Control.Protocol.Internal

This module provides type families to combine/extract the individual states of parties as defined by command constructors intofrom the combined systemprotocol state defined as type-level list.

Documentation

type family P (partyCmd :: (party, s, s)) where ...

Extracts party from command type parameter.

Equations

P '(p, _, _) = p

type family Prj (parties :: [pk]) (state :: [k]) (party :: pk) :: k where ...

Projects the state of one party from the list of states.

Equations

Prj (p ': _) (s ': _) p = s

Prj (_ ': ps) (_ ': ss) p = Prj ps ss p

Prj '[] _ p = TypeError (NoParty p)

Prj _ '[] p = TypeError (NoParty p :$$: StateError)

type family Inj (parties :: [pk]) (state :: [k]) (p :: pk) (s' :: k) :: [k] where ...

Injects the state of some party into the party's position in the list of states.

Equations

Inj (p ': _) (_ ': ss) p s' = s' ': ss

Inj (_ ': ps) (s ': ss) p s' = s ': Inj ps ss p s'

Inj '[] _ p _ = TypeError (NoParty p)

Inj _ '[] p _ = TypeError (NoParty p :$$: StateError)

type NoParty p = (Text "Party " :<>: ShowType p) :<>: Text " is not found."

type StateError = Text "Specified fewer protocol states than parties."