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gf-core/src-3.0/GF/Parsing/FCFG/Range.hs

51 lines
1.3 KiB
Haskell

---------------------------------------------------------------------
-- |
-- Maintainer : Krasimir Angelov
-- Stability : (stable)
-- Portability : (portable)
--
-- Definitions of ranges, and operations on ranges
-----------------------------------------------------------------------------
module GF.Parsing.FCFG.Range
( RangeRec, Range(..), makeRange, concatRange, rangeEdge, edgeRange, minRange, maxRange,
) where
-- GF modules
import GF.Formalism.Utilities
import GF.Infra.PrintClass
------------------------------------------------------------
-- ranges as single pairs
type RangeRec = [Range]
data Range = Range {-# UNPACK #-} !Int {-# UNPACK #-} !Int
| EmptyRange
deriving (Eq, Ord)
makeRange :: Int -> Int -> Range
makeRange = Range
concatRange :: Range -> Range -> [Range]
concatRange EmptyRange rng = return rng
concatRange rng EmptyRange = return rng
concatRange (Range i j) (Range j' k) = [Range i k | j==j']
rangeEdge :: a -> Range -> Edge a
rangeEdge a (Range i j) = Edge i j a
edgeRange :: Edge a -> Range
edgeRange (Edge i j _) = Range i j
minRange :: Range -> Int
minRange (Range i j) = i
maxRange :: Range -> Int
maxRange (Range i j) = j
instance Print Range where
prt (Range i j) = "(" ++ show i ++ "-" ++ show j ++ ")"
prt (EmptyRange) = "(?)"