never executed always true always false

    1 module Reporting.Region where
    2 
    3 import Prelude ()
    4 import Relude
    5 
    6 import Text.Show (showParen, showString, showsPrec)
    7 
    8 import qualified Data.String as String
    9 import qualified Text.Parsec.Pos as Parsec
   10 
   11 
   12 data Region = Region
   13     { start :: Position
   14     , end :: Position
   15     }
   16     deriving (Eq)
   17 
   18 
   19 instance Show Region where
   20     showsPrec p r = showParen (p > 10) $
   21         showString $ String.unwords
   22             [ "at"
   23             , show (line $ start r)
   24             , show (column $ start r)
   25             , show (line $ end r)
   26             , show (column $ end r) 
   27             ]
   28 
   29 
   30 data Position = Position
   31     { line :: Int
   32     , column :: Int
   33     }
   34     deriving (Eq, Show)
   35 
   36 
   37 fromSourcePos :: Parsec.SourcePos -> Position
   38 fromSourcePos sourcePos =
   39     Position
   40       (Parsec.sourceLine sourcePos)
   41       (Parsec.sourceColumn sourcePos)
   42 
   43 
   44 merge :: Region -> Region -> Region
   45 merge (Region start _) (Region _ end) =
   46     Region start end
   47 
   48 
   49 -- TO STRING
   50 
   51 toString :: Region -> String
   52 toString (Region start end) =
   53   case line start == line end of
   54     False ->
   55         "between lines " ++ show (line start)
   56         ++ " and " ++ show (line end)
   57 
   58     True ->
   59         "on line " ++ show (line end) ++ ", column "
   60         ++ show (column start) ++ " to " ++ show (column end)