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,
            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,
        String toString() {
            return 'Person(name: $name, nickname: $nickname, age: $age, height: $height, hobbies: $hobbies)';
        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;
        int get hashCode {
            return name.hashCode ^ nickname.hashCode ^ age.hashCode ^ height.hashCode ^ hobbies.hashCode;

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


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