Homoiconic.Constrained

Constrained FAlgebras

class Typeable alg => FAlgebra alg where

Minimal complete definition

runSig1, runSig0, mapRun

Associated Types

data Sig alg (t :: [Tag]) a

Methods

runSig1 :: alg a => proxy a -> Sig alg (s ': t) (AppTags t a) -> AppTags (s ': t) a

runSig0 :: alg a => proxy a -> Sig alg t (AppTags t a) -> AppTags t a

mapRun :: FreeConstraints t' a => (forall s. Free (Sig alg') s a -> AppTags s a) -> Sig alg t (Free (Sig alg') t' a) -> Sig alg t (AppTags t' a)

type AST alg t a = Free (Sig alg) t a

runAST :: forall alg t a. (FAlgebra alg, alg a) => Free (Sig alg) t a -> AppTags t a

Dealing with Type Families

type Tag = Type

This type synonym represents the kind of tags. Using this synonym requires the -XTypeInType extension.

NOTE: We would get more type safety if this were implemented as an open kind, but open kinds aren't yet implemented in GHC.

type family AppTag (t :: Tag) (a :: Type)

Apply a single tag to a type

type family AppTags (t :: [Tag]) (a :: Type) :: Type where ...

Apply a (possibly empty) list of tags to a type

Equations

AppTags '[] a = a

AppTags (x ': xs) a = AppTag x (AppTags xs a)

type family ConsTag (t :: Tag) (ts :: [Tag]) :: [Tag]

An alternative method for constructing kinds of [Tag] that obeys the equality constraints

Constrained Free Monad

data Free f t a where

The constrained free monad

Constructors

Free1 :: FreeConstraints t a => f (s ': t) (Free f t a) -> Free f (s ': t) a

Free0 :: FreeConstraints t a => f t (Free f t a) -> Free f t a

Pure :: AppTags t a -> Free f t a

Instances

(Show (AppTags t a), Show (f t (Free f t a)), ShowUntag (f t (Free f t a))) => Show (Free f t a)

Methods

showsPrec :: Int -> Free f t a -> ShowS

show :: Free f t a -> String

showList :: [Free f t a] -> ShowS

type family FreeConstraints (t :: [Tag]) (a :: Type) :: Constraint

The constraints we are placing on the free monad

class MkFree s t a where

mkFree is a smart constructor that is implemented by either Free1 or Free0 depending on how ConsTag is implemented

Minimal complete definition

mkFree

Methods

mkFree :: proxy s -> f (ConsTag s t) (Free f t a) -> Free f (ConsTag s t) a

Converting between FAlgebras

class (FAlgebra alg1, FAlgebra alg2) => View alg1 t1 alg2 t2 where

Minimal complete definition

embedSig, unsafeExtractSig

Methods

embedSig :: Sig alg1 t1 a -> Sig alg2 t2 a

unsafeExtractSig :: Sig alg2 t2 a -> Sig alg1 t1 a

Instances

FAlgebra alg => View alg t alg t

Methods

embedSig :: Sig alg t a -> Sig alg t a

unsafeExtractSig :: Sig alg t a -> Sig alg t a

Variable definitions

data Var

Instances

Eq Var

Methods

(==) :: Var -> Var -> Bool

(/=) :: Var -> Var -> Bool

Show Var

Methods

showsPrec :: Int -> Var -> ShowS

show :: Var -> String

showList :: [Var] -> ShowS

var1 :: AppTags t Var ~ Var => AST alg t Var

var2 :: AppTags t Var ~ Var => AST alg t Var

var3 :: AppTags t Var ~ Var => AST alg t Var

Template Haskell

mkFAlgebra :: Name -> Q [Dec]

Generates the FAlgebra instance for the specified name and all of its dependencies recursively

mkTag :: Name -> Q [Dec]

Constructs the needed declarations for a type family assuming no constraints on the type family

mkTagFromCxt :: Cxt -> Name -> Q [Dec]

Constructs the declarations for a type family that is constrainted by some context. Currently, the only supported constraints are idempocency constraints.

Helper functions

unsafeExtractSigTag0 :: View alg1 '[] alg2 t => Sig alg2 t (Free (Sig alg2) t a) -> Sig alg1 '[] (Free (Sig alg2) t a)

unsafeExtractSigTag :: View alg1 '[s] alg2 (s ': t) => Sig alg2 (s ': t) (Free (Sig alg2) t a) -> Sig alg1 '[s] (Free (Sig alg2) t a)

unsafeCoerceSigTag :: proxy t' -> Sig alg t a -> Sig alg t' a

runSig1Snoc :: forall proxy alg a s ttt t u. (FAlgebra alg, alg (AppTag u a)) => Proxy (u :: Tag) -> Proxy (s :: Tag) -> Proxy (t :: [Tag]) -> Proxy a -> Sig alg ttt (AppTags t a) -> AppTag s (AppTags t a)

runSig0Snoc :: forall proxy alg a t u. (FAlgebra alg, alg (AppTag u a)) => Proxy u -> Proxy a -> Sig alg t (AppTags (t `Snoc` u) a) -> AppTags (t `Snoc` u) a

embedSigTag :: View alg1 (t ': t1) alg2 (t ': t2) => Sig alg1 (t ': t1) a -> Sig alg2 (t ': t2) a

type family Snoc (xs :: [k]) (y :: k) where ...

Append an element to the end of a type list

Equations

Snoc '[] y = '[y]

Snoc (x ': xs) y = x ': Snoc xs y

Other need types

data Proxy k t :: forall k. k -> *

A concrete, poly-kinded proxy type

Constructors

Proxy

Instances

Monad (Proxy *)

Methods

(>>=) :: Proxy * a -> (a -> Proxy * b) -> Proxy * b

(>>) :: Proxy * a -> Proxy * b -> Proxy * b

return :: a -> Proxy * a

fail :: String -> Proxy * a

Functor (Proxy *)

Methods

fmap :: (a -> b) -> Proxy * a -> Proxy * b

(<$) :: a -> Proxy * b -> Proxy * a

Applicative (Proxy *)

Methods

pure :: a -> Proxy * a

(<*>) :: Proxy * (a -> b) -> Proxy * a -> Proxy * b

(*>) :: Proxy * a -> Proxy * b -> Proxy * b

(<*) :: Proxy * a -> Proxy * b -> Proxy * a

Foldable (Proxy *)

Methods

fold :: Monoid m => Proxy * m -> m

foldMap :: Monoid m => (a -> m) -> Proxy * a -> m

foldr :: (a -> b -> b) -> b -> Proxy * a -> b

foldr' :: (a -> b -> b) -> b -> Proxy * a -> b

foldl :: (b -> a -> b) -> b -> Proxy * a -> b

foldl' :: (b -> a -> b) -> b -> Proxy * a -> b

foldr1 :: (a -> a -> a) -> Proxy * a -> a

foldl1 :: (a -> a -> a) -> Proxy * a -> a

toList :: Proxy * a -> [a]

null :: Proxy * a -> Bool

length :: Proxy * a -> Int

elem :: Eq a => a -> Proxy * a -> Bool

maximum :: Ord a => Proxy * a -> a

minimum :: Ord a => Proxy * a -> a

sum :: Num a => Proxy * a -> a

product :: Num a => Proxy * a -> a

Traversable (Proxy *)

Methods

traverse :: Applicative f => (a -> f b) -> Proxy * a -> f (Proxy * b)

sequenceA :: Applicative f => Proxy * (f a) -> f (Proxy * a)

mapM :: Monad m => (a -> m b) -> Proxy * a -> m (Proxy * b)

sequence :: Monad m => Proxy * (m a) -> m (Proxy * a)

Generic1 (Proxy *)

Associated Types

type Rep1 (Proxy * :: * -> *) :: * -> *

Methods

from1 :: Proxy * a -> Rep1 (Proxy *) a

to1 :: Rep1 (Proxy *) a -> Proxy * a

Alternative (Proxy *)

Methods

empty :: Proxy * a

(<|>) :: Proxy * a -> Proxy * a -> Proxy * a

some :: Proxy * a -> Proxy * [a]

many :: Proxy * a -> Proxy * [a]

MonadPlus (Proxy *)

Methods

mzero :: Proxy * a

mplus :: Proxy * a -> Proxy * a -> Proxy * a

Bounded (Proxy k s)

Methods

minBound :: Proxy k s

maxBound :: Proxy k s

Enum (Proxy k s)

Methods

succ :: Proxy k s -> Proxy k s

pred :: Proxy k s -> Proxy k s

toEnum :: Int -> Proxy k s

fromEnum :: Proxy k s -> Int

enumFrom :: Proxy k s -> [Proxy k s]

enumFromThen :: Proxy k s -> Proxy k s -> [Proxy k s]

enumFromTo :: Proxy k s -> Proxy k s -> [Proxy k s]

enumFromThenTo :: Proxy k s -> Proxy k s -> Proxy k s -> [Proxy k s]

Eq (Proxy k s)

Methods

(==) :: Proxy k s -> Proxy k s -> Bool

(/=) :: Proxy k s -> Proxy k s -> Bool

Ord (Proxy k s)

Methods

compare :: Proxy k s -> Proxy k s -> Ordering

(<) :: Proxy k s -> Proxy k s -> Bool

(<=) :: Proxy k s -> Proxy k s -> Bool

(>) :: Proxy k s -> Proxy k s -> Bool

(>=) :: Proxy k s -> Proxy k s -> Bool

max :: Proxy k s -> Proxy k s -> Proxy k s

min :: Proxy k s -> Proxy k s -> Proxy k s

Read (Proxy k s)

Methods

readsPrec :: Int -> ReadS (Proxy k s)

readList :: ReadS [Proxy k s]

readPrec :: ReadPrec (Proxy k s)

readListPrec :: ReadPrec [Proxy k s]

Show (Proxy k s)

Methods

showsPrec :: Int -> Proxy k s -> ShowS

show :: Proxy k s -> String

showList :: [Proxy k s] -> ShowS

Ix (Proxy k s)

Methods

range :: (Proxy k s, Proxy k s) -> [Proxy k s]

index :: (Proxy k s, Proxy k s) -> Proxy k s -> Int

unsafeIndex :: (Proxy k s, Proxy k s) -> Proxy k s -> Int

inRange :: (Proxy k s, Proxy k s) -> Proxy k s -> Bool

rangeSize :: (Proxy k s, Proxy k s) -> Int

unsafeRangeSize :: (Proxy k s, Proxy k s) -> Int

Generic (Proxy k t)

Associated Types

type Rep (Proxy k t) :: * -> *

Methods

from :: Proxy k t -> Rep (Proxy k t) x

to :: Rep (Proxy k t) x -> Proxy k t

Monoid (Proxy k s)

Methods

mempty :: Proxy k s

mappend :: Proxy k s -> Proxy k s -> Proxy k s

mconcat :: [Proxy k s] -> Proxy k s

type Rep1 (Proxy *)

type Rep1 (Proxy *) = D1 (MetaData "Proxy" "Data.Proxy" "base" False) (C1 (MetaCons "Proxy" PrefixI False) U1)

type Rep (Proxy k t)

type Rep (Proxy k t) = D1 (MetaData "Proxy" "Data.Proxy" "base" False) (C1 (MetaCons "Proxy" PrefixI False) U1)

class Typeable k a

The class Typeable allows a concrete representation of a type to be calculated.

Minimal complete definition

typeRep#

data Constraint :: *

The kind of constraints, like Show a