1{- git-annex deferred parse values 2 - 3 - Copyright 2015-2021 Joey Hess <id@joeyh.name> 4 - 5 - Licensed under the GNU AGPL version 3 or higher. 6 -} 7 8{-# LANGUAGE FlexibleInstances #-} 9 10module Types.DeferredParse where 11 12import Annex 13 14import Options.Applicative 15import qualified Data.Semigroup as Sem 16import Prelude 17 18-- Some values cannot be fully parsed without performing an action. 19-- The action may be expensive, so it's best to call finishParse on such a 20-- value before using getParsed repeatedly. 21data DeferredParse a = DeferredParse (Annex a) | ReadyParse a 22 23class DeferredParseClass a where 24 finishParse :: a -> Annex a 25 26getParsed :: DeferredParse a -> Annex a 27getParsed (DeferredParse a) = a 28getParsed (ReadyParse a) = pure a 29 30instance DeferredParseClass (DeferredParse a) where 31 finishParse (DeferredParse a) = ReadyParse <$> a 32 finishParse (ReadyParse a) = pure (ReadyParse a) 33 34instance DeferredParseClass (Maybe (DeferredParse a)) where 35 finishParse Nothing = pure Nothing 36 finishParse (Just v) = Just <$> finishParse v 37 38instance DeferredParseClass [DeferredParse a] where 39 finishParse v = mapM finishParse v 40 41type GlobalOption = Parser GlobalSetter 42 43-- Used for global options that can modify Annex state by running 44-- an arbitrary action in it, and can also set up AnnexRead. 45data GlobalSetter = GlobalSetter 46 { annexStateSetter :: Annex () 47 , annexReadSetter :: AnnexRead -> AnnexRead 48 } 49 50instance Sem.Semigroup GlobalSetter where 51 a <> b = GlobalSetter 52 { annexStateSetter = annexStateSetter a >> annexStateSetter b 53 , annexReadSetter = annexReadSetter b . annexReadSetter a 54 } 55 56instance Monoid GlobalSetter where 57 mempty = GlobalSetter (return ()) id 58