1.
AST + Better Reflection
James Titcumb
PHP Benelux 2016 Unconference

2.
James Titcumb
www.jamestitcumb.com
www.roave.com
www.phphants.co.uk
www.phpsouthcoast.co.uk
@asgrim
Who is this guy?

3.
Reflection

4.
© 1937 Disney’s Snow White - disneyscreencaps.com

5.
● Structure
● Metadata
● Values
● Type introspection
● Modification
Reflection

6.
How does it work?

7.
GET_REFLECTION_OBJECT_PTR(ce);
lc_name = zend_str_tolower_dup(name, name_len);
if ((ce == zend_ce_closure && (name_len == sizeof(ZEND_INVOKE_FUNC_NAME)-1)
&& memcmp(lc_name, ZEND_INVOKE_FUNC_NAME, sizeof(ZEND_INVOKE_FUNC_NAME)-1) == 0)
|| zend_hash_str_exists(&ce->function_table, lc_name, name_len)) {
efree(lc_name);
RETURN_TRUE;
} else {
efree(lc_name);
RETURN_FALSE;
}

8.
Okay. What now?

9.
github.com/ /BetterReflection
Better Reflection!

10.
What?

11.
Why?

12.
How?

13.
Magic of the AST

14.
source: http://goo.gl/HORwLQ

15.
WTF is AST?

16.
use PhpParserParserFactory;
$parser = (new ParserFactory)
->create(ParserFactory::PREFER_PHP7);
print_r($parser->parse(
file_get_contents('ast-demo-src.php')
));

17.
<?php
echo "Hello world";

18.
AST
`-- Echo statement
`-- String, value "Hello world"

19.
<?php
echo "Hello " . "world";

20.
AST
`-- Echo statement
`-- Concat
|-- Left
| `-- String, value "Hello "
`-- Right
`-- String, value "world"

21.
AST to Reflection

22.
Benefits?

23.
ReflectionProperty->getDocBlockTypes()
Types!

24.
Using Better Reflection

25.
$reflection = new ReflectionClass(
'BetterReflectionTestFixtureExampleClass'
);
$this->assertSame(
'ExampleClass',
$reflection->getShortName()
);

26.
$reflection = ReflectionClass::createFromName(
'BetterReflectionTestFixtureExampleClass'
);
$this->assertSame(
'ExampleClass',
$reflection->getShortName()
);

27.
// In ReflectionClass :
public static function createFromName($className)
{
return ClassReflector::buildDefaultReflector()->reflect($className);
}
// In ClassReflector :
public static function buildDefaultReflector()
{
return new self(new AggregateSourceLocator([
new PhpInternalSourceLocator(),
new EvaledCodeSourceLocator(),
new AutoloadSourceLocator(),
]));
}

28.
AutoloadSourceLocator
ReflectionClass::createFromName(new MyClass)
replace stream wrapper
disable error handling
call “class_exists”
restore stream wrapper
restore error handling
store attempted filename load
DO NOT LOAD FILE!
return stored filename
Read file and parse AST!

29.
(don’t try this at home kids!)
Some voodoo...

30.
class MyClass
{
public function foo()
{
return 5;
}
}

31.
// Create the reflection first
// ***BEFORE*** class is loaded
$classInfo = ReflectionClass::createFromName('MyClass');

32.
// Override the body...!
$methodInfo = $classInfo->getMethod('foo');
$methodInfo->setBody(function () {
return 4;
});

33.
// Save the class and require it
$classCode = (new CodePrinter())->prettyPrint([$classInfo->getAst()]);
$tmpFile = tempnam(sys_get_temp_dir(), 'br-monkey-patching');
file_put_contents($tmpFile, '<?php ' . $classCode);
require_once($tmpFile);
unlink($tmpFile);

34.
// Now create an instance, and call the function...
$c = new MyClass();
var_dump($c->foo()); // will be 4!!!

35.
What’s in it for me?

36.
The future...

37.
● DONE Currently: rewriting the internals
○ SourceLocators “might” return some code ?!
● DONE Returning AST/Code for method/fn
Ideas/plans - DONE

38.
● WIP More compatibility core reflection
● WIP Reflect core fns with default params
○ This is not currently possible with core reflection
● WIP Modification & exporting
● WIP Reflecting on closures
Ideas/plans - WIP

39.
● Adding a getColumn() function
● PHP 7 compatibility
● @inheritDoc traversal (to inherit type hints)
● Make it faster
Ideas/plans

40.
¯_(ツ)_/¯

41.
github.com/ /BetterReflection
Better Reflection

42.
Any questions? :)
https://joind.in/talk/9a5d8
James Titcumb @asgrim