{-
Copyright 2016, Dominic Orchard, Andrew Rice, Mistral Contrastin, Matthew Danish
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
-}
{-# LANGUAGE TypeOperators #-}
{-# LANGUAGE PolyKinds #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE CPP #-}
module Camfort.Helpers where
import GHC.Generics
import Data.Generics.Zipper
import Data.Generics.Aliases
import Data.Generics.Str
import Data.Generics.Uniplate.Operations
import Data.Data
import Data.Maybe
import Data.Monoid
import Data.List (elemIndices, group, sort, nub)
import qualified Data.ByteString.Char8 as B
import System.Directory
import Data.List (union)
import qualified Data.Map.Lazy as Map hiding (map, (\\))
import Control.Monad.Writer.Strict
-- collect: from an association list to a map with list-based bins for matching keys
collect :: (Eq a, Ord k) => [(k, a)] -> Map.Map k [a]
collect = Map.fromListWith union . map (fmap (:[]))
type Filename = String
type Directory = String
type SourceText = B.ByteString
type FileOrDir = String
-- Filename and directory related helpers
-- gets the directory part of a filename
getDir :: String -> String
getDir file = let ixs = elemIndices '/' file
in if null ixs then file
else take (last $ ixs) file
{-| Creates a directory (from a filename string) if it doesn't exist -}
checkDir f = case (elemIndices '/' f) of
[] -> return ()
ix -> let d = take (last ix) f
in createDirectoryIfMissing True d
isDirectory :: FileOrDir -> IO Bool
isDirectory s = doesDirectoryExist s
-- Helpers
fanout :: (a -> b) -> (a -> c) -> a -> (b, c)
fanout f g x = (f x, g x)
(<>) :: (a -> b) -> (a -> c) -> a -> (b, c)
f <> g = fanout f g
(><) :: (a -> c) -> (b -> d) -> (a, b) -> (c, d)
f >< g = \(x, y) -> (f x, g y)
-- Lookup functions over relation s
lookups :: Eq a => a -> [(a, b)] -> [b]
lookups _ [] = []
lookups x ((a, b):xs) = if (x == a) then b : lookups x xs
else lookups x xs
lookups' :: Eq a => a -> [((a, b), c)] -> [(b, c)]
lookups' _ [] = []
lookups' x (((a, b), c):xs) = if (x == a) then (b, c) : lookups' x xs
else lookups' x xs
{-| Computes all pairwise combinations -}
pairs :: [a] -> [(a, a)]
pairs [] = []
pairs (x:xs) = (zip (repeat x) xs) ++ (pairs xs)
{-| Functor composed with list functor -}
mfmap :: Functor f => (a -> b) -> [f a] -> [f b]
mfmap f = map (fmap f)
{-| An infix `map` operation.-}
each = flip (map)
{-| Is the Ordering an EQ? -}
cmpEq :: Ordering -> Bool
cmpEq EQ = True
cmpEq _ = False
cmpFst :: (a -> a -> Ordering) -> (a, b) -> (a, b) -> Ordering
cmpFst c (x1, y1) (x2, y2) = c x1 x2
cmpSnd :: (b -> b -> Ordering) -> (a, b) -> (a, b) -> Ordering
cmpSnd c (x1, y1) (x2, y2) = c y1 y2
{-| used for type-level annotations giving documentation -}
type (:?) a (b :: k) = a
-- Helper function, reduces a list two elements at a time with a partial operation
foldPair :: (a -> a -> Maybe a) -> [a] -> [a]
foldPair f [] = []
foldPair f [a] = [a]
foldPair f (a:(b:xs)) = case f a b of
Nothing -> a : (foldPair f (b : xs))
Just c -> foldPair f (c : xs)
class PartialMonoid x where
-- Satisfies equations:
-- pmappend x pmempty = Just x
-- pmappend pempty x = Just x
-- (pmappend y z) >>= (\w -> pmappend x w) = (pmappend x y) >>= (\w -> pmappend w z)
emptyM :: x
appendM :: x -> x -> Maybe x
normalise :: (Ord t, PartialMonoid t) => [t] -> [t]
normalise = nub . reduce . sort
where reduce = foldPair appendM
normaliseNoSort :: (Ord t, PartialMonoid t) => [t] -> [t]
normaliseNoSort = nub . reduce
where reduce = foldPair appendM
normaliseBy :: Ord t => (t -> t -> Maybe t) -> [t] -> [t]
normaliseBy plus = nub . (foldPair plus) . sort
#if __GLASGOW_HASKELL__ < 800
instance Monoid x => Monad ((,) x) where
return a = (mempty, a)
(x, a) >>= k = let (x', b) = k a
in (mappend x x', b)
#endif
-- Data-type generic reduce traversal
reduceCollect :: (Data s, Data t, Uniplate t, Biplate t s) => (s -> Maybe a) -> t -> [a]
reduceCollect k x = execWriter (transformBiM (\y -> do case k y of
Just x -> tell [x]
Nothing -> return ()
return y) x)
-- Data-type generic comonad-style traversal with zipper (contextual traversal)
everywhere :: (Zipper a -> Zipper a) -> Zipper a -> Zipper a
everywhere k z = everywhere' z
where
everywhere' = enterRight . enterDown . k
enterDown z =
case (down' z) of
Just dz -> let dz' = everywhere' dz
in case (up $ dz') of
Just uz -> uz
Nothing -> dz'
Nothing -> z
enterRight z =
case (right z) of
Just rz -> let rz' = everywhere' rz
in case (left $ rz') of
Just lz -> lz
Nothing -> rz'
Nothing -> z
zfmap :: Data a => (a -> a) -> Zipper (d a) -> Zipper (d a)
zfmap f x = zeverywhere (mkT f) x