Adding stacks and queues

Author: Divesh-Otwani

linear-base.cabal

@@ -58,7 +58,9 @@ library
     Data.Ord.Linear.Internal.Eq
     Data.Profunctor.Kleisli.Linear
     Data.Profunctor.Linear
+    Data.Queue.Mutable.Linear
     Data.Set.Mutable.Linear
+    Data.Stack.Mutable.Linear
     Data.Tuple.Linear
     Data.Unrestricted.Internal.Consumable
     Data.Unrestricted.Internal.Dupable

src/Data/Deque/Mutable/Linear.hs

@@ -19,7 +19,6 @@ module Data.Deque.Mutable.Linear
   , alloc
   , fromList
   -- * Querying
-  , size
   , length
   , peekFront
   , peekBack
@@ -86,7 +85,7 @@ nextPtr sz (Ptr p) = (p + 1) `mod` sz
 -- # Allocation
 -------------------------------------------------------------------------------
 
--- | Run a computation of an empty Deque with a given size
+-- | Run a computation of an empty Deque with a given initial allocated size
 alloc :: Int -> (Deque a %1-> Ur b) %1-> Ur b
 alloc k f = Array.alloc k err $ \arr -> f (Deque 0 0 arr) where
   err = Prelude.error "Accessing error element of a collection!"

src/Data/Queue/Mutable/Linear.hs

@@ -0,0 +1,78 @@
+{-# LANGUAGE GADTs #-}
+{-# LANGUAGE LinearTypes #-}
+{-# LANGUAGE NoImplicitPrelude #-}
+
+-- | Mutable linear queues
+--
+-- This module provides mutable queues with a pure API. Import thusly:
+--
+-- > import qualified Data.Queue.Mutable.Linear as Linear
+--
+module Data.Queue.Mutable.Linear
+  (
+  -- * Construction
+    Queue
+  , alloc
+  , fromList
+  -- * Modification
+  , push
+  , pop
+  , map
+  -- * Querying
+  , top
+  , length
+  -- * Consumption
+  , toList
+  )
+where
+
+import Data.Deque.Mutable.Linear (Deque)
+import qualified Data.Deque.Mutable.Linear as Deque
+import qualified Data.Functor.Linear as Data
+import Data.Unrestricted.Linear
+import Prelude.Linear hiding (length, map)
+
+
+-- # API
+-------------------------------------------------------------------------------
+
+data Queue a where
+  Queue :: {-# UNPACK #-} !(Deque a) %1-> Queue a
+  -- We represent a queue as a Deque where we add to the front end
+  -- and take from the back end
+
+unqueue :: Queue a %1-> Deque a
+unqueue (Queue deq) = deq
+
+-- | Allocate a queue with a given initial allocated size
+alloc :: Int -> (Queue a %1-> Ur b) %1-> Ur b
+alloc k f = Deque.alloc k $ \deq -> f (Queue deq)
+
+-- | Given a list, make a queue where we treat the end of the list
+-- as the top of the queue, the first-in-line element
+fromList :: [a] -> (Queue a %1-> Ur b) %1-> Ur b
+fromList xs f = Deque.fromList xs $ \deq -> f (Queue deq)
+
+push :: a -> Queue a %1-> Queue a
+push x = Queue . Deque.pushFront x . unqueue
+
+pop :: Queue a %1-> (Ur (Maybe a), Queue a)
+pop = Data.fmap Queue . Deque.popBack . unqueue
+
+map :: (a -> b) -> Queue a %1-> Queue b
+map f = Queue . Deque.map f . unqueue
+
+top :: Queue a %1-> (Ur (Maybe a), Queue a)
+top = Data.fmap Queue . Deque.peekBack . unqueue
+
+length :: Queue a %1-> (Ur Int, Queue a)
+length = Data.fmap Queue . Deque.length . unqueue
+
+-- | Convert to a list where the head of the
+-- list is the top of the stack
+toList :: Queue a %1-> Ur [a]
+toList = Deque.toList . unqueue
+
+instance Consumable (Queue a) where
+  consume (Queue deq) = consume deq
+

src/Data/Stack/Mutable/Linear.hs

@@ -0,0 +1,78 @@
+{-# LANGUAGE GADTs #-}
+{-# LANGUAGE LinearTypes #-}
+{-# LANGUAGE NoImplicitPrelude #-}
+
+-- | Mutable linear stacks
+--
+-- This module provides mutable stacks with a pure API. Import thusly:
+--
+-- > import qualified Data.Stack.Mutable.Linear as Linear
+--
+module Data.Stack.Mutable.Linear
+  (
+  -- * Construction
+    Stack
+  , alloc
+  , fromList
+  -- * Modification
+  , push
+  , pop
+  , map
+  -- * Querying
+  , top
+  , length
+  -- * Consumption
+  , toList
+  )
+where
+
+import Data.Deque.Mutable.Linear (Deque)
+import qualified Data.Deque.Mutable.Linear as Deque
+import qualified Data.Functor.Linear as Data
+import Data.Unrestricted.Linear
+import Prelude.Linear hiding (length, map)
+
+
+-- # API
+-------------------------------------------------------------------------------
+
+data Stack a where
+  Stack :: {-# UNPACK #-} !(Deque a) %1-> Stack a
+  -- We represent a stack as a Deque where we grow and
+  -- shrink from the **front** end
+
+unstack :: Stack a %1-> Deque a
+unstack (Stack deq) = deq
+
+-- | Allocate a stack with a given initial allocated size
+alloc :: Int -> (Stack a %1-> Ur b) %1-> Ur b
+alloc k f = Deque.alloc k $ \deq -> f (Stack deq)
+
+-- | Given a list, make a stack where we treat the head of the list
+-- as the top of the stack
+fromList :: [a] -> (Stack a %1-> Ur b) %1-> Ur b
+fromList xs f = Deque.fromList xs $ \deq -> f (Stack deq)
+
+push :: a -> Stack a %1-> Stack a
+push x = Stack . Deque.pushFront x . unstack
+
+pop :: Stack a %1-> (Ur (Maybe a), Stack a)
+pop = Data.fmap Stack . Deque.popFront . unstack
+
+map :: (a -> b) -> Stack a %1-> Stack b
+map f = Stack . Deque.map f . unstack
+
+top :: Stack a %1-> (Ur (Maybe a), Stack a)
+top = Data.fmap Stack . Deque.peekFront . unstack
+
+length :: Stack a %1-> (Ur Int, Stack a)
+length = Data.fmap Stack . Deque.length . unstack
+
+-- | Convert to a list where the head of the
+-- list is the top of the stack
+toList :: Stack a %1-> Ur [a]
+toList = Deque.toList . unstack
+
+instance Consumable (Stack a) where
+  consume (Stack deq) = consume deq
+