Safe Haskell	Safe-Inferred
Language	GHC2021

SupplyChain.Vendor

Contents

Type
Connection
Some simple vendors
Running
Alteration

Description

A vendor responds to requests, makes requests, and performs actions

Synopsis

newtype Vendor (up :: Type -> Type) (down :: Type -> Type) (action :: Type -> Type) = Vendor {
- handle :: forall product. down product -> Job up action (Referral up down action product)
}
(>->) :: Vendor up middle action -> Vendor middle down action -> Vendor up down action
id :: Vendor i i action
function :: (forall response. down response -> response) -> Vendor up down action
action :: (forall response. down response -> action response) -> Vendor up down action
map :: (forall x. down x -> up x) -> Vendor up down action
absurd :: Vendor up (Const Void) action
run :: Monad action => Vendor (Const Void) down action -> down product -> action (Referral (Const Void) down action product)
eval :: Vendor (Const Void) down (Const Void) -> down product -> Referral (Const Void) down (Const Void) product
eval' :: Vendor (Const Void) down (Const Void) -> down product -> product
alter :: (forall x. Effect up action x -> Job up' action' x) -> Vendor up down action -> Vendor up' down action'
alter' :: (forall x. Effect up action x -> Effect up' action' x) -> Vendor up down action -> Vendor up' down action'

Type

newtype Vendor (up :: Type -> Type) (down :: Type -> Type) (action :: Type -> Type) #

Makes requests, responds to requests, and performs actions

Constructors

Vendor
Fields handle :: forall product. down product -> Job up action (Referral up down action product)

Connection

(>->) Source #

Arguments

:: Vendor up middle action	Upstream
-> Vendor middle down action	Downstream
-> Vendor up down action

Connect two vendors; the first interprets requests made by the second

id :: Vendor i i action Source #

The identity for (>->); does nothing at all

Some simple vendors

function :: (forall response. down response -> response) -> Vendor up down action Source #

A simple stateless vendor that responds to each request by applying a pure function

action :: (forall response. down response -> action response) -> Vendor up down action Source #

A simple stateless vendor that responds to each request by applying an effectful function

map :: (forall x. down x -> up x) -> Vendor up down action Source #

A vendor that applies a transformation to each request and then simply forwards it upstream.

absurd :: Vendor up (Const Void) action Source #

Vendor that never responds to any requests

Running

run Source #

Arguments

:: Monad action
=> Vendor (Const Void) down action	Vendor
-> down product	Request
-> action (Referral (Const Void) down action product)

Run a vendor in its action context

The vendor must not make requests, so its upstream interface is Const Void.

eval Source #

Arguments

:: Vendor (Const Void) down (Const Void)	Vendor
-> down product	Request
-> Referral (Const Void) down (Const Void) product

Evaluate a vendor with no context

The vendor must evokes neither request nor actions, so both its upstream and action contexts are Const Void.

eval' Source #

Arguments

:: Vendor (Const Void) down (Const Void)	Vendor
-> down product	Request
-> product

Evaluate a vendor with no context

The vendor must evokes neither request nor actions, so both its upstream and action contexts are Const Void.

Alteration

alter Source #

Arguments

:: (forall x. Effect up action x -> Job up' action' x)	Transformation applied to each effect that the vendor evokes
-> Vendor up down action
-> Vendor up' down action'

alter' Source #

Arguments

:: (forall x. Effect up action x -> Effect up' action' x)	Transformation applied to each effect that the vendor evokes
-> Vendor up down action
-> Vendor up' down action'