sop-core-0.4.0.0: True Sums of Products

Safe HaskellNone
LanguageHaskell2010

Data.SOP.Sing

Contents

Description

Singleton types corresponding to type-level data structures.

The implementation is similar, but subtly different to that of the singletons package. See the "True Sums of Products" paper for details.

Synopsis

Singletons

data SList :: [k] -> Type where Source #

Explicit singleton list.

A singleton list can be used to reveal the structure of a type-level list argument that the function is quantified over. For every type-level list xs, there is one non-bottom value of type SList xs.

Note that these singleton lists are polymorphic in the list elements; we do not require a singleton representation for them.

Since: sop-core-0.2

Constructors

SNil :: SList '[] 
SCons :: SListI xs => SList (x ': xs) 
Instances
Eq (SList xs) Source # 
Instance details

Defined in Data.SOP.Sing

Methods

(==) :: SList xs -> SList xs -> Bool #

(/=) :: SList xs -> SList xs -> Bool #

Ord (SList xs) Source # 
Instance details

Defined in Data.SOP.Sing

Methods

compare :: SList xs -> SList xs -> Ordering #

(<) :: SList xs -> SList xs -> Bool #

(<=) :: SList xs -> SList xs -> Bool #

(>) :: SList xs -> SList xs -> Bool #

(>=) :: SList xs -> SList xs -> Bool #

max :: SList xs -> SList xs -> SList xs #

min :: SList xs -> SList xs -> SList xs #

Show (SList xs) Source # 
Instance details

Defined in Data.SOP.Sing

Methods

showsPrec :: Int -> SList xs -> ShowS #

show :: SList xs -> String #

showList :: [SList xs] -> ShowS #

type SListI = All Top Source #

Implicit singleton list.

A singleton list can be used to reveal the structure of a type-level list argument that the function is quantified over.

Since 0.4.0.0, this is now defined in terms of All. A singleton list provides a witness for a type-level list where the elements need not satisfy any additional constraints.

Since: sop-core-0.4.0.0

sList :: SListI xs => SList xs Source #

Get hold of an explicit singleton (that one can then pattern match on) for a type-level list

para_SList :: SListI xs => r '[] -> (forall y ys. SListI ys => r ys -> r (y ': ys)) -> r xs Source #

Paramorphism for a type-level list.

Since: sop-core-0.4.0.0

case_SList :: SListI xs => r '[] -> (forall y ys. SListI ys => r (y ': ys)) -> r xs Source #

Case distinction on a type-level list.

Since: sop-core-0.4.0.0

Shape of type-level lists

data Shape :: [k] -> Type where Source #

Occassionally it is useful to have an explicit, term-level, representation of type-level lists (esp because of https://ghc.haskell.org/trac/ghc/ticket/9108 )

Constructors

ShapeNil :: Shape '[] 
ShapeCons :: SListI xs => Shape xs -> Shape (x ': xs) 
Instances
Eq (Shape xs) Source # 
Instance details

Defined in Data.SOP.Sing

Methods

(==) :: Shape xs -> Shape xs -> Bool #

(/=) :: Shape xs -> Shape xs -> Bool #

Ord (Shape xs) Source # 
Instance details

Defined in Data.SOP.Sing

Methods

compare :: Shape xs -> Shape xs -> Ordering #

(<) :: Shape xs -> Shape xs -> Bool #

(<=) :: Shape xs -> Shape xs -> Bool #

(>) :: Shape xs -> Shape xs -> Bool #

(>=) :: Shape xs -> Shape xs -> Bool #

max :: Shape xs -> Shape xs -> Shape xs #

min :: Shape xs -> Shape xs -> Shape xs #

Show (Shape xs) Source # 
Instance details

Defined in Data.SOP.Sing

Methods

showsPrec :: Int -> Shape xs -> ShowS #

show :: Shape xs -> String #

showList :: [Shape xs] -> ShowS #

shape :: forall (xs :: [k]). SListI xs => Shape xs Source #

The shape of a type-level list.

lengthSList :: forall (xs :: [k]) proxy. SListI xs => proxy xs -> Int Source #

The length of a type-level list.

Since: sop-core-0.2