Frames.Categorical

Support for representing so-called categorical variables: a (usually small) finite set of textual values. We map these onto regular Haskell data types and offer help to generate useful type class instances for such types.

Documentation

newtype Categorical (n :: Nat)

A categorical variable can take on one of a finite number of textual names. Any value of type Categorical n has no more than n variants.

Constructors

Categorical

Fields

• categories :: Set Text

Instances

Eq (Categorical n)

Defined in Frames.Categorical

Methods

(==) :: Categorical n -> Categorical n -> Bool

(/=) :: Categorical n -> Categorical n -> Bool

Show (Categorical n)

Defined in Frames.Categorical

Methods

showsPrec :: Int -> Categorical n -> ShowS

show :: Categorical n -> String

showList :: [Categorical n] -> ShowS

KnownNat n => Parseable (Categorical n)

Defined in Frames.Categorical

Methods

parse :: MonadPlus m => Text -> m (Parsed (Categorical n))

parseCombine :: MonadPlus m => Parsed (Categorical n) -> Parsed (Categorical n) -> m (Parsed (Categorical n))

representableAsType :: Parsed (Categorical n) -> Const (Either (String -> Q [Dec]) Type) (Categorical n)

cap :: String -> String

Ensure the first character of a String is uppercase.

unboxDecls :: String -> Int -> DecsQ

Helper for working with derivingUnbox. Takes the name of the type and the number of variants in the sum type in order to determine a compact representation.

declareCategorical :: String -> Maybe String -> [String] -> Q [Dec]

Generate a splice with data type declaration and associated instances for type suitable for representing a categorical variable. This is a type that maps between a finite set of textual names and Haskell data constructors. Usage: declareCategorical typeName optionalConPrefix variantNames will produce a data type with name typeName and data constructors whose names are a concatenation of optionalConPrefix and each element of variantNames.