@hackage HList0.5.4.0
Heterogeneous lists
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License
MIT
Maintainer
oleg@pobox.com
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Dependencies (9)
- array
- base >=4.7 && <4.21
- ghc-prim
- mtl
- template-haskell
- base-orphans Show all…
Dependents (25)
@hackage/Spock, @hackage/synthesizer-llvm, @hackage/functional-arrow, @hackage/ixmonad, @hackage/Rlang-QQ, @hackage/acme-everything, Show all…
Package Flags
new_type_eq
(off by default)
use Data.Type.Equality.== to define the instance of HEq instead of overlapping instances (in Data.HList.TypeEqO) (needs ghc >= 7.8)
This version does not allow `HEq x [x] f` to lead to f ~ False, unlike the version with overlapping instances. See https://ghc.haskell.org/trac/ghc/ticket/9918
HList provides many operations to create and manipulate heterogenous lists (HLists) whose length and element types are known at compile-time. HLists are used to implement
records
variants
type-indexed products (TIP)
type-indexed co-products (TIC)
keyword arguments
User code should import Data.HList or
Data.HList.CommonMain for a slightly more limited scope
The original design is described in http://okmij.org/ftp/Haskell/HList-ext.pdf,
though since that paper came out, the -XTypeFamiles extension has been used to
replace TypeCast with ~.