Ordering newtypes for Range.

Range deliberately has no Ord instance because there is no single natural ordering — the right choice depends on the use case. This module provides two explicit wrappers:

• KeyRange — a consistent structural ordering, suitable for use as a Map key or in a Set.
• SortedRange — a positional ordering by location on the number line, suitable for sorting ranges for display.

Example: Map keyed on ranges

import Data.Range (Range, (+=+), lbi)
import Data.Range.Ord (KeyRange(..))
import qualified Data.Map.Strict as Map

type RuleMap = Map (KeyRange Integer) String

rules :: RuleMap
rules = Map.fromList
  [ (KeyRange (1 +=+ 10),  "low")
  , (KeyRange (11 +=+ 50), "medium")
  , (KeyRange (lbi 51),    "high")
  ]

Example: sorting ranges by position on the number line

import Data.List (sortOn)
import Data.Range (Range, (+=+), lbi, ube)
import Data.Range.Ord (SortedRange(..))

sortOn SortedRange [lbi 10, 1 +=+ 5, ube 0 :: Range Integer]
-- [ube 0, 1 +=+ 5, lbi 10]

-- or equivalently:
displayRanges :: Ord a => [Range a] -> [Range a]
displayRanges = sortOn SortedRange

Use KeyRange when you need Range values as Map keys or in a Set. The ordering is consistent but not semantically meaningful on the number line.

Use SortedRange when you want to sort ranges by where they sit on the number line (lower bound first, upper bound as tiebreaker).