual Quiz - 3 Questions

Look at the execution_table, what is the actor's name at step 2?

A increment

B value

C Counter

D actor

💡 Hint

Check the 'Code Part' column at step 2 in execution_table.

At which step is the property 'value' initialized?

A Step 4

B Step 5

C Step 3

D Step 6

💡 Hint

Look for 'var value = 0' in the 'Code Part' column of execution_table.

If we remove the closing brace '}', what happens to the actor declaration?

A It completes normally

B It causes a syntax error

C The actor name changes

D The method is removed

💡 Hint

Refer to exit_note and step 6 in execution_table about the closing brace.

Concept Snapshot

Swift Actor Declaration Syntax:
- Use 'actor' keyword
- Name the actor (e.g., Counter)
- Use braces { } to hold properties and methods
- Properties and methods are isolated for safe concurrency
- Actor protects its data from concurrent access

Full Transcript

This visual execution shows how to declare an actor in Swift. First, the 'actor' keyword is read, starting the declaration. Then the actor is named, for example, 'Counter'. Next, braces are opened to hold the actor's body. Inside, properties like 'value' are declared and initialized. Methods like 'increment' are added to change properties safely. Finally, the closing brace ends the declaration. Actors are special types that protect their data from concurrent access, unlike classes. This step-by-step trace helps beginners see how each part of the actor declaration builds up.