talks/things-to-know-php/sections/getting-started.rst

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How do I get started?

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``php -v``

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``PHP 8.1.0 (cli) (built: Nov 30 2021 07:15:23) (NTS)
Copyright (c) The PHP Group
Zend Engine v4.1.0, Copyright (c) Zend Technologies``

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``vim index.php``

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   TextAnnotation "Create a new file called 'index.php' in the text editor of your choice."

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Your first PHP file
===================

.. code-block:: php
   :linenos:

   <?php

   // index.php

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   TextAnnotation "Add an opening tag (closing tag is optional, and in some cases should not be used)."
   
Your first PHP file
===================

.. code-block:: php
   :linenos:

   <?php

   // index.php

   echo 'Hello World';

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``php index.php``

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``php -S localhost:8000``

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``/app # php -S localhost:8000``

``[Tue Mar  8 20:52:39 2022] PHP 8.1.0 Development Server
(http://localhost:8000) started``

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   TextAnnotation "PHP's local development web server. Fine for simple scripts or apps."

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.. image:: images/hello-world.png
   :width: 23cm

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``docker run --rm
-v $PWD:/app
-w /app
php:8.1-cli-alpine
php index.php``

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``docker run --rm
-v $PWD:/app
-w /app
php:7.4-cli-alpine
php index.php``

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    TextAnnotation "7.4 instead of 8.1"

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``docker run --rm
-v $PWD:/var/www/html
-p 80:80
php:8.1-apache``

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    TextAnnotation "Apache rather than CLI"

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.. code-block:: php
   :linenos:

   <?php

    // index.php

    function say()
    {
        echo 'Hello!';
    }


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    TextAnnotation "Global function."

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.. code-block:: php
   :linenos:

   <?php

    // index.php

    function say($value)
    {
        echo $value;
    }

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.. code-block:: php
   :linenos:

   <?php

    // index.php

    function say(string $value): void
    {
        echo $value;
    }

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   TextAnnotation "In PHP 7, we can declare type hints on scalar values (e.g. string). Arrays and classes were possible in previous versions."
   TextAnnotation "We can also declare a return type. In this case, there is nothing returned, so the return type is `void`."

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.. code-block:: php
   :linenos:

   <?php

    // index.php

    function say(string $value): string
    {
        return $value;
    }

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   TextAnnotation "Return a string rather than echoing a string."

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.. code-block:: php
    :linenos:

    <?php

    // src/Person.php

    class Person
    {
        public function say(string $value): void
        {
            echo $value;
        }
    }

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   TextAnnotation "Move it into a class called `Person`. Function now becomes a method, though behaves in exactly the same way."

.. page::

.. code-block:: php
   :linenos:

   <?php

   // Version 1.
   say();

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.. code-block:: php
   :linenos:

   <?php

   // Version 1.
   say();

   // Version 2.
   say('something');

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   TextAnnotation "First version with no arguments."
   TextAnnotation "Second version providing the text as an argument."
   TextAnnotation "Third version using the Person class."

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.. code-block:: php
   :linenos:

   <?php

   // Version 1.
   say();

   // Version 2.
   say('something');

   // Version 3.
   $person = new Person();
   $person->say('something');