| Copyright | (c) 2021 Xy Ren |
|---|---|
| License | BSD3 |
| Maintainer | xy.r@outlook.com |
| Stability | unstable |
| Portability | non-portable (GHC only) |
| Safe Haskell | None |
| Language | Haskell2010 |
Cleff.Internal.Rec
Description
This module defines an immutable extensible record type, similar to vinyl and data-diverse. However this
implementation focuses on fast reads, hence has very different performance characteristics from other libraries:
- Lookup: Amortized \( O(1) \).
- Update: \( O(n) \).
- Shrink: \( O(1) \).
- Append: \( O(n) \).
This is an internal module and its API may change even between minor versions. Therefore you should be extra careful if you're to depend on this module.
Synopsis
- data Rec (f :: k -> Type) (es :: [k]) = Rec !Int !Int !(SmallArray Any)
- type family xs ++ ys where ...
- empty :: Rec f '[]
- cons :: f e -> Rec f es -> Rec f (e ': es)
- concat :: Rec f es -> Rec f es' -> Rec f (es ++ es')
- class KnownList (es :: [k])
- head :: Rec f (e ': es) -> f e
- take :: forall es es' f. KnownList es => Rec f (es ++ es') -> Rec f es
- tail :: Rec f (e ': es) -> Rec f es
- drop :: forall es es' f. KnownList es => Rec f (es ++ es') -> Rec f es'
- class Elem (e :: k) (es :: [k])
- class KnownList es => Subset (es :: [k]) (es' :: [k])
- index :: forall e es f. Elem e es => Rec f es -> f e
- pick :: forall es es' f. Subset es es' => Rec f es' -> Rec f es
- update :: forall e es f. Elem e es => f e -> Rec f es -> Rec f es
- newArr :: Int -> ST s (SmallMutableArray s Any)
Documentation
data Rec (f :: k -> Type) (es :: [k]) Source #
Extensible record type supporting efficient \( O(1) \) reads. The underlying implementation is SmallArray
slices, therefore suits small numbers of entries (i.e. less than 128).
Constructors
| Rec | |
Fields
| |
Construction
Deconstruction
class KnownList (es :: [k]) Source #
KnownList eses is concrete, i.e. is of the form '[a1, a2, ..., an] instead of a type
variable.
take :: forall es es' f. KnownList es => Rec f (es ++ es') -> Rec f es Source #
Take elements from the top of the record. \( O(m) \).
tail :: Rec f (e ': es) -> Rec f es Source #
Slice off one entry from the top of the record. \( O(1) \).
drop :: forall es es' f. KnownList es => Rec f (es ++ es') -> Rec f es' Source #
Slice off several entries from the top of the record. \( O(1) \).
Retrieval and updating
class Elem (e :: k) (es :: [k]) Source #
The element e is present in the list es.
Instances
| (TypeError (ElemNotFound e) :: Constraint) => Elem (e :: k) ('[] :: [k]) Source # | |
Defined in Cleff.Internal.Rec Methods reifyIndex :: Int | |
| Elem e es => Elem (e :: a) (e' ': es :: [a]) Source # | |
Defined in Cleff.Internal.Rec Methods reifyIndex :: Int | |
| Elem (e :: a) (e ': es :: [a]) Source # | The element closer to the head takes priority. |
Defined in Cleff.Internal.Rec Methods reifyIndex :: Int | |
class KnownList es => Subset (es :: [k]) (es' :: [k]) Source #
es is a subset of es', i.e. all elements of es are in es'.
Instances
| Subset ('[] :: [k]) (es :: [k]) Source # | |
Defined in Cleff.Internal.Rec Methods reifyIndices :: [Int] | |
| (Subset es es', Elem e es') => Subset (e ': es :: [k]) (es' :: [k]) Source # | |
Defined in Cleff.Internal.Rec Methods reifyIndices :: [Int] | |
index :: forall e es f. Elem e es => Rec f es -> f e Source #
Get an element in the record. Amortized \( O(1) \).
pick :: forall es es' f. Subset es es' => Rec f es' -> Rec f es Source #
Get a subset of the record. Amortized \( O(m) \).
update :: forall e es f. Elem e es => f e -> Rec f es -> Rec f es Source #
Update an entry in the record. \( O(n) \).
Helpers
newArr :: Int -> ST s (SmallMutableArray s Any) Source #
Create a new SmallMutableArray with no contents.