typerep-map: Efficient implementation of a dependent map with types as keys

[ data, data-structures, library, mpl, types ] [ Propose Tags ]

A dependent map from type representations to values of these types.

Here is an illustration of such a map:

    TMap
---------------
 Int  -> 5
 Bool -> True
 Char -> 'x'

In addition to TMap, we provide TypeRepMap parametrized by a vinyl-style interpretation. This data structure is equivalent to DMap TypeRep, but with significantly more efficient lookups.


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Versions [RSS] [faq] 0.1.0, 0.2.0, 0.3.0, 0.3.1, 0.3.2, 0.3.3.0, 0.4.0.0 (info)
Change log CHANGELOG.md
Dependencies base (>=4.9 && <5), containers, ghc-prim, primitive (>=0.6.4), vector [details]
License MIT
Copyright 2017-2018 Kowainik
Author Kowainik, Vladislav Zavialov
Maintainer xrom.xkov@gmail.com
Category Data, Data Structures, Types
Home page https://github.com/kowainik/typerep-map
Bug tracker https://github.com/kowainik/typerep-map/issues
Source repo head: git clone https://github.com/kowainik/typerep-map.git
Uploaded by vrom911 at 2018-07-11T03:57:21Z
Distributions LTSHaskell:0.3.3.0, NixOS:0.3.3.0, Stackage:0.4.0.0
Downloads 10778 total (785 in the last 30 days)
Rating 2.5 (votes: 3) [estimated by Bayesian average]
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Status Hackage Matrix CI
Docs available [build log]
Last success reported on 2018-07-11 [all 1 reports]

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Readme for typerep-map-0.1.0

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typerep-map

Hackage Build status MIT license

typerep-map introduces TMap and TypeRepMap — data structures like Map, but where types serve as keys, and values have the types specified in the corresponding key spots.

Usage example

ghci> import Data.TMap

ghci> tm = insert True $ one (42 :: Int)

ghci> size tm
2

ghci> res = lookup tm

ghci> res :: Maybe Int
Just 42

ghci> res :: Maybe Bool
Just True

ghci> res :: Maybe String
Nothing

ghci> lookup (insert "hello" tm) :: Maybe String
Just "hello"

ghci> member @Int tm
True

ghci> tm' = delete @Int tm

ghci> member @Int tm'
False

Benchmarks

Tables below contain comparision with DMap TypeRep of ten lookup operations on structure with size 10^4:

ghc-8.2.2 ghc-8.4.3
DMap TypeRep 517.5 ns 779.9 ns
typerep-map 205.3 ns 187.2 ns
ghc-8.2.2 ghc-8.4.3
DMap 8.2.2 DMap 8.4.3
TMap 8.2.2 TMap 8.4.3