Some examples for how to build dart code using package:analyzer and package:code_builder only (i.e. no build_runner or build.yaml files)

What is this?

Some examples for how to build dart code from another dart code using package:analyzer and package:code_builder only (i.e. no build_runner or build.yaml files).

In the example folder, there are three different stand-alone examples. Each one of them can be simply executed as follow:

[~/path/to/repo] dart run example/<file_name>.dart

• ast_example
  • Shows how an Abstract Syntax Tree (AST) can be generated from a source code using package:analyzer.
  • How to visit elements in the tree.

• code_builder
  • Shows how to build code programmatically using package:code_builder

• data_class_builder_example

  • combines both examples to generate a data class.

  • In short, it takes this as an input:

  class Person  { 
      final String name;
      final String? nickname;
      final int age;
      final double height;
      final List<String> hobbies;
  }

  • To generate this as an output:
    
    

  class Person {
      const Person({
          required this.name,
          this.nickname,
          required this.age,
          required this.height,
          required this.hobbies,
      });
  
      factory Person.fromMap(Map<String, dynamic> map) {
          return Person(
          name: map['name'],
          nickname: map['nickname'],
          age: map['age'].toInt(),
          height: map['height'].toDouble(),
          hobbies: List.from(map['hobbies']),
          );
      }
  
      factory Person.fromJson(String source) => Person.fromMap(json.decode(source));
  
      final String name;
  
      final String? nickname;
  
      final int age;
  
      final double height;
  
      final List<String> hobbies;
  
      Person copyWith({
          String? name,
          String? nickname,
          int? age,
          double? height,
          List<String>? hobbies,
      }) {
          return Person(
          name: name ?? this.name,
          nickname: nickname ?? this.nickname,
          age: age ?? this.age,
          height: height ?? this.height,
          hobbies: hobbies ?? this.hobbies,
          );
      }
  
      String toJson() => json.encode(toMap());
      Map<String, dynamic> toMap() {
          return {
          'name': name,
          'nickname': nickname,
          'age': age,
          'height': height,
          'hobbies': hobbies,
          };
      }
  
      @override
      String toString() {
          return 'Person(name: $name, nickname: $nickname, age: $age, height: $height, hobbies: $hobbies)';
      }
  
      @override
      bool operator ==(Object other) {
          if (identical(this, other)) return true;
          // TODO: handle list equality here
          return other is Person &&
              other.name == name &&
              other.nickname == nickname &&
              other.age == age &&
              other.height == height &&
              other.hobbies == hobbies;
      }
  
      @override
      int get hashCode {
          return name.hashCode ^ nickname.hashCode ^ age.hashCode ^ height.hashCode ^ hobbies.hashCode;
          }
  }
  

Disclimar: These examples were written (poorly) for learning purposes and to understand how these packages work together -- no more no less.