Enums

Enums

About

• Enums define fixed sets of values.
• Lightweight alternative to classes.
• Support methods and properties.
• Enable exhaustive switching.

Main Topics

1. Basic Enum

   • Definition: enum keyword.
   • Example:

     enum Status { pending, approved, rejected }

2. Enhanced Enums

   • **Definition`: Members and methods.

   • Example:

     enum Status {
       pending('Pending'),
       approved('Approved');
     
       final String label;
       const Status(this.label);
     }

3. Pattern Matching

   • **Definition`: Exhaustive switches.
   • Example:

     String describe(Status s) => switch(s) {
       Status.pending => 'Waiting',
       Status.approved => 'Confirmed'
     };

4. State Representation

   • **Definition`: Finite state machines.
   • Example:

     enum AuthState { loggedOut, loggedIn }

How to Use

• Declare: Simple value lists
• **Enhance`: Add properties/methods
• **Switch`: Exhaustive pattern matching
• **Convert: name` property for strings

How It Works

• **Values`: Fixed at compile-time
• **Safety`: Compiler knows all cases
• **Performance`: More efficient than strings

Example Session:

void main() {
  var status = Status.pending;
  print(status.label); // Enhanced enum property
}

Conclusion

Dart enums evolve beyond simple value sets into powerful state modeling tools through enhanced capabilities and pattern matching support.