The first-class-patterns package

[Tags:bsd3, library]

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 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.

If you're just reading the documentation for this library for the first time, start with Data.Pattern.


Versions 0.1.0, 0.2.0, 0.3.0, 0.3.1, 0.3.2,,,
Dependencies base (>=4.5 && <5), transformers (>=0.1.0 && <0.4) [details]
License BSD3
Author Reiner Pope, Brent Yorgey
Maintainer Brent Yorgey <>
Stability experimental
Category Data
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Source repository head: git clone git://
Uploaded Tue Jul 30 17:29:22 UTC 2013 by BrentYorgey
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Downloads 1413 total (23 in the last 30 days)
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Status Docs uploaded by user
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