| Safe Haskell | Safe |
|---|---|
| Language | Haskell2010 |
Precursor.Algebra.Enum
Contents
Enum class
Class Enum defines operations on sequentially ordered types.
The enumFrom... methods are used in Haskell's translation of
arithmetic sequences.
Instances of Enum may be derived for any enumeration type (types
whose constructors have no fields). The nullary constructors are
assumed to be numbered left-to-right by fromEnum from 0 through n-1.
See Chapter 10 of the Haskell Report for more details.
For any type that is an instance of class Bounded as well as Enum,
the following should hold:
- The calls
succmaxBoundpredminBound fromEnumandtoEnumshould give a runtime error if the result value is not representable in the result type. For example,toEnum7 ::BoolenumFromandenumFromThenshould be defined with an implicit bound, thus:
enumFrom x = enumFromTo x maxBound
enumFromThen x y = enumFromThenTo x y bound
where
bound | fromEnum y >= fromEnum x = maxBound
| otherwise = minBoundMethods
the successor of a value. For numeric types, succ adds 1.
the predecessor of a value. For numeric types, pred subtracts 1.
Convert from an Int.
Convert to an Int.
It is implementation-dependent what fromEnum returns when
applied to a value that is too large to fit in an Int.
Used in Haskell's translation of [n..].
enumFromThen :: a -> a -> [a] #
Used in Haskell's translation of [n,n'..].
enumFromTo :: a -> a -> [a] #
Used in Haskell's translation of [n..m].
enumFromThenTo :: a -> a -> a -> [a] #
Used in Haskell's translation of [n,n'..m].
Instances
| Enum Bool | |
| Enum Char | |
| Enum Int | |
| Enum Int8 | |
| Enum Int16 | |
| Enum Int32 | |
| Enum Int64 | |
| Enum Integer | |
| Enum Ordering | |
| Enum Word | |
| Enum Word8 | |
| Enum Word16 | |
| Enum Word32 | |
| Enum Word64 | |
| Enum () | |
| Enum Associativity | |
| Enum SourceUnpackedness | |
| Enum SourceStrictness | |
| Enum DecidedStrictness | |
| Enum Extension | |
| Enum GenTextMethods | |
| Integral a => Enum (Ratio a) | |
| Enum a => Enum (Identity a) | |
| Enum a => Enum (Min a) | |
| Enum a => Enum (Max a) | |
| Enum a => Enum (First a) | |
| Enum a => Enum (Last a) | |
| Enum a => Enum (WrappedMonoid a) | |
| Enum (Proxy k s) | |
| Enum a => Enum (Const k a b) | |
| Enum (f a) => Enum (Alt k f a) | |
| (~) k a b => Enum ((:~:) k a b) | |
| Enum a => Enum (Tagged k s a) | |
enumFromThen :: Enum a => a -> a -> [a] #
Used in Haskell's translation of [n,n'..].
enumFromTo :: Enum a => a -> a -> [a] #
Used in Haskell's translation of [n..m].
enumFromThenTo :: Enum a => a -> a -> a -> [a] #
Used in Haskell's translation of [n,n'..m].
Bounded class
The Bounded class is used to name the upper and lower limits of a
type. Ord is not a superclass of Bounded since types that are not
totally ordered may also have upper and lower bounds.
The Bounded class may be derived for any enumeration type;
minBound is the first constructor listed in the data declaration
and maxBound is the last.
Bounded may also be derived for single-constructor datatypes whose
constituent types are in Bounded.
Instances