proxied: Make functions consume Proxy instead of undefined
proxied
is a simple library that exports a function to
convert constant functions to ones that take a proxy
value in the Data.Proxied module. This is useful for
retrofiting typeclasses that have functions that return a
constant value for any value of a particular type (but
still need to consume some value, since one of the
parameterized types must appear in a typeclass function).
Often, these functions are given undefined
as an
argument, which might be considered poor design.
Proxy
, however, does not carry any of the
error-throwing risks of undefined
, so it is much more
preferable to take Proxy
as an argument to a constant
function instead of undefined
. Unfortunately, Proxy
wasn't included in base
until GHC 7.8, so many of base
's
typeclasses still contain constant functions that aren't
amenable to passing Proxy
. proxied
addresses this
issue by providing variants of those typeclass functions
that take an explicit proxy
value.
This library also contains the Data.Proxyless module,
which works in the opposite direction. That is, one can
take functions which take Proxy
(or undefined
) as an
argument and convert them to functions which take no
arguments. This trick relies on the -XTypeApplications
extension, so it is only available with GHC 8.0 or later.
This library also offers
Data.Proxyless.RequiredTypeArguments, a variant of
Data.Proxyless that uses -XRequiredTypeArguments
to
make type arguments explicit, which is only available with
GHC 9.10 or later.
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Downloads
- proxied-0.3.2.tar.gz [browse] (Cabal source package)
- Package description (as included in the package)
Maintainer's Corner
For package maintainers and hackage trustees
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Versions [RSS] | 0.1, 0.1.1, 0.2, 0.3, 0.3.1, 0.3.2 |
---|---|
Change log | CHANGELOG.md |
Dependencies | base (>=4.3 && <5), generic-deriving (>=1.10.1 && <2), tagged (>=0.4.4 && <1) [details] |
Tested with | ghc ==7.0.4, ghc ==7.2.2, ghc ==7.4.2, ghc ==7.6.3, ghc ==7.8.4, ghc ==7.10.3, ghc ==8.0.2, ghc ==8.2.2, ghc ==8.4.4, ghc ==8.6.5, ghc ==8.8.4, ghc ==8.10.7, ghc ==9.0.2, ghc ==9.2.8, ghc ==9.4.8, ghc ==9.6.5, ghc ==9.8.2, ghc ==9.10.1 |
License | BSD-3-Clause |
Copyright | (C) 2016-2017 Ryan Scott |
Author | Ryan Scott |
Maintainer | Ryan Scott <ryan.gl.scott@gmail.com> |
Category | Data |
Home page | https://github.com/RyanGlScott/proxied |
Bug tracker | https://github.com/RyanGlScott/proxied/issues |
Source repo | head: git clone https://github.com/RyanGlScott/proxied |
Uploaded | by ryanglscott at 2024-04-20T11:56:13Z |
Distributions | LTSHaskell:0.3.2, NixOS:0.3.2, Stackage:0.3.2 |
Reverse Dependencies | 2 direct, 0 indirect [details] |
Downloads | 4087 total (24 in the last 30 days) |
Rating | (no votes yet) [estimated by Bayesian average] |
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Status | Docs available [build log] Last success reported on 2024-04-20 [all 1 reports] |