Functor hierarchy proposal and class system extension proposal

Howard B. Golden hgolden at socal.rr.com
Mon Dec 27 23:35:53 CET 2010


Hi,

In 2006, Ashley Yakeley proposed the functor hierarchy proposal 
(http://www.haskell.org/haskellwiki/Functor_hierarchy_proposal), and, in 
2007, Brianh (his wiki handle since I don't know his name) proposed the 
class system extension proposal 
(http://www.haskell.org/haskellwiki/Class_system_extension_proposal).

I recently Googled these proposals and didn't see any significant 
discussion since they were originally proposed. If there has been some, 
please point me to it so I can read it.

Making functor a superclass of monad has the benefit of consistency with 
the mathematical definitions. It may also simplify the libraries. The 
class system extension proposal makes it possible to inherit the default 
implementations of functions from a superclass, thus simplifying the 
code that would otherwise be required to create a monad if the functor 
hierarchy proposal is adopted.

Is there any interest in considering these proposals for the next 
iteration of Haskell'?

Cheers,

Howard B. Golden
Northridge, California, USA



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