dart behavioral oop, interpreter

add.dart

// Copyright 2024 Fredrick Allan Grott. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

import 'package:interpreter/expression.dart';
import 'package:interpreter/number.dart';

class Add implements Expression {
  @override
  Number number;
  Add(this.number);
  @override
  void interpret(int value) {
    print("Adding $value...");
    number.value += value;
  }
}

expression.dart

// Copyright 2024 Fredrick Allan Grott. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

import 'package:interpreter/number.dart';

abstract class Expression {
  late Number number;
  void interpret(int value);
}

interpreter.dart

// Copyright 2024 Fredrick Allan Grott. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.


import 'package:interpreter/add.dart';
import 'package:interpreter/aubtract.dart';
import 'package:interpreter/number.dart';

void main() {
  var number = Number(0);
  var adder = Add(number);
  var subtracter = Subtract(number);

  adder.interpret(100);
  subtracter.interpret(60);
  adder.interpret(2);

  assert(number.value == 42);
  print("And the result is ${number.value}!");
}

number.dart

// Copyright 2024 Fredrick Allan Grott. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

class Number {
  late int value;
  Number(this.value) {
    print("Starting with $value...");
  }
}

subtract.dart

// Copyright 2024 Fredrick Allan Grott. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

import 'package:interpreter/expression.dart';
import 'package:interpreter/number.dart';

class Subtract implements Expression {
  @override
  Number number;
  Subtract(this.number);
  @override
  void interpret(int value) {
    print("Subtracting $value...");
    number.value -= value;
  }
}