First class patterns and pattern matching, using type families https://github.com/reinerp/first-class-patterns
|Latest on Hackage:||0.3.2.3|
This package implements a library of first class patterns. The initial basis for this library was Morten Rhiger's "Type-safe pattern combinators"; the patterns can be used in an almost identical way to those of Morten Rhiger. In a series of blog posts at http://reinerp.wordpress.com/category/pattern-combinators/ the types of patterns were made more revealing using type families, and a simpler implementation was used which avoids some book-keeping.
The library reimplements most of Haskell's built-in pattern matching facilities, plus some more. The pattern matches of this library are lightweight: when GHC's optimisation is turned on, all overhead should be optimised away, leaving a standard Haskell pattern match.
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