Generics

Generics

About

• Generics enable type-safe abstractions.
• Parameterize classes and methods.
• Reusable across different types.
• Foundation of collection types.

Main Topics

1. Generic Classes

   • Definition: Type parameters.
   • Example:

     class Box<T> {
       final T value;
       Box(this.value);
     }

2. Generic Methods

   • Definition: Method-level type params.
   • Example:

     T first<T>(List<T> items) => items[0];

3. Collection Types

   • Definition: Built-in generic collections.
   • Example:

     List<String> names = ['a', 'b'];
     Map<String, int> scores = {'a': 100};

4. Bounded Types

   • **Definition`: Constraining type params.
   • Example:

     class NumberBox<T extends num> {...}

How to Use

• Declare: Use angle brackets <T>
• Constrain: extends for bounds
• Instantiate: Provide concrete types
• Infer: Let Dart deduce types

How It Works

• Reification: Retains type at runtime
• Safety: Prevents type errors
• **Performance`: No boxing overhead

Example Session:

void main() {
  var box = Box<int>(42); // Explicit type
  var names = ['a', 'b']; // Inferred List<String>
}

Conclusion

Generics provide type-safe abstraction without sacrificing performance, enabling reusable code that maintains strict type checking throughout Dart applications.