Remove lang.Object class

[thekid]

Scope of Change

This RFC suggests removing the lang.Object class

Rationale

This: https://wiki.php.net/rfc/object-typehint

Functionality

The class Object in the lang package will be removed, as its declaration will cause a compile error.

Object vs. Value

Classes often extend lang.Object to:

• Inherit its default toString() method.
• Be useable inside hash contexts by inheriting its hashCode() method
• Provide (and possibly override) equals(), which is also inherited

It's easier to inherit and overwrite instead of implementing lang.Value fully.

Traits

A solution to this will be to add traits to implement lang.Value by default. Classes can then include these and overwrite whatever necessary.

<?php namespace lang;

trait StringOf {
  public function toString(): string {
    return nameof($this).'@'.Objects::stringOf(get_object_vars($this));
  }
}

trait HashOf {
  public function hashCode(): string {
    return Objects::hashOf(array_merge([get_class($this)], (array)$this));
  }
}

trait Comparison {
  public function compareTo($value): int {
    return $value instanceof self ? Objects::compare((array)$this, (array)$value) : 1;
  }
}

Security considerations

n/a

Speed impact

Not measurable

Dependencies

n/a

Related documents

xp-framework/unittest#19 - example refactoring

[thekid]

Timm@SLATE %home%\devel\xp\core [master]
$ grep -HErn "extends.+Object" src|wc -l
128

[thekid]

See https://travis-ci.org/xp-forge/web/jobs/248532308

Uncaught error: Compile error (Cannot use 'Object' as class name as it is reserved)
  at <source> [line 9 of ./vendor/xp-framework/core/src/main/php/lang/Object.class.php]
  at <main>('xp.unittest.TestRunner', 'src/test/php') [line 0 of .../class-main/php.class.php]