The fclabels package

[Tags:benchmark, bsd3, library, test]

This package provides first class labels that can act as bidirectional record fields. The labels can be derived automatically using Template Haskell which means you don't have to write any boilerplate yourself. The labels are implemented as lenses and are fully composable. Labels can be used to get, set and modify parts of a datatype in a consistent way.

See Data.Label for an introductory explanation.

Internally lenses are not tied to Haskell functions directly, but are implemented as arrows. Arrows allow the lenses to be run in custom computational contexts. This approach allows us to make partial lenses that point to fields of multi-constructor datatypes in an elegant way.

See the Data.Label.Maybe module for the use of partial labels.

 1.0.1 -> 1.0.2
   - Allow generating monomorphic labels.
   - Prettify type variables in TH-derived code.


Versions 0.1, 0.1.2, 0.2.0, 0.3.0, 0.4.0, 0.4.1, 0.4.2,, 0.9.0, 0.9.1, 0.11.0, 0.11.1,, 0.11.2, 1.0, 1.0.1, 1.0.2, 1.0.3, 1.0.4, 1.0.5, 1.1.0,,,,, 1.1.2, 1.1.3, 1.1.4,,,, 1.1.5, 1.1.6, 1.1.7,, 2.0,,,,,, 2.0.1,, 2.0.2,,,,, 2.0.3,,
Dependencies base (<5), mtl (>=1.0 && <2.2), template-haskell (>=2.2 && <2.7), transformers (==0.2.*) [details]
License BSD3
Author Sebastiaan Visser, Erik Hesselink, Chris Eidhof, Sjoerd Visscher.
Maintainer Sebastiaan Visser <>
Stability Unknown
Category Data
Source repository head: git clone git://
Uploaded Wed Aug 24 16:47:27 UTC 2011 by SebastiaanVisser
Distributions Arch:, Debian:, LTSHaskell:, NixOS:, Stackage:, Tumbleweed:
Downloads 21316 total (70 in the last 30 days)
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Status Docs uploaded by user
Build status unknown [no reports yet]




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