Copyright | (c) The University of Glasgow 2001 |
---|---|
License | BSD-style (see the file libraries/base/LICENSE) |
Maintainer | libraries@haskell.org |
Stability | stable |
Portability | portable |
Safe Haskell | Trustworthy |
Language | Haskell2010 |
The Ix
class
class Ord a => Ix a where Source
The Ix
class is used to map a contiguous subrange of values in
a type onto integers. It is used primarily for array indexing
(see the array package).
The first argument (l,u)
of each of these operations is a pair
specifying the lower and upper bounds of a contiguous subrange of values.
An implementation is entitled to assume the following laws about these operations:
The list of values in the subrange defined by a bounding pair.
index :: (a, a) -> a -> Int Source
The position of a subscript in the subrange.
inRange :: (a, a) -> a -> Bool Source
Returns True
the given subscript lies in the range defined
the bounding pair.
rangeSize :: (a, a) -> Int Source
The size of the subrange defined by a bounding pair.
Ix Bool Source | |
Ix Char Source | |
Ix Int Source | |
Ix Int8 Source | |
Ix Int16 Source | |
Ix Int32 Source | |
Ix Int64 Source | |
Ix Integer Source | |
Ix Ordering Source | |
Ix Word Source | |
Ix Word8 Source | |
Ix Word16 Source | |
Ix Word32 Source | |
Ix Word64 Source | |
Ix () Source | |
Ix GeneralCategory Source | |
Ix SeekMode Source | |
Ix IOMode Source | |
Ix Natural Source | |
Ix Void Source | |
(Ix a, Ix b) => Ix (a, b) Source | |
Ix (Proxy k s) Source | |
(Ix a1, Ix a2, Ix a3) => Ix (a1, a2, a3) Source | |
(Ix a1, Ix a2, Ix a3, Ix a4) => Ix (a1, a2, a3, a4) Source | |
(Ix a1, Ix a2, Ix a3, Ix a4, Ix a5) => Ix (a1, a2, a3, a4, a5) Source | |
Deriving Instances of Ix
Derived instance declarations for the class Ix
are only possible
for enumerations (i.e. datatypes having only nullary constructors)
and single-constructor datatypes, including arbitrarily large tuples,
whose constituent types are instances of Ix
.
- For an enumeration, the nullary constructors are assumed to be
numbered left-to-right with the indices being 0 to n-1 inclusive. This
is the same numbering defined by the
Enum
class. For example, given the datatype:
data Colour = Red | Orange | Yellow | Green | Blue | Indigo | Violet
we would have:
range (Yellow,Blue) == [Yellow,Green,Blue] index (Yellow,Blue) Green == 1 inRange (Yellow,Blue) Red == False
- For single-constructor datatypes, the derived instance declarations are as shown for tuples in chapter 19, section 2 of the Haskell 2010 report: https://www.haskell.org/onlinereport/haskell2010/haskellch19.html.