| Copyright | (c) Atze van der Ploeg 2014 |
|---|---|
| License | BSD-style |
| Maintainer | atzeus@gmail.org |
| Stability | provisional |
| Portability | portable |
| Safe Haskell | Safe-Inferred |
| Language | Haskell98 |
Data.TASequence.Class
Description
A type class for type aligned sequences: heterogeneous sequences where the types enforce the element order.
Type aligned sequences are best explained by an example: a type aligned sequence of functions is a sequence f 1 , f 2 , f 3 ... f n such that the composition of these functions f 1 ◦ f 2 ◦ f 3 ◦ ... ◦ f n is well typed. In other words: the result type of each function in the sequence must be the same as the argument type of the next function (if any). In general, the elements of a type aligned sequence do not have to be functions, i.e. values of type a → b, but can be values of type (c a b), for some binary type constructor c. Hence, we define a type aligned sequence to be a sequence of elements of the type (c a_i b_i ) with the side-condition b_i−1 = a_i . If s is the type of a type aligned sequence data structure, then (s c a b) is the type of a type aligned sequence where the first element has type (c a x), for some x, and the last element has type (c y b), for some y.
The simplest type aligned sequence data structure is a list, see Data.TASequence.ConsList. The other modules give various other type aligned sequence data structures.
See the paper Reflection without Remorse: Revealing a hidden sequence to speed up Monadic Reflection, Atze van der Ploeg and Oleg Kiselyov, Haskell Symposium 2014 for more details.
Paper: http://homepages.cwi.nl/~ploeg/zseq.pdf Talk : http://www.youtube.com/watch?v=_XoI65Rxmss
- class TASequence s where
- data TAViewL s c x y where
- data TAViewR s c x y where
Documentation
class TASequence s where Source
Minimal complete definition
Methods
tsingleton :: c x y -> s c x y Source
(><) :: s c x y -> s c y z -> s c x z infix 5 Source
Append two type aligned sequences
tviewl :: s c x y -> TAViewL s c x y Source
View the type aligned sequence from the left
tviewr :: s c x y -> TAViewR s c x y Source
View the type aligned sequence from the right
(|>) :: s c x y -> c y z -> s c x z infixl 5 Source
Append a single element to the right
(<|) :: c x y -> s c y z -> s c x z infixr 5 Source
Append a single element to the left