Test.StrictCheck.Shaped

This module defines the Shaped typeclass, which is used to generically manipulate values as fixed-points of higher-order functors in order to analyze their structure, e.g. while observing evaluation.

If you just care about testing the strictness of functions over datatypes which are already instances of Shaped, you don't need to use this module.

Important note: To define new instances of Shaped for types which implement Generic, an empty instance will suffice, as all the methods of Shaped can be filled in by generic implementations. For example:

import GHC.Generics as GHC
import Generics.SOP as SOP

data D = C deriving (GHC.Generic)

instance SOP.Generic D
instance SOP.HasDatatypeInfo D

instance Shaped D

Using the DeriveAnyClass extension, this can be shortened to one line:

data D = C deriving (GHC.Generic, SOP.Generic, SOP.HasDatatypeInfo, Shaped)

Manual instances of Shaped are necessary for types which do not or cannot implement GHC's Generic typeclass, such as existential types, abstract types, and GADTs.

This module is heavily based upon the approach in Data.Functor.Foldable, which in turn is modeled after the paper "Functional Programming with Bananas, Lenses, Envelopes and Barbed Wire" (1991) by Erik Meijer, Maarten Fokkinga and Ross Paterson. If you don't yet understand recursion schemes and want to understand this module, it's probably a good idea to familiarize yourself with Data.Functor.Foldable before diving into this higher-order generalization.

Documentation

class Typeable a => Shaped (a :: *) where

When a type a is Shaped, we know how to convert it into a representation parameterized by an arbitrary functor f, so that Shape a f (the "shape of a parameterized by f") is structurally identical to the topmost structure of a, but with f wrapped around any subfields of a.

Note that this is not a recursive representation! The functor f in question wraps the original type of the field and not a Shape of that field.

For instance, the Shape of Either a b might be:

data EitherShape a b f
  = LeftShape  (f a)
  | RightShape (f b)

instance Shaped (Either a b) where
  type Shape (Either a b) = EitherShape a b
  ...

The shape of a primitive type should be isomorphic to the primitive type, with the functor parameter left unused.

Minimal complete definition

Nothing

Associated Types

type Shape a :: (* -> *) -> *

The Shape of an a is a type isomorphic to the outermost level of structure in an a, parameterized by the functor f, which is wrapped around any fields (of any type) in the original a.

Methods

project :: (forall x. Shaped x => x -> f x) -> a -> Shape a f

Given a function to expand any Shaped x into an f x, expand an a into a Shape a f

That is: convert the top-most level of structure in the given a into a Shape, calling the provided function on each field in the a to produce the f x necessary to fill that hole in the produced Shape a f.

Inverse to embed.

project :: GShaped a => (forall x. Shaped x => x -> f x) -> a -> Shape a f

Given a function to expand any Shaped x into an f x, expand an a into a Shape a f

That is: convert the top-most level of structure in the given a into a Shape, calling the provided function on each field in the a to produce the f x necessary to fill that hole in the produced Shape a f.

Inverse to embed.

embed :: (forall x. Shaped x => f x -> x) -> Shape a f -> a

Given a function to collapse any f x into a Shaped x, collapse a Shape a f into merely an a

That is: eliminate the top-most Shape by calling the provided function on each field in that Shape a f, and using the results to fill in the pieces necessary to build an a.

Inverse to project.

embed :: GShaped a => (forall x. Shaped x => f x -> x) -> Shape a f -> a

Given a function to collapse any f x into a Shaped x, collapse a Shape a f into merely an a

That is: eliminate the top-most Shape by calling the provided function on each field in that Shape a f, and using the results to fill in the pieces necessary to build an a.

Inverse to project.

match :: Shape a f -> Shape a g -> (forall xs. All Shaped xs => Flattened (Shape a) f xs -> Maybe (Flattened (Shape a) g xs) -> result) -> result

Given two Shapes of the same type a but parameterized by potentially different functors f and g, pattern-match on them to expose a uniform view on their fields (a Flattened (Shape a)) to a continuation which may operate on those fields to produce some result

If the two supplied Shapes do not structurally match, only the fields of the first are given to the continuation. If they do match, the fields of the second are also given, along with type-level proof that the types of the two sets of fields align.

This very general operation subsumes equality testing, mapping, zipping, shrinking, and many other structural operations over Shaped things.

It is somewhat difficult to manually write instances for this method, but consulting its generic implementation gMatch may prove helpful.

See Test.StrictCheck.Shaped.Flattened for more information.

match :: GShaped a => Shape a f -> Shape a g -> (forall xs. All Shaped xs => Flattened (Shape a) f xs -> Maybe (Flattened (Shape a) g xs) -> result) -> result

Given two Shapes of the same type a but parameterized by potentially different functors f and g, pattern-match on them to expose a uniform view on their fields (a Flattened (Shape a)) to a continuation which may operate on those fields to produce some result

If the two supplied Shapes do not structurally match, only the fields of the first are given to the continuation. If they do match, the fields of the second are also given, along with type-level proof that the types of the two sets of fields align.

This very general operation subsumes equality testing, mapping, zipping, shrinking, and many other structural operations over Shaped things.

It is somewhat difficult to manually write instances for this method, but consulting its generic implementation gMatch may prove helpful.

See Test.StrictCheck.Shaped.Flattened for more information.

render :: Shape a (K x) -> RenderLevel x

Convert a Shape a whose fields are some unknown constant type into a RenderLevel filled with that type

This is a specialized pretty-printing mechanism which allows for displaying counterexamples in a structured format. See the documentation for RenderLevel.

render :: (GShaped a, HasDatatypeInfo a) => Shape a (K x) -> RenderLevel x

Convert a Shape a whose fields are some unknown constant type into a RenderLevel filled with that type

This is a specialized pretty-printing mechanism which allows for displaying counterexamples in a structured format. See the documentation for RenderLevel.

Instances

Shaped Bool

Defined in Test.StrictCheck.Shaped

Associated Types

type Shape Bool :: (Type -> Type) -> Type

Methods

project :: (forall x. Shaped x => x -> f x) -> Bool -> Shape Bool f

embed :: (forall x. Shaped x => f x -> x) -> Shape Bool f -> Bool

match :: Shape Bool f -> Shape Bool g -> (forall (xs :: [Type]). All Shaped xs => Flattened (Shape Bool) f xs -> Maybe (Flattened (Shape Bool) g xs) -> result) -> result

render :: Shape Bool (K x) -> RenderLevel x

Shaped Char

Defined in Test.StrictCheck.Shaped

Associated Types

type Shape Char :: (Type -> Type) -> Type

Methods

project :: (forall x. Shaped x => x -> f x) -> Char -> Shape Char f

embed :: (forall x. Shaped x => f x -> x) -> Shape Char f -> Char

match :: Shape Char f -> Shape Char g -> (forall (xs :: [Type]). All Shaped xs => Flattened (Shape Char) f xs -> Maybe (Flattened (Shape Char) g xs) -> result) -> result

render :: Shape Char (K x) -> RenderLevel x

Shaped Double

Defined in Test.StrictCheck.Shaped

Associated Types

type Shape Double :: (Type -> Type) -> Type

Methods

project :: (forall x. Shaped x => x -> f x) -> Double -> Shape Double f

embed :: (forall x. Shaped x => f x -> x) -> Shape Double f -> Double

match :: Shape Double f -> Shape Double g -> (forall (xs :: [Type]). All Shaped xs => Flattened (Shape Double) f xs -> Maybe (Flattened (Shape Double) g xs) -> result) -> result

render :: Shape Double (K x) -> RenderLevel x

Shaped Float

Defined in Test.StrictCheck.Shaped

Associated Types

type Shape Float :: (Type -> Type) -> Type

Methods

project :: (forall x. Shaped x => x -> f x) -> Float -> Shape Float f

embed :: (forall x. Shaped x => f x -> x) -> Shape Float f -> Float

match :: Shape Float f -> Shape Float g -> (forall (xs :: [Type]). All Shaped xs => Flattened (Shape Float) f xs -> Maybe (Flattened (Shape Float) g xs) -> result) -> result

render :: Shape Float (K x) -> RenderLevel x

Shaped Int

Defined in Test.StrictCheck.Shaped

Associated Types

type Shape Int :: (Type -> Type) -> Type

Methods

project :: (forall x. Shaped x => x -> f x) -> Int -> Shape Int f

embed :: (forall x. Shaped x => f x -> x) -> Shape Int f -> Int

match :: Shape Int f -> Shape Int g -> (forall (xs :: [Type]). All Shaped xs => Flattened (Shape Int) f xs -> Maybe (Flattened (Shape Int) g xs) -> result) -> result

render :: Shape Int (K x) -> RenderLevel x

Shaped Integer

Defined in Test.StrictCheck.Shaped

Associated Types

type Shape Integer :: (Type -> Type) -> Type

Methods

project :: (forall x. Shaped x => x -> f x) -> Integer -> Shape Integer f

embed :: (forall x. Shaped x => f x -> x) -> Shape Integer f -> Integer

match :: Shape Integer f -> Shape Integer g -> (forall (xs :: [Type]). All Shaped xs => Flattened (Shape Integer) f xs -> Maybe (Flattened (Shape Integer) g xs) -> result) -> result

render :: Shape Integer (K x) -> RenderLevel x

Shaped Ordering

Defined in Test.StrictCheck.Shaped

Associated Types

type Shape Ordering :: (Type -> Type) -> Type

Methods

project :: (forall x. Shaped x => x -> f x) -> Ordering -> Shape Ordering f

embed :: (forall x. Shaped x => f x -> x) -> Shape Ordering f -> Ordering

match :: Shape Ordering f -> Shape Ordering g -> (forall (xs :: [Type]). All Shaped xs => Flattened (Shape Ordering) f xs -> Maybe (Flattened (Shape Ordering) g xs) -> result) -> result

render :: Shape Ordering (K x) -> RenderLevel x

Shaped Rational

Defined in Test.StrictCheck.Shaped

Associated Types

type Shape Rational :: (Type -> Type) -> Type

Methods

project :: (forall x. Shaped x => x -> f x) -> Rational -> Shape Rational f

embed :: (forall x. Shaped x => f x -> x) -> Shape Rational f -> Rational

match :: Shape Rational f -> Shape Rational g -> (forall (xs :: [Type]). All Shaped xs => Flattened (Shape Rational) f xs -> Maybe (Flattened (Shape Rational) g xs) -> result) -> result

render :: Shape Rational (K x) -> RenderLevel x

Shaped Word

Defined in Test.StrictCheck.Shaped

Associated Types

type Shape Word :: (Type -> Type) -> Type

Methods

project :: (forall x. Shaped x => x -> f x) -> Word -> Shape Word f

embed :: (forall x. Shaped x => f x -> x) -> Shape Word f -> Word

match :: Shape Word f -> Shape Word g -> (forall (xs :: [Type]). All Shaped xs => Flattened (Shape Word) f xs -> Maybe (Flattened (Shape Word) g xs) -> result) -> result

render :: Shape Word (K x) -> RenderLevel x

Shaped ()

Defined in Test.StrictCheck.Shaped

Associated Types

type Shape () :: (Type -> Type) -> Type

Methods

project :: (forall x. Shaped x => x -> f x) -> () -> Shape () f

embed :: (forall x. Shaped x => f x -> x) -> Shape () f -> ()

match :: Shape () f -> Shape () g -> (forall (xs :: [Type]). All Shaped xs => Flattened (Shape ()) f xs -> Maybe (Flattened (Shape ()) g xs) -> result) -> result

render :: Shape () (K x) -> RenderLevel x

Shaped Omega

Defined in Test.StrictCheck.Internal.Omega

Associated Types

type Shape Omega :: (Type -> Type) -> Type

Methods

project :: (forall x. Shaped x => x -> f x) -> Omega -> Shape Omega f

embed :: (forall x. Shaped x => f x -> x) -> Shape Omega f -> Omega

match :: Shape Omega f -> Shape Omega g -> (forall (xs :: [Type]). All Shaped xs => Flattened (Shape Omega) f xs -> Maybe (Flattened (Shape Omega) g xs) -> result) -> result

render :: Shape Omega (K x) -> RenderLevel x

Shaped Key

Defined in Test.StrictCheck.Examples.Map

Associated Types

type Shape Key :: (Type -> Type) -> Type

Methods

project :: (forall x. Shaped x => x -> f x) -> Key -> Shape Key f

embed :: (forall x. Shaped x => f x -> x) -> Shape Key f -> Key

match :: Shape Key f -> Shape Key g -> (forall (xs :: [Type]). All Shaped xs => Flattened (Shape Key) f xs -> Maybe (Flattened (Shape Key) g xs) -> result) -> result

render :: Shape Key (K x) -> RenderLevel x

Shaped a => Shaped [a]

Defined in Test.StrictCheck.Shaped

Associated Types

type Shape [a] :: (Type -> Type) -> Type

Methods

project :: (forall x. Shaped x => x -> f x) -> [a] -> Shape [a] f

embed :: (forall x. Shaped x => f x -> x) -> Shape [a] f -> [a]

match :: Shape [a] f -> Shape [a] g -> (forall (xs :: [Type]). All Shaped xs => Flattened (Shape [a]) f xs -> Maybe (Flattened (Shape [a]) g xs) -> result) -> result

render :: Shape [a] (K x) -> RenderLevel x

Shaped a => Shaped (Maybe a)

Defined in Test.StrictCheck.Shaped

Associated Types

type Shape (Maybe a) :: (Type -> Type) -> Type

Methods

project :: (forall x. Shaped x => x -> f x) -> Maybe a -> Shape (Maybe a) f

embed :: (forall x. Shaped x => f x -> x) -> Shape (Maybe a) f -> Maybe a

match :: Shape (Maybe a) f -> Shape (Maybe a) g -> (forall (xs :: [Type]). All Shaped xs => Flattened (Shape (Maybe a)) f xs -> Maybe (Flattened (Shape (Maybe a)) g xs) -> result) -> result

render :: Shape (Maybe a) (K x) -> RenderLevel x

(Typeable a, Eq a, Show a) => Shaped (Complex a)

Defined in Test.StrictCheck.Shaped

Associated Types

type Shape (Complex a) :: (Type -> Type) -> Type

Methods

project :: (forall x. Shaped x => x -> f x) -> Complex a -> Shape (Complex a) f

embed :: (forall x. Shaped x => f x -> x) -> Shape (Complex a) f -> Complex a

match :: Shape (Complex a) f -> Shape (Complex a) g -> (forall (xs :: [Type]). All Shaped xs => Flattened (Shape (Complex a)) f xs -> Maybe (Flattened (Shape (Complex a)) g xs) -> result) -> result

render :: Shape (Complex a) (K x) -> RenderLevel x

(Typeable a, Typeable b) => Shaped (a -> b)

Defined in Test.StrictCheck.Shaped

Associated Types

type Shape (a -> b) :: (Type -> Type) -> Type

Methods

project :: (forall x. Shaped x => x -> f x) -> (a -> b) -> Shape (a -> b) f

embed :: (forall x. Shaped x => f x -> x) -> Shape (a -> b) f -> a -> b

match :: Shape (a -> b) f -> Shape (a -> b) g -> (forall (xs :: [Type]). All Shaped xs => Flattened (Shape (a -> b)) f xs -> Maybe (Flattened (Shape (a -> b)) g xs) -> result) -> result

render :: Shape (a -> b) (K x) -> RenderLevel x

(Shaped a, Shaped b) => Shaped (Either a b)

Defined in Test.StrictCheck.Shaped

Associated Types

type Shape (Either a b) :: (Type -> Type) -> Type

Methods

project :: (forall x. Shaped x => x -> f x) -> Either a b -> Shape (Either a b) f

embed :: (forall x. Shaped x => f x -> x) -> Shape (Either a b) f -> Either a b

match :: Shape (Either a b) f -> Shape (Either a b) g -> (forall (xs :: [Type]). All Shaped xs => Flattened (Shape (Either a b)) f xs -> Maybe (Flattened (Shape (Either a b)) g xs) -> result) -> result

render :: Shape (Either a b) (K x) -> RenderLevel x

(Shaped a, Shaped b) => Shaped (a, b)

Defined in Test.StrictCheck.Shaped

Associated Types

type Shape (a, b) :: (Type -> Type) -> Type

Methods

project :: (forall x. Shaped x => x -> f x) -> (a, b) -> Shape (a, b) f

embed :: (forall x. Shaped x => f x -> x) -> Shape (a, b) f -> (a, b)

match :: Shape (a, b) f -> Shape (a, b) g -> (forall (xs :: [Type]). All Shaped xs => Flattened (Shape (a, b)) f xs -> Maybe (Flattened (Shape (a, b)) g xs) -> result) -> result

render :: Shape (a, b) (K x) -> RenderLevel x

(Shaped k, Shaped v) => Shaped (Map k v)

Defined in Test.StrictCheck.Examples.Map

Associated Types

type Shape (Map k v) :: (Type -> Type) -> Type

Methods

project :: (forall x. Shaped x => x -> f x) -> Map k v -> Shape (Map k v) f

embed :: (forall x. Shaped x => f x -> x) -> Shape (Map k v) f -> Map k v

match :: Shape (Map k v) f -> Shape (Map k v) g -> (forall (xs :: [Type]). All Shaped xs => Flattened (Shape (Map k v)) f xs -> Maybe (Flattened (Shape (Map k v)) g xs) -> result) -> result

render :: Shape (Map k v) (K x) -> RenderLevel x

(Shaped a, Shaped b, Shaped c) => Shaped (a, b, c)

Defined in Test.StrictCheck.Shaped

Associated Types

type Shape (a, b, c) :: (Type -> Type) -> Type

Methods

project :: (forall x. Shaped x => x -> f x) -> (a, b, c) -> Shape (a, b, c) f

embed :: (forall x. Shaped x => f x -> x) -> Shape (a, b, c) f -> (a, b, c)

match :: Shape (a, b, c) f -> Shape (a, b, c) g -> (forall (xs :: [Type]). All Shaped xs => Flattened (Shape (a, b, c)) f xs -> Maybe (Flattened (Shape (a, b, c)) g xs) -> result) -> result

render :: Shape (a, b, c) (K x) -> RenderLevel x

(Shaped a, Shaped b, Shaped c, Shaped d) => Shaped (a, b, c, d)

Defined in Test.StrictCheck.Shaped

Associated Types

type Shape (a, b, c, d) :: (Type -> Type) -> Type

Methods

project :: (forall x. Shaped x => x -> f x) -> (a, b, c, d) -> Shape (a, b, c, d) f

embed :: (forall x. Shaped x => f x -> x) -> Shape (a, b, c, d) f -> (a, b, c, d)

match :: Shape (a, b, c, d) f -> Shape (a, b, c, d) g -> (forall (xs :: [Type]). All Shaped xs => Flattened (Shape (a, b, c, d)) f xs -> Maybe (Flattened (Shape (a, b, c, d)) g xs) -> result) -> result

render :: Shape (a, b, c, d) (K x) -> RenderLevel x

(Shaped a, Shaped b, Shaped c, Shaped d, Shaped e) => Shaped (a, b, c, d, e)

Defined in Test.StrictCheck.Shaped

Associated Types

type Shape (a, b, c, d, e) :: (Type -> Type) -> Type

Methods

project :: (forall x. Shaped x => x -> f x) -> (a, b, c, d, e) -> Shape (a, b, c, d, e) f

embed :: (forall x. Shaped x => f x -> x) -> Shape (a, b, c, d, e) f -> (a, b, c, d, e)

match :: Shape (a, b, c, d, e) f -> Shape (a, b, c, d, e) g -> (forall (xs :: [Type]). All Shaped xs => Flattened (Shape (a, b, c, d, e)) f xs -> Maybe (Flattened (Shape (a, b, c, d, e)) g xs) -> result) -> result

render :: Shape (a, b, c, d, e) (K x) -> RenderLevel x

(Shaped a, Shaped b, Shaped c, Shaped d, Shaped e, Shaped f) => Shaped (a, b, c, d, e, f)

Defined in Test.StrictCheck.Shaped

Associated Types

type Shape (a, b, c, d, e, f) :: (Type -> Type) -> Type

Methods

project :: (forall x. Shaped x => x -> f0 x) -> (a, b, c, d, e, f) -> Shape (a, b, c, d, e, f) f0

embed :: (forall x. Shaped x => f0 x -> x) -> Shape (a, b, c, d, e, f) f0 -> (a, b, c, d, e, f)

match :: Shape (a, b, c, d, e, f) f0 -> Shape (a, b, c, d, e, f) g -> (forall (xs :: [Type]). All Shaped xs => Flattened (Shape (a, b, c, d, e, f)) f0 xs -> Maybe (Flattened (Shape (a, b, c, d, e, f)) g xs) -> result) -> result

render :: Shape (a, b, c, d, e, f) (K x) -> RenderLevel x

(Shaped a, Shaped b, Shaped c, Shaped d, Shaped e, Shaped f, Shaped g) => Shaped (a, b, c, d, e, f, g)

Defined in Test.StrictCheck.Shaped

Associated Types

type Shape (a, b, c, d, e, f, g) :: (Type -> Type) -> Type

Methods

project :: (forall x. Shaped x => x -> f0 x) -> (a, b, c, d, e, f, g) -> Shape (a, b, c, d, e, f, g) f0

embed :: (forall x. Shaped x => f0 x -> x) -> Shape (a, b, c, d, e, f, g) f0 -> (a, b, c, d, e, f, g)

match :: Shape (a, b, c, d, e, f, g) f0 -> Shape (a, b, c, d, e, f, g) g0 -> (forall (xs :: [Type]). All Shaped xs => Flattened (Shape (a, b, c, d, e, f, g)) f0 xs -> Maybe (Flattened (Shape (a, b, c, d, e, f, g)) g0 xs) -> result) -> result

render :: Shape (a, b, c, d, e, f, g) (K x) -> RenderLevel x

module Test.StrictCheck.Shaped.Flattened

Fixed-points of Shapes

newtype (f :: * -> *) % (a :: *) :: * where

A value of type f % a has the same structure as an a, but with the structure of the functor f interleaved at every field (including ones of types other than a). Read this type aloud as "a interleaved with f's".

Constructors

Wrap :: f (Shape a ((%) f)) -> f % a

Instances

Shaped a => Eq (Demand a)

Demands are compared for equality using eqDemand; see its documentation for details

Defined in Test.StrictCheck.Demand

Methods

(==) :: Demand a -> Demand a -> Bool

(/=) :: Demand a -> Demand a -> Bool

Shaped a => Show (Demand a)

Defined in Test.StrictCheck.Demand

Methods

showsPrec :: Int -> Demand a -> ShowS

show :: Demand a -> String

showList :: [Demand a] -> ShowS

Folds and unfolds over fixed-points of Shapes

unwrap :: (f % a) -> f (Shape a ((%) f))

Look inside a single level of an interleaved f % a. Inverse to the Wrap constructor.

interleave :: (Functor f, Shaped a) => (forall x. x -> f x) -> a -> f % a

Interleave an f-structure at every recursive level of some a, given some way of generating a single level of structure x -> f x.

This is a special case of unfold.

(%) :: forall a f. (Functor f, Shaped a) => (forall x. x -> f x) -> a -> f % a

An infix synonym for interleave

fuse :: (Functor f, Shaped a) => (forall x. f x -> x) -> (f % a) -> a

Fuse the interleaved f-structure out of a recursively interleaved f % a, given some way of fusing a single level f x -> x.

This is a special case of fold.

translate :: forall a f g. Shaped a => (forall x. Shaped x => f x -> g x) -> Shape a f -> Shape a g

Map a function across all the fields in a Shape

This function may change the functor over which the Shape is parameterized. It can assume recursively that all the fields in the Shape are themselves instances of Shaped (which they should be!). This means that you can nest calls to translate recursively.

fold :: forall a f g. (Functor f, Shaped a) => (forall x. Shaped x => f (Shape x g) -> g x) -> (f % a) -> g a

The equivalent of a fold (catamorphism) over recursively Shaped values

Given a function which folds an f containing some Shape x g into a g x, recursively fold any interleaved f % a into a g a.

unfold :: forall a f g. (Functor g, Shaped a) => (forall x. Shaped x => f x -> g (Shape x f)) -> f a -> g % a

The equivalent of an unfold (anamorphism) over recursively Shaped values

Given a function which unfolds an f x into a g containing some Shape x f, corecursively unfold any f a into an interleaved g % a.

unzipWith :: (All Functor [f, g, h], Shaped a) => (forall x. f x -> (g x, h x)) -> (f % a) -> (g % a, h % a)

A higher-kinded unzipWith, operating over interleaved structures

Given a function splitting some f x into a functor-product Product g h x, recursively split an interleaved f % a into two interleaved structures: one built of g-shapes and one of h-shapes.

Note that Product ((%) g) ((%) h) a is isomorphic to (g % a, h % a); to get the latter, pattern-match on the Pair constructor of Product.

Rendering Shaped things as structured text

type QName = (ModuleName, DatatypeName, String)

A QName is a qualified name

Note: > type ModuleName = String > type DatatypeName = String

data Rendered f

Rendered f is the fixed-point of f composed with RenderLevel: it alternates between f shapes and RenderLevels. Usually, f will be the identity functor I, but not always.

Constructors

RWrap (f (RenderLevel (Rendered f)))

data RenderLevel x

RenderLevel is a functor whose outer shape contains all the information about how to pretty-format the outermost Shape of some value. We use parametricity to make it difficult to construct incorrect render methods, by asking the user merely to produce a single RenderLevel and stitching nested RenderLevels into complete Rendered trees.

Constructors

ConstructorD QName [x]

A prefix constructor, and a list of its fields

InfixD QName Associativity Fixity x x

An infix constructor, its associativity and fixity, and its two fields

RecordD QName [(QName, x)]

A record constructor, and a list of its field names paired with fields

CustomD Fixity [Either (Either String (ModuleName, String)) (Fixity, x)]

A custom pretty-printing representation (i.e. for abstract types), which records a fixity and a list of tokens of three varieties: 1) raw strings, 2) qualified strings (from some module), or 3) actual fields, annotated with their fixity

Instances

Functor RenderLevel

Defined in Test.StrictCheck.Shaped

Methods

fmap :: (a -> b) -> RenderLevel a -> RenderLevel b

(<$) :: a -> RenderLevel b -> RenderLevel a

Eq x => Eq (RenderLevel x)

Defined in Test.StrictCheck.Shaped

Methods

(==) :: RenderLevel x -> RenderLevel x -> Bool

(/=) :: RenderLevel x -> RenderLevel x -> Bool

Ord x => Ord (RenderLevel x)

Defined in Test.StrictCheck.Shaped

Methods

compare :: RenderLevel x -> RenderLevel x -> Ordering

(<) :: RenderLevel x -> RenderLevel x -> Bool

(<=) :: RenderLevel x -> RenderLevel x -> Bool

(>) :: RenderLevel x -> RenderLevel x -> Bool

(>=) :: RenderLevel x -> RenderLevel x -> Bool

max :: RenderLevel x -> RenderLevel x -> RenderLevel x

min :: RenderLevel x -> RenderLevel x -> RenderLevel x

Show x => Show (RenderLevel x)

Defined in Test.StrictCheck.Shaped

Methods

showsPrec :: Int -> RenderLevel x -> ShowS

show :: RenderLevel x -> String

showList :: [RenderLevel x] -> ShowS

renderfold :: forall a f. (Shaped a, Functor f) => (f % a) -> Rendered f

TODO: document this strange function

Convert an f % a into a structured pretty-printing representation, suitable for further display/processing

Tools for manually writing instances of Shaped

Implementing Shaped for primitive types

newtype Prim (x :: *) (f :: * -> *)

The Shape of a primitive type should be equivalent to the type itself. However, this does not have the right kind to be used as a Shape.

The Prim newtype solves this problem. By defining the Shape of some primitive type p to be Prim p, you can use the methods projectPrim, embedPrim, matchPrim, and prettyPrim to completely fill in the definition of the Shaped class for a primitive type.

Note: It is only appropriate to use this Shape representation when a type really is primitive, in that it contains no interesting substructure. If you use the Prim representation inappropriately, StrictCheck will not be able to inspect the richer structure of the type in question.

Constructors

Prim x

Instances

Eq x => Eq (Prim x f)

Defined in Test.StrictCheck.Shaped

Methods

(==) :: Prim x f -> Prim x f -> Bool

(/=) :: Prim x f -> Prim x f -> Bool

Num x => Num (Prim x f)

Defined in Test.StrictCheck.Shaped

Methods

(+) :: Prim x f -> Prim x f -> Prim x f

(-) :: Prim x f -> Prim x f -> Prim x f

(*) :: Prim x f -> Prim x f -> Prim x f

negate :: Prim x f -> Prim x f

abs :: Prim x f -> Prim x f

signum :: Prim x f -> Prim x f

fromInteger :: Integer -> Prim x f

Ord x => Ord (Prim x f)

Defined in Test.StrictCheck.Shaped

Methods

compare :: Prim x f -> Prim x f -> Ordering

(<) :: Prim x f -> Prim x f -> Bool

(<=) :: Prim x f -> Prim x f -> Bool

(>) :: Prim x f -> Prim x f -> Bool

(>=) :: Prim x f -> Prim x f -> Bool

max :: Prim x f -> Prim x f -> Prim x f

min :: Prim x f -> Prim x f -> Prim x f

Show x => Show (Prim x f)

Defined in Test.StrictCheck.Shaped

Methods

showsPrec :: Int -> Prim x f -> ShowS

show :: Prim x f -> String

showList :: [Prim x f] -> ShowS

unPrim :: Prim x f -> x

Get the wrapped x out of a Prim x f (inverse to the Prim constructor)

projectPrim :: (forall x. Shaped x => x -> f x) -> a -> Prim a f

Generic implementation of project for any primitive type whose Shape is is represented as a Prim newtype

embedPrim :: (forall x. Shaped x => f x -> x) -> Prim a f -> a

Generic implementation of embed for any primitive type whose Shape is is represented as a Prim newtype

matchPrim :: Eq a => Prim a f -> Prim a g -> (forall xs. All Shaped xs => Flattened (Prim a) f xs -> Maybe (Flattened (Prim a) g xs) -> result) -> result

Generic implementation of match for any primitive type whose Shape is is represented as a Prim newtype with an underlying Eq instance

flatPrim :: a -> Flattened (Prim a) g '[]

Helper for writing match instances for primitive types which don't have Eq instance

This generates a Flattened appropriate for using in the implementation of match. For more documentation on how to use this, see the documentation of match.

renderPrim :: Show a => Prim a (K x) -> RenderLevel x

Generic implementation of render for any primitive type whose Shape is is represented as a Prim newtype

renderConstant :: String -> RenderLevel x

Given some string, generate a custom pretty-printing representation which just shows the string

Implementing Shaped for container types

newtype Containing h a f

The Shape of a spine-strict container (i.e. a Map or Set) is the same as a container of demands on its elements. However, this does not have the right kind to be used as a Shape.

The Containing newtype solves this problem. By defining the Shape of some container (C a) to be (C Containing a), you can use the methods projectContainer and embedContainer to implement project and embed for your container type (although you will still need to manually define match and render).

Constructors

Container (h (f a))

Instances

Eq (h (f a)) => Eq (Containing h a f)

Defined in Test.StrictCheck.Shaped

Methods

(==) :: Containing h a f -> Containing h a f -> Bool

(/=) :: Containing h a f -> Containing h a f -> Bool

Ord (h (f a)) => Ord (Containing h a f)

Defined in Test.StrictCheck.Shaped

Methods

compare :: Containing h a f -> Containing h a f -> Ordering

(<) :: Containing h a f -> Containing h a f -> Bool

(<=) :: Containing h a f -> Containing h a f -> Bool

(>) :: Containing h a f -> Containing h a f -> Bool

(>=) :: Containing h a f -> Containing h a f -> Bool

max :: Containing h a f -> Containing h a f -> Containing h a f

min :: Containing h a f -> Containing h a f -> Containing h a f

Show (h (f a)) => Show (Containing h a f)

Defined in Test.StrictCheck.Shaped

Methods

showsPrec :: Int -> Containing h a f -> ShowS

show :: Containing h a f -> String

showList :: [Containing h a f] -> ShowS

projectContainer :: (Functor c, Shaped a) => (forall x. Shaped x => x -> f x) -> c a -> Containing c a f

Generic implementation of project for any container type whose Shape is represented as a Containing newtype

embedContainer :: (Functor c, Shaped a) => (forall x. Shaped x => f x -> x) -> Containing c a f -> c a

Generic implementation of embed for any container type whose Shape is represented as a Containing newtype

Generic implementation of the methods of Shaped

type GShaped a = (Generic a, Shape a ~ GShape a, All2 Shaped (Code a), SListI (Code a), All SListI (Code a))

The collection of constraints necessary for a type to be given a generic implementation of the Shaped methods

newtype GShape a f

The Shape used for generic implementations of Shaped

This wraps a sum-of-products representation from Generics.SOP.

Constructors

GS (NS (NP f) (Code a))

gProject :: GShaped a => (forall x. Shaped x => x -> f x) -> a -> Shape a f

Generic project

gEmbed :: GShaped a => (forall x. Shaped x => f x -> x) -> Shape a f -> a

Generic embed

gMatch :: forall a f g result. GShaped a => Shape a f -> Shape a g -> (forall xs. All Shaped xs => Flattened (Shape a) f xs -> Maybe (Flattened (Shape a) g xs) -> result) -> result

Generic match

gRender :: forall a x. (HasDatatypeInfo a, GShaped a) => Shape a (K x) -> RenderLevel x

Generic render