syb: Scrap Your Boilerplate

[ bsd3, generics, library ] [ Propose Tags ]
Versions,,,, 0.2, 0.2.1, 0.2.2, 0.3, 0.3.1, 0.3.2, 0.3.3, 0.3.4, 0.3.5, 0.3.6,,, 0.3.7, 0.4.0, 0.4.1, 0.4.2, 0.4.3, 0.4.4, 0.5, 0.5.1, 0.6, 0.7
Dependencies base (>=4.0 && <4.10) [details]
License BSD-3-Clause
Author Ralf Lammel, Simon Peyton Jones, Jose Pedro Magalhaes
Revised Revision 1 made by HerbertValerioRiedel at Mon May 22 11:40:38 UTC 2017
Category Generics
Home page
Bug tracker
Source repo head: git clone
Uploaded by JosePedroMagalhaes at Sun Jun 8 23:07:32 UTC 2014
Distributions Arch:0.7, Debian:0.6, Fedora:0.7, FreeBSD:0.5.1, LTSHaskell:0.7, NixOS:0.7, Stackage:0.7, openSUSE:0.7
Downloads 274712 total (405 in the last 30 days)
Rating (no votes yet) [estimated by rule of succession]
Your Rating
  • λ
  • λ
  • λ
Status Docs available [build log]
Successful builds reported [all 1 reports]
Hackage Matrix CI

This package contains the generics system described in the Scrap Your Boilerplate papers (see It defines the Data class of types permitting folding and unfolding of constructor applications, instances of this class for primitive types, and a variety of traversals.

[Skip to Readme]




Note: This package has metadata revisions in the cabal description newer than included in the tarball. To unpack the package including the revisions, use 'cabal get'.

Maintainer's Corner

For package maintainers and hackage trustees

Readme for syb-0.4.2

[back to package description]
syb: Scrap Your Boilerplate!

Scrap Your Boilerplate (SYB) is a library for generic programming in Haskell. It 
is supported since the GHC >= 6.0 implementation of Haskell. Using this 
approach, you can write generic functions such as traversal schemes (e.g., 
everywhere and everything), as well as generic read, generic show and generic 
equality (i.e., gread, gshow, and geq). This approach is based on just a few 
primitives for type-safe cast and processing constructor applications. 

It was originally developed by Ralf Lämmel and Simon Peyton Jones. Since then,
many people have contributed with research relating to SYB or its applications. 

More information is available on the webpage:


* Easy generic programming with combinators
* GHC can derive Data and Typeable instances for your datatypes
* Comes with many useful generic functions


* GHC 6.10.1 or later
* Cabal 1.6 or later

Bugs & Support

Please report issues or request features at the bug tracker:

For discussion about the library with the authors, maintainers, and other
interested persons use the mailing list: