mirror of
https://github.com/github/semantic.git
synced 2024-12-22 06:11:49 +03:00
66 lines
1.8 KiB
Haskell
66 lines
1.8 KiB
Haskell
module Diff where
|
|
|
|
{-# LANGUAGE DeriveFunctor #-}
|
|
|
|
import Data.Maybe
|
|
|
|
data Free f a = Pure a | Roll (f (Free f a))
|
|
deriving Functor
|
|
newtype Fix f = In { out :: f (Fix f) }
|
|
data Cofree f a = Unroll a (f (Cofree f a))
|
|
deriving Functor
|
|
|
|
data Range = Range { start :: Int, end :: Int }
|
|
|
|
type Info = String
|
|
|
|
type Term a = Fix (Syntax a)
|
|
data Patch a = Patch { old :: Maybe a, new :: Maybe a }
|
|
type Diff a = Free (Syntax a) (Patch (Term a))
|
|
|
|
(</>) :: Maybe (Term a) -> Maybe (Term a) -> Diff a
|
|
(</>) a b = Pure $ Patch { old = a, new = b }
|
|
|
|
a :: Term String
|
|
a = In $ Keyed [
|
|
("hello", In $ Indexed [ In $ Leaf "hi" ]),
|
|
("goodbye", In $ Leaf "goodbye") ]
|
|
|
|
b :: Term String
|
|
b = In $ Keyed [
|
|
("hello", In $ Indexed []),
|
|
("goodbye", In $ Indexed []) ]
|
|
|
|
d :: Diff String
|
|
d = Roll $ Keyed [
|
|
("hello", Roll $ Indexed [ Just (In $ Leaf "hi") </> Nothing ]),
|
|
("goodbye", Just (In $ Leaf "goodbye") </> Just (In $ Indexed [])) ]
|
|
|
|
data Operation a f
|
|
= Recur (Term a) (Term a) (Diff a -> f)
|
|
| ByKey [(String, Term a)] [(String, Term a)] ([(String, Diff a)] -> f)
|
|
| ByIndex [Term a] [Term a] ([Diff a] -> f)
|
|
|
|
type Algorithm a = Free (Operation a)
|
|
|
|
iter :: Functor f => (f a -> a) -> Free f a -> a
|
|
iter _ (Pure a) = a
|
|
iter phi (Roll m) = phi $ iter phi <$> m
|
|
|
|
cost :: Diff a -> Integer
|
|
cost f = iter c $ fmap g f where
|
|
c (Leaf _) = 0
|
|
c (Keyed xs) = sum $ snd <$> xs
|
|
c (Indexed xs) = sum xs
|
|
g _ = 1
|
|
|
|
-- interpret :: Algorithm a b -> b
|
|
-- interpret (Pure b) = b
|
|
-- interpret (Roll (Recur a b f)) = f $ Pure (Patch { old = Just (In a), new = Just (In b) })
|
|
|
|
type RangedTerm a = Cofree (Syntax a) Int
|
|
-- data Difff a f = Difff (Either (Patch (Term a)) (Syntax a f))
|
|
-- type RangedDiff a = Cofree (Difff a) Range
|
|
data AnnotatedSyntax a f = AnnotatedSyntax (Range, Syntax a f)
|
|
type RangedDiff a = Free (AnnotatedSyntax a) (Patch (Term a))
|