never executed always true always false

    1 module HelVM.HelIO.Containers.MTInsertDef where
    2 
    3 import           Control.Type.Operator
    4 
    5 import           Data.Default
    6 import           Data.MonoTraversable
    7 import           Data.Sequence         ((|>))
    8 import           Data.Sequences
    9 
   10 import qualified Data.IntMap           as IntMap
   11 import qualified Data.Sequence         as Seq
   12 
   13 -- | Insert a new element
   14 naturalInsertDef :: (InsertDef seq , Num $ Index seq) => Natural -> Element seq -> seq -> seq
   15 naturalInsertDef = insertDef <$> fromIntegral
   16 
   17 -- | Type Class
   18 class InsertDef seq where
   19   insertDef :: Index seq -> Element seq -> seq -> seq
   20 
   21 instance Default a => InsertDef [a] where
   22   insertDef 0 e []     = [e]
   23   insertDef 0 e (_:xs) = e   : xs
   24   insertDef i e []     = def : insertDef (i-1) e []
   25   insertDef i e (x:xs) = x   : insertDef (i-1) e xs
   26 
   27 instance Default a => InsertDef (Seq a) where
   28   insertDef i e c = (check <$> Seq.length) c where
   29     check l
   30       | i < l       = Seq.update i e c
   31       | otherwise   = c <> Seq.replicate (i - l) def |> e
   32 
   33 instance Index (IntMap a) ~ Int => InsertDef (IntMap a) where
   34   insertDef = IntMap.insert