Pure Expressive

A simple but powerful module loader written for PHP.

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Getting Started

Requirements

• Docker: Required to use ./play script (app/console will work with PHP 7.4).

Installation

git clone https://github.com/userdude/pure-expressive.git pure-expressive

cd pure-expressive

./play make/service say/hello

Now you can edit the app/say/hello.php file and change the service's return statement at the end of the generated file:

<?php // app/say/hello.php

...

return fn(?string $name = null): string => sprintf('Hello %s!', $name ?: 'world');

Now call it:

$ ./play say/hello Jim
Hello Jim!

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About the Project

This is the most basic version of the Pure Expressive project I've been working on for a while. The objective is to show as minimal as possible example of module loading using a more modern PHP syntax and controllable environment (container).

Overall, the service implementation with script execution is <200 lines of code. By itself this isn't too interesting. To a large degree I consider this a replacement for pretty much any container requirement except where a package expressly needs a container. Which of course you can add a service to get one for you. Really is that easy. :D

First, let's look at our files.

• play: Calls a console service against the app/console php script.
• worker: This command starts a worker session that play uses to run the service request. This provides a consistent PHP version (7.4 as of now).

This basic, compat-level expressive only has one folder, and two more files:

• app/: Directory with our service definitions.
• app/console: Used to call service commands directly from the command line.
• app/make/service.php: A simple make script.

Important! A service name is always minus the app/ and .php. For instance, app/make/service/php would become make/service, as in ./play make/service ....

Now let's create our first service. For example, a foo/bar service:

./play make/service foo/bar

Running that in the console, you should receive something like:

$ ./play make/service foo/bar
Success! app/foo/bar.php service file generated.

That file is now in your app/foo directory, which was also created.

Opening the app/foo/bar.php file, you should see this:

<?php

declare(strict_types=1);

namespace App\Foo;

interface Bar {
    public function __invoke();
}

return function() use(&$context) {
    // TODO: Make foo/bar happen.
};

Let's replace the return. Copy and paste this over the file contents:

<?php

declare(strict_types=1);

namespace App\Foo;

interface Bar {
    public function __invoke();
}

return fn() => 'Baz!!!';

Important! Returning a string from our service allows app/console to output the service's response directly to the command line, in JSON format.

Now in a shell, run the following command:

./play foo/bar

You should receive your function's response in the console output.

$ ./play foo/bar
Baz!!!

You have now written your first Pure Expressive-style application!