PHP Code Generator
******************

.[perex]
Generate PHP code, classes, namespaces, etc. with a simple API.

Installation:

```shell
composer require nette/php-generator
```


Classes
-------

Let's start with a straightforward example of generating class using [ClassType |api:Nette\PhpGenerator\ClassType]:

```php
$class = new Nette\PhpGenerator\ClassType('Demo');

$class
	->setFinal()
	->setExtends('ParentClass')
	->addImplement('Countable')
	->addTrait('Nette\SmartObject')
	->addComment("Description of class.\nSecond line\n")
	->addComment('@property-read Nette\Forms\Form $form');

// to generate PHP code simply cast to string or use echo:
echo $class;
```

It will render this result:

```php
/**
 * Description of class.
 * Second line
 *
 * @property-read Nette\Forms\Form $form
 */
final class Demo extends ParentClass implements Countable
{
	use Nette\SmartObject;
}
```

We can add constants ([Constant |api:Nette\PhpGenerator\Constant]) and properties ([Property |api:Nette\PhpGenerator\Property]):

```php
$class->addConstant('ID', 123);

$class->addProperty('items', [1, 2, 3])
	->setVisibility('private')
	->setStatic()
	->addComment('@var int[]');
```

It generates:

```php
const ID = 123;

/** @var int[] */
private static $items = [1, 2, 3];
```

And we can add methods ([Method |api:Nette\PhpGenerator\Method]) with parameters ([Parameter |api:Nette\PhpGenerator\Parameter]):

```php
$method = $class->addMethod('count')
	->addComment('Count it.')
	->addComment('@return int')
	->setFinal()
	->setVisibility('protected')
	->setBody('return count($items ?: $this->items);');

$method->addParameter('items', []) // $items = []
		->setReference() // &$items = []
		->setTypeHint('array'); // array &$items = []
```

It results in:

```php
/**
 * Count it.
 * @return int
 */
final protected function count(array &$items = [])
{
	return count($items ?: $this->items);
}
```

If the property, constant, method or parameter already exist, it will be overwritten.

PHP Generator supports all new PHP 7.3 features:

```php
$class = new Nette\PhpGenerator\ClassType('Demo');

$class->addConstant('ID', 123)
	->setVisibility('private'); // constant visiblity

$method = $class->addMethod('getValue')
	->setReturnType('int') // method return type
	->setReturnNullable() // nullable return type
	->setBody('return count($this->items);');

$method->addParameter('id')
		->setTypeHint('int') // scalar type hint
		->setNullable(); // nullable type hint

echo $class;
```

Result:

```php
class Demo
{
	private const ID = 123;

	public function getValue(?int $id): ?int
	{
		return count($this->items);
	}
}
```


Tabs versus spaces
------------------

The generated code uses tabs for indentation, which makes it very easy to change it to any number of spaces:

```php
use Nette\PhpGenerator\Helpers;

$class = new Nette\PhpGenerator\ClassType('Demo');
// ...

echo Helpers::tabsToSpaces((string) $class); // 4 spaces indentation
echo Helpers::tabsToSpaces((string) $class, 2); // 2 spaces indentation
```


Literals
--------

You can pass any PHP code to property or parameter default values via `PhpLiteral`:

```php
use Nette\PhpGenerator\PhpLiteral;

$class = new Nette\PhpGenerator\ClassType('Demo');

$class->addProperty('foo', new PhpLiteral('Iterator::SELF_FIRST'));

$class->addMethod('bar')
	->addParameter('id', new PhpLiteral('1 + 2'));

echo $class;
```

Result:

```php
class Demo
{
	public $foo = Iterator::SELF_FIRST;

	public function bar($id = 1 + 2)
	{
	}
}
```


Interface or Trait
------------------

```php
$class = new Nette\PhpGenerator\ClassType('DemoInterface');
$class->setType('interface');
// or $class->setType('trait');
```


Trait Resolutions and Visibility
--------------------------------

```php
$class = new Nette\PhpGenerator\ClassType('Demo');
$class->addTrait('SmartObject', ['sayHello as protected']);
echo $class;
```

Result:

```php
class Demo
{
	use SmartObject {
		sayHello as protected;
	}
}
```


Anonymous Class
---------------

```php
$class = new Nette\PhpGenerator\ClassType(null);
$class->addMethod('__construct')
	->addParameter('foo');

echo '$obj = new class ($val) ' . $class . ';';
```

Result:

```php
$obj = new class ($val) {

	public function __construct($foo)
	{
	}
};
```


Global Function
---------------

Code of function will generate class [GlobalFunction |api:Nette\PhpGenerator\GlobalFunction]:

```php
$function = new Nette\PhpGenerator\GlobalFunction('foo');
$function->setBody('return $a + $b;');
$function->addParameter('a');
$function->addParameter('b');
echo $function;
```

Result:

```php
function foo($a, $b)
{
	return $a + $b;
}
```


Closure
-------

Code of closure will generate class [Closure |api:Nette\PhpGenerator\Closure]:

```php
$closure = new Nette\PhpGenerator\Closure;
$closure->setBody('return $a + $b;');
$closure->addParameter('a');
$closure->addParameter('b');
$closure->addUse('c')
	->setReference();
echo $closure;
```

Result:

```php
function ($a, $b) use (&$c) {
	return $a + $b;
}
```


Method and Function Body Generator
----------------------------------

You can use special placeholders for handy way to generate method or function body.

Simple placeholders:

```php
$str = 'any string';
$num = 3;
$function = new Nette\PhpGenerator\GlobalFunction('foo');
$function->addBody('return substr(?, ?);', [$str, $num]);
echo $function;
```

Result:

```php
function foo()
{
	return substr('any string', 3);
}
```

Variadic placeholder:

```php
$items = [1, 2, 3];
$function = new Nette\PhpGenerator\GlobalFunction('foo');
$function->setBody('myfunc(...?);', [$items]);
echo $function;
```

Result:

```php
function foo()
{
	myfunc(1, 2, 3);
}
```

Escape placeholder using slash:

```php
$num = 3;
$function = new Nette\PhpGenerator\GlobalFunction('foo');
$function->addParameter('a');
$function->addBody('return $a \? 10 : ?;', [$num]);
echo $function;
```

Result:

```php
function foo($a)
{
	return $a ? 10 : 3;
}
```


Namespace
---------

Classes, traits and interfaces (hereinafter classes) can be grouped into namespaces:

```php
$namespace = new Nette\PhpGenerator\PhpNamespace('Foo');

$class = $namespace->addClass('Task');
$interface = $namespace->addInterface('Countable');
$trait = $namespace->addTrait('NameAware');
```

If the class already exists, it will be overwritten.

You can define use-statements:

```php
$namespace->addUse('Http\Request'); // use Http\Request;
$namespace->addUse('Http\Request', 'HttpReq'); // use Http\Request as HttpReq;
```

**IMPORTANT NOTE:** when the class is part of the namespace, it is rendered slightly differently: all types (ie. type hints, return types, parent class name,
implemented interfaces and used traits) are automatically *resolved*. It means that you have to **use full class names** in definitions
and they will be replaced with aliases (according to the use-statements) or fully qualified names in the resulting code:

```php
$namespace = new Nette\PhpGenerator\PhpNamespace('Foo');
$namespace->addUse('Bar\AliasedClass');

$class = $namespace->addClass('Demo');
$class->addImplement('Foo\A') // it will resolve to A
	->addTrait('Bar\AliasedClass'); // it will resolve to AliasedClass

$method = $class->addMethod('method');
$method->addComment('@return ' . $namespace->unresolveName('Foo\D')); // in comments resolve manually
$method->addParameter('arg')
	->setTypeHint('Bar\OtherClass'); // it will resolve to \Bar\OtherClass

echo $namespace;
```

Result:

```php
namespace Foo;

use Bar\AliasedClass;

class Demo implements A
{
	use AliasedClass;

	/**
	 * @return D
	 */
	public function method(\Bar\OtherClass $arg)
	{
	}
}
```


PHP Files
---------

PHP files can contains multiple classes, namespaces and comments:

```php
$file = new Nette\PhpGenerator\PhpFile;
$file->addComment('This file is auto-generated.');

$namespace = $file->addNamespace('Foo');
$class = $namespace->addClass('A');
$class->addMethod('hello');

echo $file;
```

Result:

```php
<?php

/**
 * This file is auto-generated.
 */

namespace Foo;

class A
{
	public function hello()
	{
	}
}
```


Generate using Reflection
-------------------------

Another common use case is to create class or function based on existing ones:

```php
$class = Nette\PhpGenerator\ClassType::from(PDO::class);

$function = Nette\PhpGenerator\GlobalFunction::from('trim');

$closure = Nette\PhpGenerator\Closure::from(
	function (stdClass $a, $b = null) {}
);
```
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