Implemented feature: @ToStringMixin() (#42)

* Implemented feature: `@ToStringMixin()`
* Updated package description
* Updated documentation for`@ToStringMixin()` and fixed some minor typos
* Updated all to version 1.1.0

README.md

@@ -1,5 +1,5 @@
 # to_string_helper
-Flexibly configure output of `toString` method (with or without code generation).
+Flexibly configure output of `toString` method (with or without code generation) (with or without mixin).
 
 You can choose either to use code generator or not.
 

example_with_generator/lib/example.dart

@@ -1 +1,2 @@
 export 'src/bike.dart';
+export 'src/car.dart';

example_with_generator/lib/main.dart

@@ -1,6 +1,8 @@
 import 'src/bike.dart';
+import 'src/car.dart';
 
 main() {
   print(Bike());
   print(EBike());
+  print(Car());
 }

example_with_generator/lib/src/car.dart

@@ -0,0 +1,17 @@
+import 'package:to_string_helper/to_string_helper.dart';
+
+import 'vehicle.dart';
+
+part 'car.g.dart';
+
+@ToStringMixin(
+  globalInclude: Include(static: true, nullValue: false),
+  unnamedValue: true,
+)
+class Car extends Vehicle with _$CarToString {
+  static String name = 'Car';
+  @ToStringField(includeNullValue: true, unnamedValue: false)
+  String _engine;
+  String color;
+  final wheels = 4;
+}

example_with_generator/pubspec.yaml

@@ -1,5 +1,5 @@
 name: to_string_helper_example_with_generator
-version: 1.0.3
+version: 1.1.0
 
 environment:
   sdk: ">=2.0.0 <3.0.0"

example_with_generator/test/src/bike_test.dart → example_with_generator/test/to_string_test.dart

@@ -97,4 +97,10 @@ void main() {
       });
     });
   });
+
+  group('@ToStringMixin()', () {
+    test('Car', () {
+      expect(Car().toString(), 'Car{Car, _engine=null, 4}');
+    });
+  });
 }

example_without_generator/pubspec.yaml

@@ -1,5 +1,5 @@
 name: to_string_helper_example_without_generator
-version: 1.0.3
+version: 1.1.0
 
 environment:
   sdk: ">=2.0.0 <3.0.0"

generator/CHANGELOG.md

@@ -1 +1,5 @@
+# 1.1.0
+* Generate code for annotation `@ToStringMixin`.
+
 # 1.0.3
+* Generate code for annotations: `@ToString` and `@ToStringField`.

generator/lib/src/config_helper.dart

@@ -19,7 +19,14 @@ const defaultInclude = Include(
 );
 
 Config getConfig(ConstantReader annotation, ClassElement classElement) {
+  if (!_isToString(annotation)) {
+    throw InvalidGenerationSourceError(
+        'Target class should only be annotated with @ToString() or @ToStringMixin()',
+        element: classElement);
+  }
+
   return Config(
+    mixin: _isToStringMixin(annotation),
     format: FormatConfig(
       nullString: _peek(annotation, 'nullString')?.stringValue ??
           defaultFormatConfig.nullString,
@@ -170,3 +177,13 @@ ConstantReader _getFieldAnnotation(FieldElement element, Type annotationType) {
 
   return null;
 }
+
+bool _isToString(ConstantReader annotation) {
+  return annotation?.instanceOf(const TypeChecker.fromRuntime(ToString)) ??
+      false;
+}
+
+bool _isToStringMixin(ConstantReader annotation) {
+  return annotation?.instanceOf(const TypeChecker.fromRuntime(ToStringMixin)) ??
+      false;
+}

generator/lib/src/configs/config.dart

@@ -4,18 +4,25 @@ import 'field_config.dart';
 import 'format_config.dart';
 
 class Config {
-  const Config({this.format, this.globalInclude, this.fields});
+  const Config({
+    this.format,
+    this.globalInclude,
+    this.fields,
+    this.mixin = false,
+  });
 
   final FormatConfig format;
   final Include globalInclude;
   final Set<FieldConfig> fields;
+  final bool mixin;
 
   @override
   String toString() {
     return 'Config{'
         'format: $format'
         ', globalInclude: $globalInclude'
         ', fields: $fields'
+        ', mixin: $mixin'
         '}';
   }
 }

generator/lib/src/to_string_generator.dart

@@ -14,12 +14,22 @@ class ToStringGenerator extends GeneratorForAnnotation<ToString> {
       Element element, ConstantReader annotation, BuildStep buildStep) async {
     if (element is! ClassElement) {
       throw InvalidGenerationSourceError(
-          '@ToString() should only be annotated on class target',
+          '@ToString() should only be annotated on target class',
           element: element);
     }
     final clazz = element as ClassElement;
 
-    return _generateToStringMethod(clazz, getConfig(annotation, clazz));
+    return _generateCode(clazz, getConfig(annotation, clazz));
+  }
+
+  String _generateCode(ClassElement clazz, Config config) {
+    if (config.mixin) {
+      return _generateToStringMethod(clazz, config) +
+          '\n\n' +
+          _generateToStringMixin(clazz.name);
+    } else {
+      return _generateToStringMethod(clazz, config);
+    }
   }
 
   String _generateToStringMethod(ClassElement clazz, Config config) {
@@ -79,6 +89,32 @@ class ToStringGenerator extends GeneratorForAnnotation<ToString> {
     return sb.toString();
   }
 
+  String _generateToStringMixin(String classname) {
+    final mixinName = _getToStringMixinName(classname);
+    final methodName = _getToStringMethodName(classname);
+
+    final sb = StringBuffer();
+
+    // start mixin
+    sb.writeln('mixin $mixinName {');
+
+    // mixin body
+    sb
+      ..writeln('@override')
+      ..writeln('String toString() {')
+      ..writeln('return $methodName(this);')
+      ..writeln('}');
+
+    // close mixin
+    sb.writeln('}');
+
+    return sb.toString();
+  }
+
+  String _getToStringMixinName(String classname) {
+    return '_\$${classname}ToString';
+  }
+
   String _getToStringMethodName(String classname) {
     return '_\$' +
         classname[0].toLowerCase() +

generator/pubspec.yaml

@@ -1,6 +1,8 @@
 name: to_string_helper_generator
-version: 1.0.3
-description: Generate code for package to_string_helper. This package is not needed if you want to use to_string_helper without code generation.
+version: 1.1.0
+description: >
+  Generate code for package to_string_helper.
+  This package is not needed if you want to use to_string_helper without code generation.
 homepage: https://github.com/zenonine/to_string_helper
 repository: https://github.com/zenonine/to_string_helper/tree/master/generator
 
@@ -12,3 +14,7 @@ dependencies:
   analyzer: ^0.39.7
   build: ^1.0.0
   source_gen: ^0.9.5
+
+#dependency_overrides:
+#  to_string_helper:
+#    path: ../to_string_helper

to_string_helper/CHANGELOG.md

@@ -1,3 +1,6 @@
+# 1.1.0
+* Added annotation `@ToStringMixin`.
+
 # 1.0.5
 * Improved documentation.
 

to_string_helper/README.md

@@ -1,5 +1,5 @@
 # to_string_helper
-Flexibly configure output of `toString` method (with or without code generation).
+Flexibly configure output of `toString` method (with or without code generation) (with or without mixin).
 
 You can choose either to use code generator or not.
 
@@ -46,6 +46,17 @@ Otherwise, you only need this package.
        to_string_helper_generator: ^1.0.0
    ```
 2. Configure your class
+* With mixin
+   ```dart
+   import 'package:to_string_helper/to_string_helper.dart';
+
+   // assume current file is bike.dart, the generated code should be in bike.g.dart
+   part 'bike.g.dart';
+
+   @ToStringMixin()
+   class Bike {/*...*/}
+   ```
+* Without mixin
    ```dart
    import 'package:to_string_helper/to_string_helper.dart';
 
@@ -59,6 +70,19 @@ Otherwise, you only need this package.
     * `pub run build_runner build`: run a single build and exit.
     * `pub run build_runner watch`: continuously run builds as you edit files.
 4. Use the generated code to produce output of `toString`
+* With mixin
+   ```dart
+   import 'package:to_string_helper/to_string_helper.dart';
+
+   part 'bike.g.dart';
+
+   @ToStringMixin()
+   class Bike with _$BikeToString {
+     final hasEngine = false;
+     final wheels = 2;
+   }
+   ```
+* Without mixin
    ```dart
    import 'package:to_string_helper/to_string_helper.dart';
 
@@ -212,9 +236,12 @@ Otherwise, you only need this package.
     * `Include` in `inclusion` map and `globalInclude` are then merged.
       Below is an example how the attribute `nullValue` is merged.
         * If `inclusion[Bike].nullValue == null`, use `globalInclude.nullValue`.
-        * If `globalInclude.nullValue == null`, use the fallback value (see [default configuration](#default-configuration)).
+        * If `globalInclude.nullValue == null`, use the fallback value
+          (see [default configuration](#default-configuration)).
 
 # Default configuration
+* Configuration of `@ToString` and `@ToStringMixin` is exactly identical.
+  `@ToStringMixin` generates the same code as `@ToString` and additionally a mixin class.
 * The 2 examples below are treated equally:
   ```dart
   @ToString()
@@ -240,9 +267,11 @@ Otherwise, you only need this package.
     * `static`: `false`
     * `public`: `true`
     * `private`: `false`
-* `@ToStringField()`, `@ToStringField(exclude: false)` or `@ToStringField(exclude: null)` are treated equally. It means, force to include the field regardless of configuration in `@ToString()`.
+* `@ToStringField()`, `@ToStringField(exclude: false)` or `@ToStringField(exclude: null)` are treated equally.
+  It means, force to include the field regardless of configuration in `@ToString()`.
 * `@ToStringField(exclude: true)`: force to exclude the field regardless of configuration in `@ToString()`.
-* `ToStringField.includeNullValue == null` means inheriting `Include.nullValue` from `@ToString()` after merging `globalInclude` and `inclusion`.
+* `ToStringField.includeNullValue == null` means inheriting `Include.nullValue` from `@ToString()`
+  after merging `globalInclude` and `inclusion`.
 * `ToStringField.truncate == null` means inheriting `ToString.truncate`.
 * `ToStringField.unnamedValue == null` means inheriting `ToString.unnamedValue`.
 

to_string_helper/example/example.md

@@ -34,8 +34,22 @@
     build_runner: ^1.0.0
     to_string_helper_generator: ^1.0.0
   ```
+* `bike.dart` with mixin
+  ```dart
+  import 'package:to_string_helper/to_string_helper.dart';
 
-* `bike.dart`
+  part 'bike.g.dart';
+
+  // Name of the generated mixin is in format _$<ClassName>ToString  
+  @ToStringMixin()
+  class Bike with _$BikeToString {
+    final hasEngine = false;
+
+    @ToStringField(exclude: true)
+    final wheels = 2;
+  }
+  ```
+* `bike.dart` without mixin
   ```dart
   import 'package:to_string_helper/to_string_helper.dart';
 

to_string_helper/lib/src/annotations/to_string_mixin.dart

@@ -0,0 +1,19 @@
+import 'include.dart';
+import 'to_string.dart';
+
+class ToStringMixin extends ToString {
+  const ToStringMixin({
+    Include globalInclude,
+    Map<Type, Include> inclusion,
+    String nullString = 'null',
+    String separator = ', ',
+    int truncate = 0,
+    bool unnamedValue = false,
+  }) : super(
+            globalInclude: globalInclude,
+            inclusion: inclusion,
+            nullString: nullString,
+            separator: separator,
+            truncate: truncate,
+            unnamedValue: unnamedValue);
+}

to_string_helper/lib/to_string_helper.dart

@@ -1,4 +1,5 @@
 export 'src/annotations/include.dart';
 export 'src/annotations/to_string.dart';
 export 'src/annotations/to_string_field.dart';
+export 'src/annotations/to_string_mixin.dart';
 export 'src/to_string_helper.dart';

to_string_helper/pubspec.yaml

@@ -1,6 +1,6 @@
 name: to_string_helper
-version: 1.0.5
-description: Flexibly configure output of toString method (with or without code generation).
+version: 1.1.0
+description: Flexibly configure output of toString method (with or without code generation) (with or without mixin).
 homepage: https://github.com/zenonine/to_string_helper
 repository: https://github.com/zenonine/to_string_helper/tree/master/to_string_helper