System.TmpProc.TypeLevel

Defines type-level data structures and combinators used by System.TmpProc.Docker and System.TmpProc.Warp.

HList implements a heterogenous list used to define types that represent multiple concurrent tmp procs.

KV is intended for internal use within the tmp-proc package. It allows indexing and sorting of lists of tmp procs.

Heterogenous List

data HList :: [Type] -> Type where

Defines a Heterogenous list.

Constructors

HNil :: HList '[]

HCons :: anyTy -> HList manyTys -> HList (anyTy ': manyTys) infixr 5

Instances

(Show x, Show (HList xs)) => Show (HList (x ': xs))

Defined in System.TmpProc.TypeLevel

Methods

showsPrec :: Int -> HList (x ': xs) -> ShowS

show :: HList (x ': xs) -> String

showList :: [HList (x ': xs)] -> ShowS

Show (HList ('[] :: [Type]))

Defined in System.TmpProc.TypeLevel

Methods

showsPrec :: Int -> HList '[] -> ShowS

show :: HList '[] -> String

showList :: [HList '[]] -> ShowS

(Eq x, Eq (HList xs)) => Eq (HList (x ': xs))

Defined in System.TmpProc.TypeLevel

Methods

(==) :: HList (x ': xs) -> HList (x ': xs) -> Bool

(/=) :: HList (x ': xs) -> HList (x ': xs) -> Bool

Eq (HList ('[] :: [Type]))

Defined in System.TmpProc.TypeLevel

Methods

(==) :: HList '[] -> HList '[] -> Bool

(/=) :: HList '[] -> HList '[] -> Bool

(&:) :: x -> HList xs -> HList (x ': xs) infixr 5

An infix alias for HCons.

only :: x -> HList '[x]

Construct a singleton HList

(&:&) :: x -> y -> HList '[x, y] infixr 6

An infix alias for both.

both :: x -> y -> HList '[x, y] infixr 6

Construct a two-item HList.

hHead :: HList (a ': as) -> a

Obtain the first element of a HList.

hOf :: forall y xs. IsInProof y xs => Proxy y -> HList xs -> y

Get an item in an HList given its type.

class ReorderH xs ys where

Allows reordering of similar HLists.

Examples

>>> hReorder @_ @'[Bool, Int] ('c' &: (3 :: Int) &: True &: (3.1 :: Double) &: HNil)
True &: 3 &: HNil

>>> hReorder @_ @'[Double, Bool, Int] ('c' &: (3 :: Int) &: True &: (3.1 :: Double) &: HNil)
3.1 &: True &: 3 &: HNil

Methods

hReorder :: HList xs -> HList ys

Instances

ReorderH xs ('[] :: [Type])

Defined in System.TmpProc.TypeLevel

Methods

hReorder :: HList xs -> HList '[]

(IsInProof y xs, ReorderH xs ys) => ReorderH xs (y ': ys)

Defined in System.TmpProc.TypeLevel

Methods

hReorder :: HList xs -> HList (y ': ys)

A type-level Key-Value

data KV :: Symbol -> Type -> Type where

Use a type-level symbol as key type that indexes a value type.

Constructors

V :: a -> KV s a

Instances

ManyMemberKV ks ts kvs => ManyMemberKV ks ts (KV ok ot ': kvs)

Defined in System.TmpProc.TypeLevel

Methods

manyProof :: LookupMany ks ts (KV ok ot ': kvs)

MemberKV k t '[KV k t]

Defined in System.TmpProc.TypeLevel

Methods

lookupProof :: LookupKV k t '[KV k t]

MemberKV k t (KV k t ': kvs)

Defined in System.TmpProc.TypeLevel

Methods

lookupProof :: LookupKV k t (KV k t ': kvs)

MemberKV k t kvs => MemberKV k t (KV ok ot ': kvs)

Defined in System.TmpProc.TypeLevel

Methods

lookupProof :: LookupKV k t (KV ok ot ': kvs)

ManyMemberKV '[k] '[t] (KV k t ': ks)

Defined in System.TmpProc.TypeLevel

Methods

manyProof :: LookupMany '[k] '[t] (KV k t ': ks)

ManyMemberKV ks ts kvs => ManyMemberKV (k ': ks) (t ': ts) (KV k t ': kvs)

Defined in System.TmpProc.TypeLevel

Methods

manyProof :: LookupMany (k ': ks) (t ': ts) (KV k t ': kvs)

select :: forall k t xs. MemberKV k t xs => HList xs -> t

Select an item from an HList of KVs by key.

N.B Returns the first item. It assumes the keys in the KV HList are unique. TODO: enforce this rule using a constraint.

Examples

>>> select @"d" @Double  @'[KV "b" Bool, KV "d" Double] (V True &:  V (3.1 :: Double) &: HNil)
3.1

selectMany :: forall ks ts xs. ManyMemberKV ks ts xs => HList xs -> HList ts

Select items with specified keys from an HList of KVs by key.

N.B. this this is an internal function.

The keys must be provided in the same order as they occur in the HList, any other order will likely result in an compiler error.

Examples

>>> selectMany @'["b"] @'[Bool] @'[KV "b" Bool, KV "d" Double] (V True &:  V (3.1 :: Double) &: HNil)
True &: HNil

data LookupKV (k :: Symbol) t (xs :: [Type]) where

Proves a symbol and its type occur as entry in a list of KV types.

Constructors

AtHead :: LookupKV k t (KV k t ': kvs)

OtherKeys :: LookupKV k t kvs -> LookupKV k t (KV ok ot ': kvs)

class MemberKV (k :: Symbol) (t :: Type) (xs :: [Type]) where

Generate proof instances of LookupKV.

Methods

lookupProof :: LookupKV k t xs

Instances

MemberKV k t '[KV k t]

Defined in System.TmpProc.TypeLevel

Methods

lookupProof :: LookupKV k t '[KV k t]

MemberKV k t (KV k t ': kvs)

Defined in System.TmpProc.TypeLevel

Methods

lookupProof :: LookupKV k t (KV k t ': kvs)

MemberKV k t kvs => MemberKV k t (KV ok ot ': kvs)

Defined in System.TmpProc.TypeLevel

Methods

lookupProof :: LookupKV k t (KV ok ot ': kvs)

class ManyMemberKV (ks :: [Symbol]) (ts :: [Type]) (kvs :: [Type]) where

Generate proof instances of LookupMany.

Methods

manyProof :: LookupMany ks ts kvs

Instances

ManyMemberKV ks ts kvs => ManyMemberKV ks ts (KV ok ot ': kvs)

Defined in System.TmpProc.TypeLevel

Methods

manyProof :: LookupMany ks ts (KV ok ot ': kvs)

ManyMemberKV '[k] '[t] (KV k t ': ks)

Defined in System.TmpProc.TypeLevel

Methods

manyProof :: LookupMany '[k] '[t] (KV k t ': ks)

ManyMemberKV ks ts kvs => ManyMemberKV (k ': ks) (t ': ts) (KV k t ': kvs)

Defined in System.TmpProc.TypeLevel

Methods

manyProof :: LookupMany (k ': ks) (t ': ts) (KV k t ': kvs)

Other combinators

type family IsAbsent e r :: Constraint where ...

A constraint that confirms that a type is not present in a type-level list.

Equations

IsAbsent e '[] = ()

IsAbsent e (e ': _) = TypeError (NotAbsentErr e)

IsAbsent e (e' ': tail) = IsAbsent e tail

class IsInProof t (tys :: [Type])

Generate proof instances of IsIn.

Minimal complete definition

provedIsIn

Instances

IsInProof t tys => IsInProof t (a ': tys)

Defined in System.TmpProc.TypeLevel

Methods

provedIsIn :: IsIn t (a ': tys)

IsInProof t (t ': tys)

Defined in System.TmpProc.TypeLevel

Methods

provedIsIn :: IsIn t (t ': tys)

Re-exports

module System.TmpProc.TypeLevel.Sort