#12001: RFC: Add pattern synonyms to base -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: libraries/base | Version: 7.10.3 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by nomeata): I am very sceptical. Pattern synonyms are still relatively new, and I would say that best practices around them have not evolved yet (e.g.: should they be used for non-injective convenience patterns like `Popcount` at all? Should they be used for anything else but compatible or alternative views on data types?) Also, they clutter the namespace. Therefore, I would prefer if less central libraries would be first to take up pattern synonym and explore usage patterns, until it becomes apparent with which intensity pattern synonym make most sense. More concretely, of your list above, I’d give a +1 only to `Polar`. This is a genuine, self-descriptive constructor-like view on a data type. A bit fishy around 0, but that’s inherent in the general concept and not an issue with the constructor. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12001#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler