https://github.com/kudashevs/calculator-via-magic
A simple calculator app that implements math operations via a magic _call method.
https://github.com/kudashevs/calculator-via-magic
case-study magic-methods php
Last synced: 3 months ago
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A simple calculator app that implements math operations via a magic _call method.
- Host: GitHub
- URL: https://github.com/kudashevs/calculator-via-magic
- Owner: kudashevs
- License: mit
- Created: 2019-10-08T13:56:44.000Z (over 5 years ago)
- Default Branch: master
- Last Pushed: 2023-09-29T16:06:24.000Z (over 1 year ago)
- Last Synced: 2025-01-21T16:38:42.770Z (4 months ago)
- Topics: case-study, magic-methods, php
- Language: PHP
- Homepage:
- Size: 52.7 KB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE.md
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README
# Calculator Via Magic
This is a case study that aims to show one of the possible ways of using magic methods in PHP language.
## How it works
We are given a [Calculator](src/Calculator.php) class with the only one `__call` method. This is so-called "magic method",
which is triggered when an inaccessible method is called on an object. This magic method accepts the name of a method being
called and an array of the provided arguments. When the `__call` method is triggered, a `Calculator` instance is trying
to identify an `Operation` that corresponds to the received method name. If the suitable `Operation` exists, a Factory
creates an instance of the operation and the `Calculator` class performs calculations using this instance. If not, it
throws an exception as if there were no such method.
```php
$calculator = new Calculator();
echo $calculator->addition(1, 2); // results in 3
```
for more usage examples, please see the [examples](examples/) folder.
## Notes
By default, the package provides four classes that correspond to the basic math operations (addition, subtraction,
multiplication, division). Each class extends an `Operation` class. The `Operation` class is an abstract class that
obliges its subclasses to implement the `performCalculation` method. It also provides default implementations for
`calculate` and `validate` methods. The `Division` class overrides the default implementation of the `validate` method
and extends its functionality. For more information see the [Operations](src/Operations/) folder.
The validation of input arguments is implemented in the [Operation](src/Operations/Operation.php) abstract class. By using
the `final` keyword and the inheritance, we force all the `Operation` implementations to use the predefined validation.
A lookup table for supported operations is kept as a constant in the [Factory.php](src/Operations/Factory.php) file.
## Things to learn
[//]: # (@todo don't forget to update the line numbers)
Things that you can learn from this case study:
- magic methods, how they work, and [how you can use them](src/Calculator.php#L37)
- how to [use the factory pattern](src/Operations/Factory.php) (one of the possible implementations)
- how to [use final to force the subclasses to use predefined behavior](src/Operations/Operation.php#L23)
- how to [override and extend methods inherited from the base class](src/Operations/Division.php#L28)
## License
The MIT License (MIT). Please see the [License file](LICENSE.md) for more information.