Scope of Change

The XP Compiler will be extended to support compile-time metaprogramming

Rationale

Build libraries like xp-forge/partial into compiler.

Functionality

<<value>>
class Person {
  private int $id;
  private string $name;
}

The compiler finds an implementation which was previously registered via Transformations::register() for class nodes. The function gets executed and transforms the above to the following PHP:

class Person implements \lang\Value {
  private $id;
  private $name;

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

  public function id() { return $this->id; }

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

  // toString(), hashCode() and compareTo() omitted for brevity
}

Security considerations

Speed impact

Dependencies

xp-framework/compiler#19

Related documents

https://dzone.com/articles/compile-time-metaprogramming
http://groovy-lang.org/metaprogramming.html#_available_ast_transformations
http://groovy-lang.org/metaprogramming.html#developing-ast-xforms
http://notatube.blogspot.de/2010/12/project-lombok-creating-custom.html
xp-framework/compiler#15
https://wiki.php.net/rfc/parser-extension-api
microsoft/TypeScript#5595