comfort-array: Arrays where the index type is a function of the shape type

[ bsd3, data-structures, library ] [ Propose Tags ]

Arrays from the basic array package are already very powerful compared with arrays in other languages. They may have any number of dimensions, are type safe and defined in a uniform way using the Ix class with free choice of the lower bounds (0, 1, or whatever you like).

This package goes one step further: The shape and the index type are different, but the index type is a type function of the shape type. This offers much more flexibility and type safety.

Some examples are:

  • Range: Allow dynamic choice of lower and upper array bounds such as in the Arrays from the array package. You can combine it with other shapes in other dimensions. It allows you to describe the bounds of each dimension individually.

  • Shifted: Describe array bounds by start index and length. It is sometimes more natural to use these parameters. E.g. a non-negative index type like Word cannot represent -1 and thus cannot encode an empty range starting with index 0.

  • ZeroBased, OneBased: Arrays with fixed lower bound, either 0 or 1, respectively.

  • (:+:): The Append type constructor allows to respresent block arrays, e.g. block matrices.

  • Enumeration: Arrays with indices like LT, EQ, GT and dummy shape.

  • Set: Use an arbitrary ordered set as index set.

  • Triangular: A 2D array with the shape of lower or upper triangular matrix.

The lapack package defines even more fancy shapes like tall rectangular matrices, triangular matrices and banded matrices.


Automatic Flags

Use efficient Set indexing from containers>=0.5.4


Use -f <flag> to enable a flag, or -f -<flag> to disable that flag. More info


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


Versions [RSS] 0.0, 0.0.1,, 0.1, 0.1.1, 0.1.2, 0.2, 0.3, 0.3.1, 0.4, 0.4.1, 0.5, 0.5.1, (info)
Change log
Dependencies base (>=4.5 && <5), containers (>=0.4 && <0.7), deepseq (>=1.3 && <1.5), guarded-allocation (>=0.0.1 && <0.1), non-empty (>=0.3 && <0.4), primitive (>=0.6.4 && <0.8), QuickCheck (>=2 && <3), storable-record (>=0.0.1 && <0.1), transformers (>=0.3 && <0.6), utility-ht (>=0.0.10 && <0.1) [details]
License BSD-3-Clause
Author Henning Thielemann <>
Maintainer Henning Thielemann <>
Revised Revision 1 made by HenningThielemann at 2019-05-19T13:48:50Z
Category Data Structures
Home page
Source repo this: darcs get --tag 0.3.1
head: darcs get
Uploaded by HenningThielemann at 2019-02-13T08:45:39Z
Distributions LTSHaskell:, NixOS:, Stackage:
Downloads 5736 total (27 in the last 30 days)
Rating 2.0 (votes: 1) [estimated by Bayesian average]
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Status Docs available [build log]
Last success reported on 2019-02-13 [all 1 reports]