https://github.com/kudashevs/calculator-via-closure
A simple calculator app that implements math operations via a closure function.
https://github.com/kudashevs/calculator-via-closure
case-study closures php
Last synced: 3 months ago
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A simple calculator app that implements math operations via a closure function.
- Host: GitHub
- URL: https://github.com/kudashevs/calculator-via-closure
- Owner: kudashevs
- License: mit
- Created: 2018-09-29T22:30:03.000Z (over 6 years ago)
- Default Branch: master
- Last Pushed: 2023-09-29T15:57:07.000Z (over 1 year ago)
- Last Synced: 2025-01-21T16:38:43.492Z (5 months ago)
- Topics: case-study, closures, php
- Language: PHP
- Homepage:
- Size: 56.6 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 Closures
This is a case study that aims to show one of the possible ways of using closures in PHP language.
## How it works
We are given a [calculator()](src/calculator.php) function that accepts an argument (a `callable` with at least one argument).
To start using the closure, we need to provide an argument of the callable type with a predefined functionality (a math operation
in our case) to the `calculator()` function, and assign the result to a variable. The function is going to enclose/remember
the provided callable argument as a part of its context and is going to use it each time the closure is invoked.
```php
$addition = calculator($opaddition);
echo $addition(1, 2); // results in 3
```
for more usage examples, please see the [examples](examples/) folder.
## Notes
By default, the package uses a bootstrap that registers four global variables that correspond to the basic math operations
(addition, subtraction, multiplication, division). These variables have an `op-` prefix in their names (i.e. `$opaddition`)
and refer to variadic anonymous functions. For more information see the [bootstrap.php](src/Operations/bootstrap.php) file).
The validation of input arguments is implemented in the `checkValidArguments` function in the [calculator.php](src/calculator.php) file.
**Note** The decomposition might look strange, and it really is. However, this is just a study case on how we can use a closure
to assign some predefined behavior to a variable.
## Things to learn
[//]: # (@todo don't forget to update the line numbers)
Things that you can learn from this case study:
- closures, how they behave, and [how you can use them](src/calculator.php#L16)
- how to [check the number of arguments of a callable](src/calculator.php#L25)
- how to [register variables in the global scope](src/Operations/bootstrap.php#L32)
## License
The MIT License (MIT). Please see the [License file](LICENSE.md) for more information.