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Generic Functions

It's a not-so-great name for something that might be better called a "polymorphic function", an "extensible function", or maybe even a "composable function", as these are all better descriptions of what a generic function is.[1]

• http://dirtsimple.org/2004/11/generic-functions-have-landed.html --Generic Functions have Landed
• The "Visitor Pattern", Revisited

In certain systems for object-oriented programming such as the Common Lisp Object System and Dylan, a generic function is an entity made up of all methods having the same name.

Generic functions correspond roughly to what Smalltalk calls messages; but when a generic function is called, method dispatch occurs on the basis of all arguments, not just a single privileged one. See under multiple dispatch for more. This is also known as a multimethod.[2]

• [Python-3000] Generic functions
  • [3]
• PEP 3124: Overloading, Generic Functions, Interfaces, and Adaptation
  • PEAK-rules
    
  
  
• Generic Functions: sometimes it's just point of view
  • Like Acid for Frameworks
    
  
  
• http://danielnouri.org/blog/devel/adaptation-and-generic-functions.html

• Generic functions vs mixins: a case study

Alternatively, I could use Dependency Injection and pass to the constructor all of its loggers, but this is also undesiderable, since I would be complicating the signature always, even if I needed to use a non-standard logger only very few times. I could use different factories to instantiate the class with different loggers, of course, but I think that the generic function approach is a much better solution. It clearly decouples the logging capabilities from the other features of the framework class, which stays simple. Client code does not need to touch the framework class, they just register their preferred logging function and it is done. Moreover generic functions are not just for logging: they are a general mechanism that you can use in many other circumstances.

• Introducing Generic Functions(clip)

Predicate Dispatch

Predicate-based dispatching goes considerably further, allowing real duck typing, e.g., you could implement a pformat method for everything that has an "__iter__" method and no "next" method (i.e., all iterables, but not iterators which could lead to unintentionally consuming the iterator).[4]

• Predicate Dispatch
• Predicate Dispatching in the Common Lisp Object System
  
• Charming Python: Scaling a new PEAK

• First Try at Generic Functions
  • easy_install -Zf http://peak.telecommunity.com/snapshots/ RuleDispatch
• Torture-testing Generic Function Performance

Adaptation

• Component Adaptation + Open Protocols = The PyProtocols Package
  
• Python 3000 - Adaptation or Generic Functions?
  • killed: PEP 246 (adaptation) and PEP 245 (interfaces)
  • GenericFunctions as Adaptation: a GF-factory that returns the adapted object

in Python

• http://cheeseshop.python.org/pypi/simplegeneric/