Safe Haskell	None
Language	Haskell2010

Generics.SOP.Classes

Contents

Generalized applicative functor structure
Collapsing homogeneous structures
Sequencing effects
- Derived functions
Indexing into sums
Applying all injections
Expanding sums to products
Transformation of index lists and coercions

Description

Classes for generalized combinators on SOP types.

In the SOP approach to generic programming, we're predominantly concerned with four structured datatypes:

  NP  :: (k -> *) -> ( [k]  -> *)   -- n-ary product
  NS  :: (k -> *) -> ( [k]  -> *)   -- n-ary sum
  POP :: (k -> *) -> ([[k]] -> *)   -- product of products
  SOP :: (k -> *) -> ([[k]] -> *)   -- sum of products

All of these have a kind that fits the following pattern:

  (k -> *) -> (l -> *)

These four types support similar interfaces. In order to allow reusing the same combinator names for all of these types, we define various classes in this module that allow the necessary generalization.

The classes typically lift concepts that exist for kinds * or * -> * to datatypes of kind (k -> *) -> (l -> *). This module also derives a number of derived combinators.

The actual instances are defined in Generics.SOP.NP and Generics.SOP.NS.

Synopsis

class HPure h where
newtype (f -.-> g) a = Fn {
- apFn :: f a -> g a
}
fn :: (f a -> f' a) -> (f -.-> f') a
fn_2 :: (f a -> f' a -> f'' a) -> (f -.-> (f' -.-> f'')) a
fn_3 :: (f a -> f' a -> f'' a -> f''' a) -> (f -.-> (f' -.-> (f'' -.-> f'''))) a
fn_4 :: (f a -> f' a -> f'' a -> f''' a -> f'''' a) -> (f -.-> (f' -.-> (f'' -.-> (f''' -.-> f'''')))) a
type family Same (h :: (k1 -> *) -> l1 -> *) :: (k2 -> *) -> l2 -> *
type family Prod (h :: (k -> *) -> l -> *) :: (k -> *) -> l -> *
class (Prod (Prod h) ~ Prod h, HPure (Prod h)) => HAp h where
hliftA :: (SListIN (Prod h) xs, HAp h) => (forall a. f a -> f' a) -> h f xs -> h f' xs
hliftA2 :: (SListIN (Prod h) xs, HAp h, HAp (Prod h)) => (forall a. f a -> f' a -> f'' a) -> Prod h f xs -> h f' xs -> h f'' xs
hliftA3 :: (SListIN (Prod h) xs, HAp h, HAp (Prod h)) => (forall a. f a -> f' a -> f'' a -> f''' a) -> Prod h f xs -> Prod h f' xs -> h f'' xs -> h f''' xs
hmap :: (SListIN (Prod h) xs, HAp h) => (forall a. f a -> f' a) -> h f xs -> h f' xs
hzipWith :: (SListIN (Prod h) xs, HAp h, HAp (Prod h)) => (forall a. f a -> f' a -> f'' a) -> Prod h f xs -> h f' xs -> h f'' xs
hzipWith3 :: (SListIN (Prod h) xs, HAp h, HAp (Prod h)) => (forall a. f a -> f' a -> f'' a -> f''' a) -> Prod h f xs -> Prod h f' xs -> h f'' xs -> h f''' xs
hcliftA :: (AllN (Prod h) c xs, HAp h) => proxy c -> (forall a. c a => f a -> f' a) -> h f xs -> h f' xs
hcliftA2 :: (AllN (Prod h) c xs, HAp h, HAp (Prod h)) => proxy c -> (forall a. c a => f a -> f' a -> f'' a) -> Prod h f xs -> h f' xs -> h f'' xs
hcliftA3 :: (AllN (Prod h) c xs, HAp h, HAp (Prod h)) => proxy c -> (forall a. c a => f a -> f' a -> f'' a -> f''' a) -> Prod h f xs -> Prod h f' xs -> h f'' xs -> h f''' xs
hcmap :: (AllN (Prod h) c xs, HAp h) => proxy c -> (forall a. c a => f a -> f' a) -> h f xs -> h f' xs
hczipWith :: (AllN (Prod h) c xs, HAp h, HAp (Prod h)) => proxy c -> (forall a. c a => f a -> f' a -> f'' a) -> Prod h f xs -> h f' xs -> h f'' xs
hczipWith3 :: (AllN (Prod h) c xs, HAp h, HAp (Prod h)) => proxy c -> (forall a. c a => f a -> f' a -> f'' a -> f''' a) -> Prod h f xs -> Prod h f' xs -> h f'' xs -> h f''' xs
type family CollapseTo (h :: (k -> *) -> l -> *) (x :: *) :: *
class HCollapse h where
class HAp h => HSequence h where
hsequence :: (SListIN h xs, SListIN (Prod h) xs, HSequence h) => Applicative f => h f xs -> f (h I xs)
hsequenceK :: (SListIN h xs, SListIN (Prod h) xs, Applicative f, HSequence h) => h (K (f a)) xs -> f (h (K a) xs)
class HIndex h where
type family UnProd (h :: (k -> *) -> l -> *) :: (k -> *) -> l -> *
class UnProd (Prod h) ~ h => HApInjs h where
class HExpand h where
class (Same h1 ~ h2, Same h2 ~ h1) => HTrans h1 h2 where
hfromI :: (AllZipN (Prod h1) (LiftedCoercible I f) xs ys, HTrans h1 h2) => h1 I xs -> h2 f ys
htoI :: (AllZipN (Prod h1) (LiftedCoercible f I) xs ys, HTrans h1 h2) => h1 f xs -> h2 I ys

Generalized applicative functor structure

Generalized `pure`

class HPure h where Source #

A generalization of pure or return to higher kinds.

Minimal complete definition

hpure, hcpure

Methods

hpure :: SListIN h xs => (forall a. f a) -> h f xs Source #

Corresponds to pure directly.

Instances:

hpure, pure_NP  :: SListI  xs  => (forall a. f a) -> NP  f xs
hpure, pure_POP :: SListI2 xss => (forall a. f a) -> POP f xss

hcpure :: AllN h c xs => proxy c -> (forall a. c a => f a) -> h f xs Source #

A variant of hpure that allows passing in a constrained argument.

Calling hcpure f s where s :: h f xs causes f to be applied at all the types that are contained in xs. Therefore, the constraint c has to be satisfied for all elements of xs, which is what AllMap h c xs states.

Morally, hpure is a special case of hcpure where the constraint is empty. However, it is in the nature of how AllMap is defined as well as current GHC limitations that it is tricky to prove to GHC in general that AllMap h c NoConstraint xs is always satisfied. Therefore, we typically define hpure separately and directly, and make it a member of the class.

Instances:

hcpure, cpure_NP  :: (All  c xs ) => proxy c -> (forall a. c a => f a) -> NP  f xs
hcpure, cpure_POP :: (All2 c xss) => proxy c -> (forall a. c a => f a) -> POP f xss

Instances

HPure [[k]] k (POP k) Source #
Methods hpure :: SListIN (POP k) k h xs => (forall a. f a) -> h f xs Source # hcpure :: AllN (POP k) k h c xs => proxy c -> (forall a. c a => f a) -> h f xs Source #
HPure [k] k (NP k) Source #
Methods hpure :: SListIN (NP k) k h xs => (forall a. f a) -> h f xs Source # hcpure :: AllN (NP k) k h c xs => proxy c -> (forall a. c a => f a) -> h f xs Source #

Generalized `<*>`

newtype (f -.-> g) a infixr 1 Source #

Lifted functions.

Constructors

Fn
Fields apFn :: f a -> g a

fn :: (f a -> f' a) -> (f -.-> f') a Source #

Construct a lifted function.

Same as Fn. Only available for uniformity with the higher-arity versions.

fn_2 :: (f a -> f' a -> f'' a) -> (f -.-> (f' -.-> f'')) a Source #

Construct a binary lifted function.

fn_3 :: (f a -> f' a -> f'' a -> f''' a) -> (f -.-> (f' -.-> (f'' -.-> f'''))) a Source #

Construct a ternary lifted function.

fn_4 :: (f a -> f' a -> f'' a -> f''' a -> f'''' a) -> (f -.-> (f' -.-> (f'' -.-> (f''' -.-> f'''')))) a Source #

Construct a quarternary lifted function.

type family Same (h :: (k1 -> *) -> l1 -> *) :: (k2 -> *) -> l2 -> * Source #

Maps a structure to the same structure.

Instances

type Same [[k2]] k2 [[k1]] k1 (POP k1) Source #
type Same [[k2]] k2 [[k1]] k1 (POP k1) = POP k2
type Same [[k2]] k2 [[k1]] k1 (SOP k1) Source #
type Same [[k2]] k2 [[k1]] k1 (SOP k1) = SOP k2
type Same [k2] k2 [k1] k1 (NP k1) Source #
type Same [k2] k2 [k1] k1 (NP k1) = NP k2
type Same [k2] k2 [k1] k1 (NS k1) Source #
type Same [k2] k2 [k1] k1 (NS k1) = NS k2

type family Prod (h :: (k -> *) -> l -> *) :: (k -> *) -> l -> * Source #

Maps a structure containing sums to the corresponding product structure.

Instances

type Prod [[k]] k (POP k) Source #
type Prod [[k]] k (POP k) = POP k
type Prod [[k]] k (SOP k) Source #
type Prod [[k]] k (SOP k) = POP k
type Prod [k] k (NP k) Source #
type Prod [k] k (NP k) = NP k
type Prod [k] k (NS k) Source #
type Prod [k] k (NS k) = NP k

class (Prod (Prod h) ~ Prod h, HPure (Prod h)) => HAp h where Source #

A generalization of <*>.

Minimal complete definition

hap

Methods

hap :: Prod h (f -.-> g) xs -> h f xs -> h g xs Source #

Corresponds to <*>.

For products (NP) as well as products of products (POP), the correspondence is rather direct. We combine a structure containing (lifted) functions and a compatible structure containing corresponding arguments into a compatible structure containing results.

The same combinator can also be used to combine a product structure of functions with a sum structure of arguments, which then results in another sum structure of results. The sum structure determines which part of the product structure will be used.

Instances:

hap, ap_NP  :: NP  (f -.-> g) xs  -> NP  f xs  -> NP  g xs
hap, ap_NS  :: NP  (f -.-> g) xs  -> NS  f xs  -> NS  g xs
hap, ap_POP :: POP (f -.-> g) xss -> POP f xss -> POP g xss
hap, ap_SOP :: POP (f -.-> g) xss -> SOP f xss -> SOP g xss

Instances

HAp [[k]] k (POP k) Source #
Methods hap :: Prod (POP k) k h ((k -.-> f) g) xs -> h f xs -> h g xs Source #
HAp [[k]] k (SOP k) Source #
Methods hap :: Prod (SOP k) k h ((k -.-> f) g) xs -> h f xs -> h g xs Source #
HAp [k] k (NP k) Source #
Methods hap :: Prod (NP k) k h ((k -.-> f) g) xs -> h f xs -> h g xs Source #
HAp [k] k (NS k) Source #
Methods hap :: Prod (NS k) k h ((k -.-> f) g) xs -> h f xs -> h g xs Source #

Derived functions

hliftA :: (SListIN (Prod h) xs, HAp h) => (forall a. f a -> f' a) -> h f xs -> h f' xs Source #

A generalized form of liftA, which in turn is a generalized map.

Takes a lifted function and applies it to every element of a structure while preserving its shape.

Specification:

hliftA f xs = hpure (fn f) ` hap ` xs

Instances:

hliftA, liftA_NP  :: SListI  xs  => (forall a. f a -> f' a) -> NP  f xs  -> NP  f' xs
hliftA, liftA_NS  :: SListI  xs  => (forall a. f a -> f' a) -> NS  f xs  -> NS  f' xs
hliftA, liftA_POP :: SListI2 xss => (forall a. f a -> f' a) -> POP f xss -> POP f' xss
hliftA, liftA_SOP :: SListI2 xss => (forall a. f a -> f' a) -> SOP f xss -> SOP f' xss

hliftA2 :: (SListIN (Prod h) xs, HAp h, HAp (Prod h)) => (forall a. f a -> f' a -> f'' a) -> Prod h f xs -> h f' xs -> h f'' xs Source #

A generalized form of liftA2, which in turn is a generalized zipWith.

Takes a lifted binary function and uses it to combine two structures of equal shape into a single structure.

It either takes two product structures to a product structure, or one product and one sum structure to a sum structure.

Specification:

hliftA2 f xs ys = hpure (fn_2 f) ` hap ` xs ` hap ` ys

Instances:

hliftA2, liftA2_NP  :: SListI  xs  => (forall a. f a -> f' a -> f'' a) -> NP  f xs  -> NP  f' xs  -> NP  f'' xs
hliftA2, liftA2_NS  :: SListI  xs  => (forall a. f a -> f' a -> f'' a) -> NP  f xs  -> NS  f' xs  -> NS  f'' xs
hliftA2, liftA2_POP :: SListI2 xss => (forall a. f a -> f' a -> f'' a) -> POP f xss -> POP f' xss -> POP f'' xss
hliftA2, liftA2_SOP :: SListI2 xss => (forall a. f a -> f' a -> f'' a) -> POP f xss -> SOP f' xss -> SOP f'' xss

hliftA3 :: (SListIN (Prod h) xs, HAp h, HAp (Prod h)) => (forall a. f a -> f' a -> f'' a -> f''' a) -> Prod h f xs -> Prod h f' xs -> h f'' xs -> h f''' xs Source #

A generalized form of liftA3, which in turn is a generalized zipWith3.

Takes a lifted ternary function and uses it to combine three structures of equal shape into a single structure.

It either takes three product structures to a product structure, or two product structures and one sum structure to a sum structure.

Specification:

hliftA3 f xs ys zs = hpure (fn_3 f) ` hap ` xs ` hap ` ys ` hap ` zs

Instances:

hliftA3, liftA3_NP  :: SListI  xs  => (forall a. f a -> f' a -> f'' a -> f''' a) -> NP  f xs  -> NP  f' xs  -> NP  f'' xs  -> NP  f''' xs
hliftA3, liftA3_NS  :: SListI  xs  => (forall a. f a -> f' a -> f'' a -> f''' a) -> NP  f xs  -> NP  f' xs  -> NS  f'' xs  -> NS  f''' xs
hliftA3, liftA3_POP :: SListI2 xss => (forall a. f a -> f' a -> f'' a -> f''' a) -> POP f xss -> POP f' xss -> POP f'' xss -> POP f''' xs
hliftA3, liftA3_SOP :: SListI2 xss => (forall a. f a -> f' a -> f'' a -> f''' a) -> POP f xss -> POP f' xss -> SOP f'' xss -> SOP f''' xs

hmap :: (SListIN (Prod h) xs, HAp h) => (forall a. f a -> f' a) -> h f xs -> h f' xs Source #

Another name for hliftA.

Since: 0.2

hzipWith :: (SListIN (Prod h) xs, HAp h, HAp (Prod h)) => (forall a. f a -> f' a -> f'' a) -> Prod h f xs -> h f' xs -> h f'' xs Source #

Another name for hliftA2.

Since: 0.2

hzipWith3 :: (SListIN (Prod h) xs, HAp h, HAp (Prod h)) => (forall a. f a -> f' a -> f'' a -> f''' a) -> Prod h f xs -> Prod h f' xs -> h f'' xs -> h f''' xs Source #

Another name for hliftA3.

Since: 0.2

hcliftA :: (AllN (Prod h) c xs, HAp h) => proxy c -> (forall a. c a => f a -> f' a) -> h f xs -> h f' xs Source #

Variant of hliftA that takes a constrained function.

Specification:

hcliftA p f xs = hcpure p (fn f) ` hap ` xs

hcliftA2 :: (AllN (Prod h) c xs, HAp h, HAp (Prod h)) => proxy c -> (forall a. c a => f a -> f' a -> f'' a) -> Prod h f xs -> h f' xs -> h f'' xs Source #

Variant of hcliftA2 that takes a constrained function.

Specification:

hcliftA2 p f xs ys = hcpure p (fn_2 f) ` hap ` xs ` hap ` ys

hcliftA3 :: (AllN (Prod h) c xs, HAp h, HAp (Prod h)) => proxy c -> (forall a. c a => f a -> f' a -> f'' a -> f''' a) -> Prod h f xs -> Prod h f' xs -> h f'' xs -> h f''' xs Source #

Variant of hcliftA3 that takes a constrained function.

Specification:

hcliftA3 p f xs ys zs = hcpure p (fn_3 f) ` hap ` xs ` hap ` ys ` hap ` zs

hcmap :: (AllN (Prod h) c xs, HAp h) => proxy c -> (forall a. c a => f a -> f' a) -> h f xs -> h f' xs Source #

Another name for hcliftA.

Since: 0.2

hczipWith :: (AllN (Prod h) c xs, HAp h, HAp (Prod h)) => proxy c -> (forall a. c a => f a -> f' a -> f'' a) -> Prod h f xs -> h f' xs -> h f'' xs Source #

Another name for hcliftA2.

Since: 0.2

hczipWith3 :: (AllN (Prod h) c xs, HAp h, HAp (Prod h)) => proxy c -> (forall a. c a => f a -> f' a -> f'' a -> f''' a) -> Prod h f xs -> Prod h f' xs -> h f'' xs -> h f''' xs Source #

Another name for hcliftA3.

Since: 0.2

Collapsing homogeneous structures

type family CollapseTo (h :: (k -> *) -> l -> *) (x :: *) :: * Source #

Maps products to lists, and sums to identities.

Instances

type CollapseTo [[k]] k (POP k) a Source #
type CollapseTo [[k]] k (POP k) a = [[a]]
type CollapseTo [[k]] k (SOP k) a Source #
type CollapseTo [[k]] k (SOP k) a = [a]
type CollapseTo [k] k (NP k) a Source #
type CollapseTo [k] k (NP k) a = [a]
type CollapseTo [k] k (NS k) a Source #
type CollapseTo [k] k (NS k) a = a

class HCollapse h where Source #

A class for collapsing a heterogeneous structure into a homogeneous one.

Minimal complete definition

hcollapse

Methods

hcollapse :: SListIN h xs => h (K a) xs -> CollapseTo h a Source #

Collapse a heterogeneous structure with homogeneous elements into a homogeneous structure.

If a heterogeneous structure is instantiated to the constant functor K, then it is in fact homogeneous. This function maps such a value to a simpler Haskell datatype reflecting that. An NS (K a) contains a single a, and an NP (K a) contains a list of as.

Instances:

hcollapse, collapse_NP  :: NP  (K a) xs  ->  [a]
hcollapse, collapse_NS  :: NS  (K a) xs  ->   a
hcollapse, collapse_POP :: POP (K a) xss -> [[a]]
hcollapse, collapse_SOP :: SOP (K a) xss ->  [a]

Instances

HCollapse [[k]] k (POP k) Source #
Methods hcollapse :: SListIN (POP k) k h xs => h (K k a) xs -> CollapseTo (POP k) k h a Source #
HCollapse [[k]] k (SOP k) Source #
Methods hcollapse :: SListIN (SOP k) k h xs => h (K k a) xs -> CollapseTo (SOP k) k h a Source #
HCollapse [k] k (NP k) Source #
Methods hcollapse :: SListIN (NP k) k h xs => h (K k a) xs -> CollapseTo (NP k) k h a Source #
HCollapse [k] k (NS k) Source #
Methods hcollapse :: SListIN (NS k) k h xs => h (K k a) xs -> CollapseTo (NS k) k h a Source #

Sequencing effects

class HAp h => HSequence h where Source #

A generalization of sequenceA.

Minimal complete definition

hsequence'

Methods

hsequence' :: (SListIN h xs, Applicative f) => h (f :.: g) xs -> f (h g xs) Source #

Corresponds to sequenceA.

Lifts an applicative functor out of a structure.

Instances:

hsequence', sequence'_NP  :: (SListI  xs , Applicative f) => NP  (f :.: g) xs  -> f (NP  g xs )
hsequence', sequence'_NS  :: (SListI  xs , Applicative f) => NS  (f :.: g) xs  -> f (NS  g xs )
hsequence', sequence'_POP :: (SListI2 xss, Applicative f) => POP (f :.: g) xss -> f (POP g xss)
hsequence', sequence'_SOP :: (SListI2 xss, Applicative f) => SOP (f :.: g) xss -> f (SOP g xss)

Instances

HSequence [[k]] k (POP k) Source #
Methods hsequence' :: (SListIN (POP k) k h xs, Applicative f) => h ((k :.: *) f g) xs -> f (h g xs) Source #
HSequence [[k]] k (SOP k) Source #
Methods hsequence' :: (SListIN (SOP k) k h xs, Applicative f) => h ((k :.: *) f g) xs -> f (h g xs) Source #
HSequence [k] k (NP k) Source #
Methods hsequence' :: (SListIN (NP k) k h xs, Applicative f) => h ((k :.: *) f g) xs -> f (h g xs) Source #
HSequence [k] k (NS k) Source #
Methods hsequence' :: (SListIN (NS k) k h xs, Applicative f) => h ((k :.: *) f g) xs -> f (h g xs) Source #

Derived functions

hsequence :: (SListIN h xs, SListIN (Prod h) xs, HSequence h) => Applicative f => h f xs -> f (h I xs) Source #

Special case of hsequence' where g = I.

hsequenceK :: (SListIN h xs, SListIN (Prod h) xs, Applicative f, HSequence h) => h (K (f a)) xs -> f (h (K a) xs) Source #

Special case of hsequence' where g = K a.

Indexing into sums

class HIndex h where Source #

A class for determining which choice in a sum-like structure a value represents.

Minimal complete definition

hindex

Methods

hindex :: h f xs -> Int Source #

If h is a sum-like structure representing a choice between n different options, and x is a value of type h f xs, then hindex x returns a number between 0 and n - 1 representing the index of the choice made by x.

Instances:

hindex, index_NS  :: NS  f xs -> Int
hindex, index_SOP :: SOP f xs -> Int

Examples:

>>> hindex (S (S (Z (I False))))
2
>>> hindex (Z (K ()))
0
>>> hindex (SOP (S (Z (I True :* I 'x' :* Nil))))
1

Since: 0.2.4.0

Instances

HIndex [[k]] k (SOP k) Source #
Methods hindex :: h f xs -> Int Source #
HIndex [k] k (NS k) Source #
Methods hindex :: h f xs -> Int Source #

Applying all injections

type family UnProd (h :: (k -> *) -> l -> *) :: (k -> *) -> l -> * Source #

Maps a structure containing products to the corresponding sum structure.

Since: 0.2.4.0

Instances

type UnProd [[k]] k (POP k) Source #
type UnProd [[k]] k (POP k) = SOP k
type UnProd [k] k (NP k) Source #
type UnProd [k] k (NP k) = NS k

class UnProd (Prod h) ~ h => HApInjs h where Source #

A class for applying all injections corresponding to a sum-like structure to a table containing suitable arguments.

Minimal complete definition

hapInjs

Methods

hapInjs :: SListIN h xs => Prod h f xs -> [h f xs] Source #

For a given table (product-like structure), produce a list where each element corresponds to the application of an injection function into the corresponding sum-like structure.

Instances:

hapInjs, apInjs_NP  :: SListI  xs  => NP  f xs -> [NS  f xs ]
hapInjs, apInjs_SOP :: SListI2 xss => POP f xs -> [SOP f xss]

Examples:

>>> hapInjs (I 'x' :* I True :* I 2 :* Nil)
[Z (I 'x'), S (Z (I True)), S (S (Z (I 2)))]

>>> hapInjs (POP ((I 'x' :* Nil) :* (I True :* I 2 :* Nil) :* Nil)
[SOP (Z (I 'x' :* Nil)), SOP (S (Z (I True :* (I 2 :* Nil))))]

Since: 0.2.4.0

Instances

HApInjs [[k]] k (SOP k) Source #
Methods hapInjs :: SListIN (SOP k) k h xs => Prod (SOP k) k h f xs -> [h f xs] Source #
HApInjs [k] k (NS k) Source #
Methods hapInjs :: SListIN (NS k) k h xs => Prod (NS k) k h f xs -> [h f xs] Source #

Expanding sums to products

class HExpand h where Source #

A class for expanding sum structures into corresponding product structures, filling in the slots not targeted by the sum with default values.

Since: 0.2.5.0

Minimal complete definition

hexpand, hcexpand

Methods

hexpand :: SListIN (Prod h) xs => (forall x. f x) -> h f xs -> Prod h f xs Source #

Expand a given sum structure into a corresponding product structure by placing the value contained in the sum into the corresponding position in the product, and using the given default value for all other positions.

Instances:

hexpand, expand_NS  :: SListI xs  => (forall x . f x) -> NS  f xs  -> NP  f xs
hexpand, expand_SOP :: SListI2 xss => (forall x . f x) -> SOP f xss -> POP f xss

Examples:

>>> hexpand Nothing (S (Z (Just 3))) :: NP Maybe '[Char, Int, Bool]
Nothing :* Just 3 :* Nothing :* Nil
>>> hexpand [] (SOP (S (Z ([1,2] :* "xyz" :* Nil)))) :: POP [] '[ '[Bool], '[Int, Char] ]
POP (([] :* Nil) :* ([1,2] :* "xyz" :* Nil) :* Nil)

Since: 0.2.5.0

hcexpand :: AllN (Prod h) c xs => proxy c -> (forall x. c x => f x) -> h f xs -> Prod h f xs Source #

Variant of hexpand that allows passing a constrained default.

Instances:

hcexpand, cexpand_NS  :: All  c xs  => proxy c -> (forall x . c x => f x) -> NS  f xs  -> NP  f xs
hcexpand, cexpand_SOP :: All2 c xss => proxy c -> (forall x . c x => f x) -> SOP f xss -> POP f xss

Examples:

>>> hcexpand (Proxy :: Proxy Bounded) (I minBound) (S (Z (I 20))) :: NP I '[Bool, Int, Ordering]
I False :* I 20 :* I LT :* Nil
>>> hcexpand (Proxy :: Proxy Num) (I 0) (SOP (S (Z (I 1 :* I 2 :* Nil)))) :: POP I '[ '[Double], '[Int, Int] ]
POP ((I 0.0 :* Nil) :* (I 1 :* I 2 :* Nil) :* Nil)

Since: 0.2.5.0

Instances

HExpand [[k]] k (SOP k) Source #
Methods hexpand :: SListIN (SOP k) k (Prod (SOP k) k h) xs => (forall x. f x) -> h f xs -> Prod (SOP k) k h f xs Source # hcexpand :: AllN (SOP k) k (Prod (SOP k) k h) c xs => proxy c -> (forall x. c x => f x) -> h f xs -> Prod (SOP k) k h f xs Source #
HExpand [k] k (NS k) Source #
Methods hexpand :: SListIN (NS k) k (Prod (NS k) k h) xs => (forall x. f x) -> h f xs -> Prod (NS k) k h f xs Source # hcexpand :: AllN (NS k) k (Prod (NS k) k h) c xs => proxy c -> (forall x. c x => f x) -> h f xs -> Prod (NS k) k h f xs Source #

Transformation of index lists and coercions

class (Same h1 ~ h2, Same h2 ~ h1) => HTrans h1 h2 where Source #

A class for transforming structures into related structures with a different index list, as long as the index lists have the same shape and the elements and interpretation functions are suitably related.

Since: 0.3.1.0

Minimal complete definition

htrans, hcoerce

Methods

htrans :: AllZipN (Prod h1) c xs ys => proxy c -> (forall x y. c x y => f x -> g y) -> h1 f xs -> h2 g ys Source #

Transform a structure into a related structure given a conversion function for the elements.

Since: 0.3.1.0

hcoerce :: (AllZipN (Prod h1) (LiftedCoercible f g) xs ys, HTrans h1 h2) => h1 f xs -> h2 g ys Source #

Coerce a structure into a representationally equal structure.

Examples:

>>> hcoerce (I (Just LT) :* I (Just 'x') :* I (Just True) :* Nil) :: NP Maybe '[Ordering, Char, Bool]
Just LT :* (Just 'x' :* (Just True :* Nil))
>>> hcoerce (SOP (Z (K True :* K False :* Nil))) :: SOP I '[ '[Bool, Bool], '[Bool] ]
SOP (Z (I True :* (I False :* Nil)))

Since: 0.3.1.0

Instances

HTrans [[k2]] k2 [[k1]] k1 (POP k1) (POP k2) Source #
Methods htrans :: AllZipN (POP k1) l1 (POP k2) k1 l1 k1 (Prod l1 k1 h1) c xs ys => proxy c -> (forall x y. c x y => f x -> g y) -> h1 f xs -> h2 g ys Source # hcoerce :: (AllZipN (POP k1) l1 (POP k2) k1 l1 k1 (Prod l1 k1 h1) (LiftedCoercible (POP k2) * k1 f g) xs ys, HTrans (POP k1) (POP k2) l1 k1 h1 h2) => h1 f xs -> h2 g ys Source #
HTrans [[k2]] k2 [[k1]] k1 (SOP k1) (SOP k2) Source #
Methods htrans :: AllZipN (SOP k1) l1 (SOP k2) k1 l1 k1 (Prod l1 k1 h1) c xs ys => proxy c -> (forall x y. c x y => f x -> g y) -> h1 f xs -> h2 g ys Source # hcoerce :: (AllZipN (SOP k1) l1 (SOP k2) k1 l1 k1 (Prod l1 k1 h1) (LiftedCoercible (SOP k2) * k1 f g) xs ys, HTrans (SOP k1) (SOP k2) l1 k1 h1 h2) => h1 f xs -> h2 g ys Source #
HTrans [k2] k2 [k1] k1 (NP k1) (NP k2) Source #
Methods htrans :: AllZipN (NP k1) l1 (NP k2) k1 l1 k1 (Prod l1 k1 h1) c xs ys => proxy c -> (forall x y. c x y => f x -> g y) -> h1 f xs -> h2 g ys Source # hcoerce :: (AllZipN (NP k1) l1 (NP k2) k1 l1 k1 (Prod l1 k1 h1) (LiftedCoercible (NP k2) * k1 f g) xs ys, HTrans (NP k1) (NP k2) l1 k1 h1 h2) => h1 f xs -> h2 g ys Source #
HTrans [k2] k2 [k1] k1 (NS k1) (NS k2) Source #
Methods htrans :: AllZipN (NS k1) l1 (NS k2) k1 l1 k1 (Prod l1 k1 h1) c xs ys => proxy c -> (forall x y. c x y => f x -> g y) -> h1 f xs -> h2 g ys Source # hcoerce :: (AllZipN (NS k1) l1 (NS k2) k1 l1 k1 (Prod l1 k1 h1) (LiftedCoercible (NS k2) * k1 f g) xs ys, HTrans (NS k1) (NS k2) l1 k1 h1 h2) => h1 f xs -> h2 g ys Source #

hfromI :: (AllZipN (Prod h1) (LiftedCoercible I f) xs ys, HTrans h1 h2) => h1 I xs -> h2 f ys Source #

Specialization of hcoerce.

Since: 0.3.1.0

htoI :: (AllZipN (Prod h1) (LiftedCoercible f I) xs ys, HTrans h1 h2) => h1 f xs -> h2 I ys Source #

Specialization of hcoerce.

Since: 0.3.1.0

Generalized applicative functor structure

Generalized pure

Generalized <*>

Derived functions

Collapsing homogeneous structures

Sequencing effects

Derived functions

Indexing into sums

Applying all injections

Expanding sums to products

Transformation of index lists and coercions

Generalized `pure`

Generalized `<*>`