Hoogle Search

Within LTS Haskell 24.6 (ghc-9.10.2)

Note that Stackage only displays results for the latest LTS and Nightly snapshot. Learn more.

  1. deriveListableCascading :: Name -> DecsQ

    leancheck Test.LeanCheck.Error

    Derives a Listable instance for a given type Name cascading derivation of type arguments as well. Consider the following series of datatypes: 

    data Position  =  CEO | Manager | Programmer

data Person  =  Person
{  name :: String
,  age :: Int
,  position :: Position
}

data Company  =  Company
{  name :: String
,  employees :: [Person]
}
    Writing 
    deriveListableCascading ''Company
    will automatically derive the following three Listable instances: 
    instance Listable Position where
tiers  =  cons0 CEO \/ cons0 Manager \/ cons0 Programmer

instance Listable Person where
tiers  =  cons3 Person

instance Listable Company where
tiers  =  cons2 Company

  2. deriveArgDict :: Name -> Q [Dec]

    constraints-extras Data.Constraint.Extras.TH

    No documentation available.

  3. deriveArgDictV :: Name -> Q [Dec]

    constraints-extras Data.Constraint.Extras.TH

    Deprecated: Just use deriveArgDict

  4. deriveGeneric :: Name -> Q [Dec]

    generics-sop Generics.SOP.TH

    Generate generics-sop boilerplate for the given datatype. This function takes the name of a datatype and generates:

    Note that the generated code will require the TypeFamilies and DataKinds extensions to be enabled for the module. Example: If you have the datatype 
    data Tree = Leaf Int | Node Tree Tree
    and say 
    deriveGeneric ''Tree
    then you get code that is equivalent to: 
    instance Generic Tree where

type Code Tree = '[ '[Int], '[Tree, Tree] ]

from (Leaf x)   = SOP (   Z (I x :* Nil))
from (Node l r) = SOP (S (Z (I l :* I r :* Nil)))

to (SOP    (Z (I x :* Nil)))         = Leaf x
to (SOP (S (Z (I l :* I r :* Nil)))) = Node l r
to (SOP (S (S x)))                   = x `seq` error "inaccessible"

instance HasDatatypeInfo Tree where
type DatatypeInfoOf Tree =
T.ADT "Main" "Tree"
'[ T.Constructor "Leaf", T.Constructor "Node" ]

datatypeInfo _ =
T.demoteDatatypeInfo (Proxy :: Proxy (DatatypeInfoOf Tree))
    Limitations: Generation does not work for GADTs, for datatypes that involve existential quantification, for datatypes with unboxed fields.

  5. deriveGenericFunctions :: Name -> String -> String -> String -> Q [Dec]

    generics-sop Generics.SOP.TH

    Like deriveGenericOnly, but don't derive class instance, only functions. Example: If you say 

    deriveGenericFunctions ''Tree "TreeCode" "fromTree" "toTree"
    then you get code that is equivalent to: 
    type TreeCode = '[ '[Int], '[Tree, Tree] ]

fromTree :: Tree -> SOP I TreeCode
fromTree (Leaf x)   = SOP (   Z (I x :* Nil))
fromTree (Node l r) = SOP (S (Z (I l :* I r :* Nil)))

toTree :: SOP I TreeCode -> Tree
toTree (SOP    (Z (I x :* Nil)))         = Leaf x
toTree (SOP (S (Z (I l :* I r :* Nil)))) = Node l r
toTree (SOP (S (S x)))                   = x `seq` error "inaccessible"

  6. deriveGenericOnly :: Name -> Q [Dec]

    generics-sop Generics.SOP.TH

    Like deriveGeneric, but omit the HasDatatypeInfo instance.

  7. deriveGenericOnlySubst :: Name -> (Name -> Q Type) -> Q [Dec]

    generics-sop Generics.SOP.TH

    Variant of deriveGenericOnly that allows to restrict the type parameters. Experimental function, exposed primarily for benchmarking.

  8. deriveGenericSubst :: Name -> (Name -> Q Type) -> Q [Dec]

    generics-sop Generics.SOP.TH

    Variant of deriveGeneric that allows to restrict the type parameters. Experimental function, exposed primarily for benchmarking.

  9. deriveMetadataType :: Name -> String -> Q [Dec]

    generics-sop Generics.SOP.TH

    Derive DatatypeInfo type for the type. Example: If you say 

    deriveMetadataType ''Tree "TreeDatatypeInfo"
    then you get code that is equivalent to: 
    type TreeDatatypeInfo =
T.ADT "Main" "Tree"
[ T.Constructor "Leaf", T.Constructor "Node" ]

  10. deriveMetadataValue :: Name -> String -> String -> Q [Dec]

    generics-sop Generics.SOP.TH

    Deprecated: Use deriveMetadataType and demoteDatatypeInfo instead.

Page 9 of many | Previous | Next