computer programming Computer programming is the process of performing a particular computation (or more generally, accomplishing a specific computing result), usually by designing and building an executable computer program. Programming involves tasks such as anal ...

, a mirror is a

reflection Reflection or reflexion may refer to: Science and technology * Reflection (physics), a common wave phenomenon ** Specular reflection, reflection from a smooth surface *** Mirror image, a reflection in a mirror or in water ** Signal reflection, in s ...

mechanism that is completely decoupled from the object whose structure is being introspected. This is as opposed to traditional reflection, for example in

Java Java (; id, Jawa, ; jv, ꦗꦮ; su, ) is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea to the north. With a population of 151.6 million people, Java is the world's mo ...

, where one introspects an object using methods from the object itself (e.g. getClass()). Mirrors adhere to the qualities of

encapsulation Encapsulation may refer to: Chemistry * Molecular encapsulation, in chemistry, the confinement of an individual molecule within a larger molecule * Micro-encapsulation, in material science, the coating of microscopic particles with another mater ...

, stratification and ontological correspondence.

Benefits

Decoupling the reflection mechanism from the objects themselves allows for a few benefits: * The object's interface is not polluted, so there is no danger of breaking reflection by overriding a reflective method. * There can be different mirror systems. * The mirror system can be removed entirely (potentially allowing for optimizations). * A mirror system can operate on remote code, since it is not coupled with a particular machine.

Languages that use mirrors

Dart Dart or DART may refer to: * Dart, the equipment in the game of darts Arts, entertainment and media * Dart (comics), an Image Comics superhero * Dart, a character from ''G.I. Joe'' * Dart, a ''Thomas & Friends'' railway engine character * D ...

, via its ''reflect'' function. * Inko, via its ''std::mirror'' module. * Rubinius (

Ruby A ruby is a pinkish red to blood-red colored gemstone, a variety of the mineral corundum (aluminium oxide). Ruby is one of the most popular traditional jewelry gems and is very durable. Other varieties of gem-quality corundum are called sapp ...

implementation), via its ''Rubinius::Mirror.reflect'' method. * Scala *

Swift Swift or SWIFT most commonly refers to: * SWIFT, an international organization facilitating transactions between banks ** SWIFT code * Swift (programming language) * Swift (bird), a family of birds It may also refer to: Organizations * SWIFT ...

, via its ''reflect'' function.

References

Programming paradigms {{comp-sci-stub