FPP

Functional PHP Preprocessor - Immutable data type generator

What it this?

This library can generate immutable data types based on fpp definitions, the syntax is inspired by Haskell.

YouTube Video Tutorial

Docs

So what really is it?

Create a file and put this in it:

namespace Model\Foo;

data Person = Person { string $name, ?int $age };

This will generate the following php code:

namespace Model\Foo;
final class Person
{
    private $name;
    private $age;

    public function __construct(string $name, ?int $age)
    {
        $this->name = $name;
        $this->age = $age;
    }

    public function name(): string
    {
        return $this->name;
    }

    public function age(): ?int
    {
        return $this->age;
    }

    public function withName(string $name): Person
    {
        return new self($name, $this->age);
    }

    public function withAge(?int $age): Person
    {
        return new self($this->name, $age);
    }
}

Enums?

No problem

namespace MyEnum;

data Color = Red | Blue | Green | Yellow deriving (Enum);

$blue = Color::blue();
var_dump($blue->equals(Color::blue())); // true
var_dump($blue->equals(Color::red())); // false

function (MyEnum\Color $color): string
{
    return $color->value();
}

Enums with value mappings

namespace MyEnum;

data Color = Red | Blue deriving (Enum) with (Red:'someThing', Blue: 13);

var_dump(Color::red()->value()); // 'someThing'
var_dump(Color::blue()->value()); // 13

Derivings

Derivings are kind of PHP's extends keyword, the following rules apply:

It's possible to derive multiple times
Some derivings are not compatible to each other (f.e. Command and ToArray cannot be mixed)

There are 14 deriving types for now:

AggregateChanged
Command
DomainEvent
Enum
Equals
FromArray
FromScalar
FromString
Query
MicroAggregateChanged (not extending from prooph/eventsourcing, f.e. for prooph/micro)
ToArray
ToScalar
ToString
Uuid

Deriving Equals + ToArray

namespace Model\Foo;

data Person = Person { string $name, ?int $age } deriving (ToArray, Equals);

Now you can do this:

$p = new Model\Foo\Person(['name' => 'sasa', 'age' => 36]);
var_dump($p->toArray()); // ['name' => 'sasa', 'age' => 36]
$p->equals($p) // true

Conditions

You can add additional conditions to your code:

namespace Foo;
data FirstName = String deriving (FromString, ToString);
data LastName = String  deriving (FromString, ToString);
data Age = Int deriving (FromScalar, ToScalar);
data Person = Person { FirstName $firstName, LastName $lastName, Age $age } | Boss { FirstName $firstName, LastName $lastName } where
    Person:
        | strlen($lastName->toString()) === 0 => 'last name too short'
        | $age->toScalar() < 18 => "you\'re too young, sorry"
    Boss:
        | strlen($lastName->toString()) < 5 => 'last name too short'
    _:
        | strlen($firstName->toString()) === 0 => 'first name too short';

Usage

php bin/fpp.php <source dir or file>

It will try to find your composer autoload and fetch psr-4 and psr-0 prefixes from it. You'll get an exception, if you want to dump a class, where you have no composer autoload definition.

lunetics/fpp

FPP