| Safe Haskell | Safe |
|---|---|
| Language | Haskell2010 |
Copilot.Language.Operators.Struct
Contents
Description
Combinators to deal with streams carrying structs.
We support two kinds of operations on structs: reading the fields of structs and modifying the fields of structs.
To obtain the values of field x of a struct s, you can just write:
expr = s # x
If you want to update it, use instead a double hash to refer to the field. You can either update the field:
expr = s ## x =: 75
To update it by applying a function to it, for example, the function that updates a stream by one unit, just do:
expr = s ## x =$ (+1)
Synopsis
- class Projectable d s t | d s -> t where
- data Projection d s t
- (=:) :: Projection d s t -> Stream t -> Stream d
- (=$) :: Projection d s t -> (Stream t -> Stream t) -> Stream d
- (#) :: (KnownSymbol f, Typed t, Typed s, Struct s) => Stream s -> (s -> Field f t) -> Stream t
- (##) :: (KnownSymbol f, Typed t, Typed s, Struct s) => Stream s -> (s -> Field f t) -> Projection s (s -> Field f t) t
Documentation
class Projectable d s t | d s -> t where Source #
Common interface to manipulate portions of a larger data structure.
A projectable d s t means that it is possible to manipulate a sub-element s of type t carried in a stream of type d.
Methods
(=:) :: Projection d s t -> Stream t -> Stream d infixl 8 Source #
Modify the value of a sub-element of a type in a stream of elements of that type.
(=$) :: Projection d s t -> (Stream t -> Stream t) -> Stream d infixl 8 Source #
Update the value of a sub-element of a type in a stream of elements of that type, by applying a function on streams.
Instances
| (KnownSymbol f, Typed s, Typed t, Struct s) => Projectable s (s -> Field f t) t Source # | Update a stream of structs. |
Defined in Copilot.Language.Operators.Struct Associated Types data Projection s (s -> Field f t) t Source # | |
| (KnownNat n, Typed t) => Projectable (Array n t) (Stream Word32) t Source # | Update a stream of arrays. |
Defined in Copilot.Language.Operators.Array | |
(#) :: (KnownSymbol f, Typed t, Typed s, Struct s) => Stream s -> (s -> Field f t) -> Stream t Source #
Create a stream that carries a field of a struct in another stream.
This function implements a projection of a field of a struct over time. For
example, if a struct of type T has two fields, t1 of type Int and t2
of type Word8, and s is a stream of type Stream T, then s # t2 has
type Stream Word8 and contains the values of the t2 field of the structs
in s at any point in time.
(##) :: (KnownSymbol f, Typed t, Typed s, Struct s) => Stream s -> (s -> Field f t) -> Projection s (s -> Field f t) t Source #
Pair a stream with a field accessor, without applying it to obtain the value of the field.
This function is needed to refer to a field accessor when the goal is to update the field value, not just to read it.
Orphan instances
| (KnownSymbol f, Typed s, Typed t, Struct s) => Projectable s (s -> Field f t) t Source # | Update a stream of structs. |