The base-feature-macros package
This provides a set of feature macros describing features of
base in a semantic way.
See <base-feature-macros.h> for the set of currently provided macros.
In order to use the CPP header provided by this package, add this package as a dependency to your
.cabal file, i.e.
build-depends: base-feature-macros: >= 0.1 && < 0.2
while making sure that the version specified as lower bound defines the feature-macros your code tests for. This is particularly important as CPP will implicitly treat undefined CPP macros as having the value
0. See also GNU CPP/CC's
-Wundef warning to detect such errors;
or starting with GHC 8.2, -Wcpp-undef can be used:
if impl(ghc >= 8.2) ghc-options: -Wcpp-undef
Then in your code, you can include and use the
<base-feature-macros.h> header like so
module M where #include <base-feature-macros.h> #if !HAVE_FOLDABLE_TRAVERSABLE_IN_PRELUDE import Data.Foldable (Foldable (..)) import Prelude hiding (foldr, foldr1) #endif #if !HAVE_MONOID_IN_PRELUDE import Data.Monoid hiding ((<>)) #endif
This package is inspired by the blogpost "Make macros mean something – readable backwards compatibility with CPP".
|Dependencies||base (>=4.3 && <4.11) [details]|
|Author||Herbert Valerio Riedel|
|Source repo||head: git clone https://github.com/hvr/base-feature-macros.git|
|Uploaded||Mon Jun 5 22:09:36 UTC 2017 by HerbertValerioRiedel|
|Downloads||539 total (20 in the last 30 days)|
|Rating||(no votes yet) [estimated by rule of succession]|
|Status||Docs not available [build log]
Last success reported on 2017-06-05 [all 2 reports]
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