diff --git a/ChangeLog.md b/ChangeLog.md new file mode 100644 --- /dev/null +++ b/ChangeLog.md @@ -0,0 +1,5 @@ +# Revision history for heftia-effects + +## 0.1.0.0 -- 2023-09-18 + +* Initial public release. diff --git a/Example/Continuation/Main.hs b/Example/Continuation/Main.hs new file mode 100644 --- /dev/null +++ b/Example/Continuation/Main.hs @@ -0,0 +1,67 @@ +{-# LANGUAGE TemplateHaskell #-} + +-- This Source Code Form is subject to the terms of the Mozilla Public +-- License, v. 2.0. If a copy of the MPL was not distributed with this +-- file, You can obtain one at https://mozilla.org/MPL/2.0/. + +module Main where + +import Control.Effect.Class (sendIns, type (~>)) +import Control.Effect.Class.Machinery.TH (makeEffectF, makeEffectH) +import Control.Effect.Freer (Fre, interposeK, interpret, runFreerEffects, type (<|)) +import Control.Effect.Heftia (Elaborator, runElaborate) +import Control.Monad.Trans.Heftia.Church (HeftiaChurchT) +import Data.Function ((&)) +import Data.Hefty.Extensible (ExtensibleUnionH) +import Data.Hefty.Union (UnionH (absurdUnionH, (|+:))) + +type ForkID = Int + +class Fork f where + fork :: f ForkID + +makeEffectF ''Fork + +runForkSingle :: Monad m => Fre (ForkI ': r) m ~> Fre r m +runForkSingle = interpret \Fork -> pure 0 + +class DelimitFork f where + delimitFork :: Monoid w => f w -> f w + +makeEffectH ''DelimitFork + +applyDelimitFork :: (ForkI <| es, Monad m) => Int -> Elaborator DelimitForkS (Fre es m) +applyDelimitFork numberOfFork (DelimitFork m) = + m & interposeK pure \k Fork -> do + r <- mapM k [1 .. numberOfFork] + pure $ mconcat r + +{- +-- In the `mconcat` section, we utilize the fact that `w` in `delimitFork` is a `Monoid`. +-- However, `hoistHeftiaEffects` quantifies `w` into any type, so we can't make use of +-- it being a `Monoid`. Thus, writing it this way results in a type error. + +runDelimitFork :: + (ForkI <| es, ForallHFunctor r, Monad m) => + Int -> + Hef (DelimitForkS ': r) (Fre es m) ~> Hef r (Fre es m) +runDelimitFork numberOfFork = + interpretH \(DelimitFork m) -> + ($ m) $ hoistHeftiaEffects $ interposeK pure \k Fork -> do + r <- mapM k [1 .. numberOfFork] + pure $ mconcat r -- Here's where the type error occurs +-} + +main :: IO () +main = + runFreerEffects + . runForkSingle + . runElaborate @_ @HeftiaChurchT @ExtensibleUnionH (applyDelimitFork 4 |+: absurdUnionH) + $ do + sendIns . putStrLn . (("[out of scope] " ++) . show) =<< fork + s <- delimitFork do + fid1 <- fork + fid2 <- fork + sendIns $ putStrLn $ "[delimited continuation of `fork`] Fork ID: " ++ show (fid1, fid2) + pure $ show (fid1, fid2) + sendIns $ putStrLn $ "scope exited. result: " ++ s diff --git a/Example/Logging/Main.hs b/Example/Logging/Main.hs new file mode 100644 --- /dev/null +++ b/Example/Logging/Main.hs @@ -0,0 +1,195 @@ +{-# LANGUAGE OverloadedStrings #-} +{-# LANGUAGE TemplateHaskell #-} + +-- This Source Code Form is subject to the terms of the Mozilla Public +-- License, v. 2.0. If a copy of the MPL was not distributed with this +-- file, You can obtain one at https://mozilla.org/MPL/2.0/. + +module Main where + +import Control.Effect.Class (SendIns (sendIns), type (<:), type (~>)) +import Control.Effect.Class.Machinery.TH (makeEffectF, makeEffectH) +import Control.Effect.Class.Reader (Ask (ask), AskI, Local (local), LocalS) +import Control.Effect.Class.State (State (get), StateI, modify) +import Control.Effect.Freer ( + Fre, + flipFreer, + interpose, + interpret, + interpreted, + liftLower, + raise, + raise2, + runFreerEffects, + subsume, + type (<|), + ) +import Control.Effect.Handler.Heftia.Reader (interpretReader, liftReader) +import Control.Effect.Handler.Heftia.State (evalState) +import Control.Effect.Heftia ( + ForallHFunctor, + Hef, + elaborated, + flipHeftia, + hoistHeftiaEffects, + hoistInterpose, + interpretH, + liftLowerH, + runElaborate, + type (<<|), + ) +import Control.Monad (when) +import Control.Monad.Trans.Heftia.Church (HeftiaChurchT) +import Data.Function ((&)) +import Data.Hefty.Extensible (ExtensibleUnionH) +import Data.Hefty.Union (absurdUnionH, (|+:)) +import Data.Text (Text) +import Data.Text qualified as T +import Data.Text.IO qualified as T +import Data.Time (UTCTime, getCurrentTime) +import Data.Time.Format.ISO8601 (iso8601Show) +import Prelude hiding (log) + +class Log f where + log :: Text -> f () + +makeEffectF ''Log + +logToIO :: (IO <: Fre r m, Monad m) => Fre (LogI ': r) m ~> Fre r m +logToIO = interpret \(Log msg) -> sendIns $ T.putStrLn msg + +class Time f where + currentTime :: f UTCTime + +makeEffectF ''Time + +timeToIO :: (IO <: Fre r m, Monad m) => Fre (TimeI ': r) m ~> Fre r m +timeToIO = interpret \case + CurrentTime -> sendIns getCurrentTime + +logWithTime :: (LogI <| es, Time (Fre es m), Monad m) => Fre es m ~> Fre es m +logWithTime = interpose \(Log msg) -> do + t <- currentTime + log $ "[" <> T.pack (show t) <> "] " <> msg + +-- | An effect that introduces a scope that represents a chunk of logs. +class LogChunk f where + logChunk :: f a -> f a + +makeEffectH ''LogChunk + +-- | Output logs in log chunks as they are. +passthroughLogChunk :: + (Monad m, ForallHFunctor r) => + Hef (LogChunkS ': r) m ~> Hef r m +passthroughLogChunk = interpretH \(LogChunk m) -> m + +-- | Limit the number of logs in a log chunk to the first @n@ logs. +limitLogChunk :: + forall m. + (LogChunk m, Log m, Monad m) => + Int -> + LogChunkS (Fre '[LogI] m) ~> m +limitLogChunk n (LogChunk a) = + logChunk + . interpreted + . evalState 0 + . interpretLog + . flipFreer + . raise + $ a + where + interpretLog :: Fre '[LogI, StateI Int] m ~> Fre '[StateI Int] m + interpretLog = + interpret \(Log msg) -> do + count <- get + when (count <= n) do + liftLower $ + if count == n + then log "LOG OMITTED..." + else log msg + + modify @Int (+ 1) + +class FileSystem f where + mkdir :: FilePath -> f () + writeFS :: FilePath -> String -> f () + +makeEffectF ''FileSystem + +runDummyFS :: (IO <: Fre r m, Monad m) => Fre (FileSystemI ': r) m ~> Fre r m +runDummyFS = interpret \case + Mkdir path -> sendIns $ putStrLn $ " mkdir " <> path + WriteFS path content -> sendIns $ putStrLn $ " writeFS " <> path <> " : " <> content + +-- | Create directories according to the log-chunk structure and save one log in one file. +saveLogChunk :: + forall es es' m. + ( LogChunkS <<| es + , LogI <| es' + , FileSystem (Fre es' m) + , Time (Fre es' m) + , Monad m + , ForallHFunctor es + ) => + Hef (LogChunkS ': es) (Fre (LogI ': es') m) ~> Hef es (Fre (LogI ': es') m) +saveLogChunk = + interpretReader ("./log_chunks/" :: FilePath) + . hoistHeftiaEffects flipFreer + . interpretLogChunk + . hoistHeftiaEffects flipFreer + . flipHeftia + . liftReader + where + interpretLogChunk :: + Hef (LogChunkS ': LocalS FilePath ': es) (Fre (LogI ': AskI FilePath ': es') m) + ~> Hef (LocalS FilePath ': es) (Fre (LogI ': AskI FilePath ': es') m) + interpretLogChunk = + interpretH \(LogChunk a) -> logChunk do + chunkBeginAt <- currentTime & raise2 & liftLowerH + local @FilePath (++ iso8601Show chunkBeginAt ++ "/") do + newLogChunkDir <- ask & liftLowerH + mkdir newLogChunkDir & raise2 & liftLowerH + a & hoistInterpose \(Log msg) -> do + logAt <- currentTime & raise2 + saveDir <- ask + log msg & raise2 + writeFS (saveDir ++ iso8601Show logAt ++ ".log") (show msg) & raise2 + +logs :: (LogChunk m, Log m, IO <: m, Monad m) => m () +logs = + logChunk do + log "foo" + log "bar" + log "baz" + log "qux" + + sendIns $ putStrLn "------" + + logChunk do + log "hoge" + log "piyo" + log "fuga" + log "hogera" + + sendIns $ putStrLn "------" + + log "quux" + log "foobar" + +main :: IO () +main = + runFreerEffects + . logToIO + . timeToIO + . logWithTime + . runDummyFS + . subsume + . elaborated + . passthroughLogChunk + . saveLogChunk + . interpreted + . subsume + . runElaborate @_ @HeftiaChurchT @ExtensibleUnionH + (liftLower . limitLogChunk 2 |+: absurdUnionH) + $ logs diff --git a/Example/Teletype/Main.hs b/Example/Teletype/Main.hs new file mode 100644 --- /dev/null +++ b/Example/Teletype/Main.hs @@ -0,0 +1,47 @@ +{-# LANGUAGE TemplateHaskell #-} + +-- This Source Code Form is subject to the terms of the Mozilla Public +-- License, v. 2.0. If a copy of the MPL was not distributed with this +-- file, You can obtain one at https://mozilla.org/MPL/2.0/. + +{- | +The original of this example can be found at polysemy. + +-} +module Main where + +import Control.Effect.Class (Taggable, getTag, sendIns, tag, type (#), type (<:), type (@#), type (~>)) +import Control.Effect.Class.Machinery.TH (makeEffectF) +import Control.Effect.Freer (Fre, interpose, interpret, runFreerEffects, untag, type (<|)) +import Data.Function ((&)) + +class Teletype f where + readTTY :: f String + writeTTY :: String -> f () + +makeEffectF ''Teletype + +teletypeToIO :: (IO <: Fre es m, Monad m) => Fre (TeletypeI ': es) m ~> Fre es m +teletypeToIO = interpret \case + ReadTTY -> sendIns getLine + WriteTTY msg -> sendIns $ putStrLn msg + +data TTY1 + +echo :: (Teletype (m @# TTY1), Monad m, Taggable m) => m () +echo = do + i <- readTTY & tag @TTY1 + case i of + "" -> pure () + _ -> (writeTTY i & tag @TTY1) >> echo + +strong :: (TeletypeI # TTY1 <| es, Monad m) => Fre es m ~> Fre es m +strong = + interpose @(_ # TTY1) \e -> case getTag e of + ReadTTY -> readTTY & tag @TTY1 + WriteTTY msg -> writeTTY (msg <> "!") & tag @TTY1 + +main :: IO () +main = runFreerEffects $ do + sendIns $ putStrLn "Please enter something..." + teletypeToIO . untag @TTY1 . strong . strong $ echo diff --git a/Example/Writer/Main.hs b/Example/Writer/Main.hs new file mode 100644 --- /dev/null +++ b/Example/Writer/Main.hs @@ -0,0 +1,49 @@ +-- This Source Code Form is subject to the terms of the Mozilla Public +-- License, v. 2.0. If a copy of the MPL was not distributed with this +-- file, You can obtain one at https://mozilla.org/MPL/2.0/. + +module Main where + +import Control.Effect.Class (sendIns, type (~>)) +import Control.Effect.Class.Machinery.HFunctor (HFunctor) +import Control.Effect.Class.Writer (Writer, censor, tell) +import Control.Effect.Freer (runFreerEffects) +import Control.Effect.Handler.Heftia.Writer ( + elaborateWriterT, + elaborateWriterTransactionalT, + interpretTell, + ) +import Control.Effect.Heftia (Elaborator, Hef, runElaborate) +import Data.Hefty.Union (absurdUnionH, (|+:)) + +hello :: (Writer String m, Monad m) => m () +hello = do + tell "Hello" + tell " world!" + +censorHello :: (Writer String m, Monad m) => m () +censorHello = + censor + (\s -> if s == "Hello" then "Goodbye" else s) + hello + +main :: IO () +main = runFreerEffects do + (s :: String, _) <- + interpretTell + . runElaborate' (elaborateWriterT @String) + $ censorHello + + (sTransactional :: String, _) <- + interpretTell + . runElaborate' (elaborateWriterTransactionalT @String) + $ censorHello + + sendIns $ putStrLn $ "Normal: " <> s + sendIns $ putStrLn $ "Transactional: " <> sTransactional + +runElaborate' :: + (HFunctor e, Monad f) => + Elaborator e f -> + Hef '[e] f ~> f +runElaborate' f = runElaborate $ f |+: absurdUnionH diff --git a/LICENSE b/LICENSE new file mode 100644 --- /dev/null +++ b/LICENSE @@ -0,0 +1,373 @@ +Mozilla Public License Version 2.0 +================================== + +1. Definitions +-------------- + +1.1. "Contributor" + means each individual or legal entity that creates, contributes to + the creation of, or owns Covered Software. + +1.2. "Contributor Version" + means the combination of the Contributions of others (if any) used + by a Contributor and that particular Contributor's Contribution. + +1.3. "Contribution" + means Covered Software of a particular Contributor. + +1.4. "Covered Software" + means Source Code Form to which the initial Contributor has attached + the notice in Exhibit A, the Executable Form of such Source Code + Form, and Modifications of such Source Code Form, in each case + including portions thereof. + +1.5. "Incompatible With Secondary Licenses" + means + + (a) that the initial Contributor has attached the notice described + in Exhibit B to the Covered Software; or + + (b) that the Covered Software was made available under the terms of + version 1.1 or earlier of the License, but not also under the + terms of a Secondary License. + +1.6. "Executable Form" + means any form of the work other than Source Code Form. + +1.7. "Larger Work" + means a work that combines Covered Software with other material, in + a separate file or files, that is not Covered Software. + +1.8. "License" + means this document. + +1.9. "Licensable" + means having the right to grant, to the maximum extent possible, + whether at the time of the initial grant or subsequently, any and + all of the rights conveyed by this License. + +1.10. "Modifications" + means any of the following: + + (a) any file in Source Code Form that results from an addition to, + deletion from, or modification of the contents of Covered + Software; or + + (b) any new file in Source Code Form that contains any Covered + Software. + +1.11. "Patent Claims" of a Contributor + means any patent claim(s), including without limitation, method, + process, and apparatus claims, in any patent Licensable by such + Contributor that would be infringed, but for the grant of the + License, by the making, using, selling, offering for sale, having + made, import, or transfer of either its Contributions or its + Contributor Version. + +1.12. "Secondary License" + means either the GNU General Public License, Version 2.0, the GNU + Lesser General Public License, Version 2.1, the GNU Affero General + Public License, Version 3.0, or any later versions of those + licenses. + +1.13. "Source Code Form" + means the form of the work preferred for making modifications. + +1.14. "You" (or "Your") + means an individual or a legal entity exercising rights under this + License. For legal entities, "You" includes any entity that + controls, is controlled by, or is under common control with You. For + purposes of this definition, "control" means (a) the power, direct + or indirect, to cause the direction or management of such entity, + whether by contract or otherwise, or (b) ownership of more than + fifty percent (50%) of the outstanding shares or beneficial + ownership of such entity. + +2. License Grants and Conditions +-------------------------------- + +2.1. Grants + +Each Contributor hereby grants You a world-wide, royalty-free, +non-exclusive license: + +(a) under intellectual property rights (other than patent or trademark) + Licensable by such Contributor to use, reproduce, make available, + modify, display, perform, distribute, and otherwise exploit its + Contributions, either on an unmodified basis, with Modifications, or + as part of a Larger Work; and + +(b) under Patent Claims of such Contributor to make, use, sell, offer + for sale, have made, import, and otherwise transfer either its + Contributions or its Contributor Version. + +2.2. Effective Date + +The licenses granted in Section 2.1 with respect to any Contribution +become effective for each Contribution on the date the Contributor first +distributes such Contribution. + +2.3. Limitations on Grant Scope + +The licenses granted in this Section 2 are the only rights granted under +this License. No additional rights or licenses will be implied from the +distribution or licensing of Covered Software under this License. +Notwithstanding Section 2.1(b) above, no patent license is granted by a +Contributor: + +(a) for any code that a Contributor has removed from Covered Software; + or + +(b) for infringements caused by: (i) Your and any other third party's + modifications of Covered Software, or (ii) the combination of its + Contributions with other software (except as part of its Contributor + Version); or + +(c) under Patent Claims infringed by Covered Software in the absence of + its Contributions. + +This License does not grant any rights in the trademarks, service marks, +or logos of any Contributor (except as may be necessary to comply with +the notice requirements in Section 3.4). + +2.4. Subsequent Licenses + +No Contributor makes additional grants as a result of Your choice to +distribute the Covered Software under a subsequent version of this +License (see Section 10.2) or under the terms of a Secondary License (if +permitted under the terms of Section 3.3). + +2.5. Representation + +Each Contributor represents that the Contributor believes its +Contributions are its original creation(s) or it has sufficient rights +to grant the rights to its Contributions conveyed by this License. + +2.6. Fair Use + +This License is not intended to limit any rights You have under +applicable copyright doctrines of fair use, fair dealing, or other +equivalents. + +2.7. Conditions + +Sections 3.1, 3.2, 3.3, and 3.4 are conditions of the licenses granted +in Section 2.1. + +3. Responsibilities +------------------- + +3.1. Distribution of Source Form + +All distribution of Covered Software in Source Code Form, including any +Modifications that You create or to which You contribute, must be under +the terms of this License. You must inform recipients that the Source +Code Form of the Covered Software is governed by the terms of this +License, and how they can obtain a copy of this License. You may not +attempt to alter or restrict the recipients' rights in the Source Code +Form. + +3.2. Distribution of Executable Form + +If You distribute Covered Software in Executable Form then: + +(a) such Covered Software must also be made available in Source Code + Form, as described in Section 3.1, and You must inform recipients of + the Executable Form how they can obtain a copy of such Source Code + Form by reasonable means in a timely manner, at a charge no more + than the cost of distribution to the recipient; and + +(b) You may distribute such Executable Form under the terms of this + License, or sublicense it under different terms, provided that the + license for the Executable Form does not attempt to limit or alter + the recipients' rights in the Source Code Form under this License. + +3.3. Distribution of a Larger Work + +You may create and distribute a Larger Work under terms of Your choice, +provided that You also comply with the requirements of this License for +the Covered Software. If the Larger Work is a combination of Covered +Software with a work governed by one or more Secondary Licenses, and the +Covered Software is not Incompatible With Secondary Licenses, this +License permits You to additionally distribute such Covered Software +under the terms of such Secondary License(s), so that the recipient of +the Larger Work may, at their option, further distribute the Covered +Software under the terms of either this License or such Secondary +License(s). + +3.4. Notices + +You may not remove or alter the substance of any license notices +(including copyright notices, patent notices, disclaimers of warranty, +or limitations of liability) contained within the Source Code Form of +the Covered Software, except that You may alter any license notices to +the extent required to remedy known factual inaccuracies. + +3.5. Application of Additional Terms + +You may choose to offer, and to charge a fee for, warranty, support, +indemnity or liability obligations to one or more recipients of Covered +Software. However, You may do so only on Your own behalf, and not on +behalf of any Contributor. You must make it absolutely clear that any +such warranty, support, indemnity, or liability obligation is offered by +You alone, and You hereby agree to indemnify every Contributor for any +liability incurred by such Contributor as a result of warranty, support, +indemnity or liability terms You offer. You may include additional +disclaimers of warranty and limitations of liability specific to any +jurisdiction. + +4. Inability to Comply Due to Statute or Regulation +--------------------------------------------------- + +If it is impossible for You to comply with any of the terms of this +License with respect to some or all of the Covered Software due to +statute, judicial order, or regulation then You must: (a) comply with +the terms of this License to the maximum extent possible; and (b) +describe the limitations and the code they affect. Such description must +be placed in a text file included with all distributions of the Covered +Software under this License. Except to the extent prohibited by statute +or regulation, such description must be sufficiently detailed for a +recipient of ordinary skill to be able to understand it. + +5. Termination +-------------- + +5.1. The rights granted under this License will terminate automatically +if You fail to comply with any of its terms. However, if You become +compliant, then the rights granted under this License from a particular +Contributor are reinstated (a) provisionally, unless and until such +Contributor explicitly and finally terminates Your grants, and (b) on an +ongoing basis, if such Contributor fails to notify You of the +non-compliance by some reasonable means prior to 60 days after You have +come back into compliance. Moreover, Your grants from a particular +Contributor are reinstated on an ongoing basis if such Contributor +notifies You of the non-compliance by some reasonable means, this is the +first time You have received notice of non-compliance with this License +from such Contributor, and You become compliant prior to 30 days after +Your receipt of the notice. + +5.2. If You initiate litigation against any entity by asserting a patent +infringement claim (excluding declaratory judgment actions, +counter-claims, and cross-claims) alleging that a Contributor Version +directly or indirectly infringes any patent, then the rights granted to +You by any and all Contributors for the Covered Software under Section +2.1 of this License shall terminate. + +5.3. In the event of termination under Sections 5.1 or 5.2 above, all +end user license agreements (excluding distributors and resellers) which +have been validly granted by You or Your distributors under this License +prior to termination shall survive termination. + +************************************************************************ +* * +* 6. Disclaimer of Warranty * +* ------------------------- * +* * +* Covered Software is provided under this License on an "as is" * +* basis, without warranty of any kind, either expressed, implied, or * +* statutory, including, without limitation, warranties that the * +* Covered Software is free of defects, merchantable, fit for a * +* particular purpose or non-infringing. The entire risk as to the * +* quality and performance of the Covered Software is with You. * +* Should any Covered Software prove defective in any respect, You * +* (not any Contributor) assume the cost of any necessary servicing, * +* repair, or correction. This disclaimer of warranty constitutes an * +* essential part of this License. No use of any Covered Software is * +* authorized under this License except under this disclaimer. * +* * +************************************************************************ + +************************************************************************ +* * +* 7. Limitation of Liability * +* -------------------------- * +* * +* Under no circumstances and under no legal theory, whether tort * +* (including negligence), contract, or otherwise, shall any * +* Contributor, or anyone who distributes Covered Software as * +* permitted above, be liable to You for any direct, indirect, * +* special, incidental, or consequential damages of any character * +* including, without limitation, damages for lost profits, loss of * +* goodwill, work stoppage, computer failure or malfunction, or any * +* and all other commercial damages or losses, even if such party * +* shall have been informed of the possibility of such damages. This * +* limitation of liability shall not apply to liability for death or * +* personal injury resulting from such party's negligence to the * +* extent applicable law prohibits such limitation. Some * +* jurisdictions do not allow the exclusion or limitation of * +* incidental or consequential damages, so this exclusion and * +* limitation may not apply to You. * +* * +************************************************************************ + +8. Litigation +------------- + +Any litigation relating to this License may be brought only in the +courts of a jurisdiction where the defendant maintains its principal +place of business and such litigation shall be governed by laws of that +jurisdiction, without reference to its conflict-of-law provisions. +Nothing in this Section shall prevent a party's ability to bring +cross-claims or counter-claims. + +9. Miscellaneous +---------------- + +This License represents the complete agreement concerning the subject +matter hereof. If any provision of this License is held to be +unenforceable, such provision shall be reformed only to the extent +necessary to make it enforceable. Any law or regulation which provides +that the language of a contract shall be construed against the drafter +shall not be used to construe this License against a Contributor. + +10. Versions of the License +--------------------------- + +10.1. New Versions + +Mozilla Foundation is the license steward. Except as provided in Section +10.3, no one other than the license steward has the right to modify or +publish new versions of this License. Each version will be given a +distinguishing version number. + +10.2. Effect of New Versions + +You may distribute the Covered Software under the terms of the version +of the License under which You originally received the Covered Software, +or under the terms of any subsequent version published by the license +steward. + +10.3. Modified Versions + +If you create software not governed by this License, and you want to +create a new license for such software, you may create and use a +modified version of this License if you rename the license and remove +any references to the name of the license steward (except to note that +such modified license differs from this License). + +10.4. Distributing Source Code Form that is Incompatible With Secondary +Licenses + +If You choose to distribute Source Code Form that is Incompatible With +Secondary Licenses under the terms of this version of the License, the +notice described in Exhibit B of this License must be attached. + +Exhibit A - Source Code Form License Notice +------------------------------------------- + + This Source Code Form is subject to the terms of the Mozilla Public + License, v. 2.0. If a copy of the MPL was not distributed with this + file, You can obtain one at https://mozilla.org/MPL/2.0/. + +If it is not possible or desirable to put the notice in a particular +file, then You may include the notice in a location (such as a LICENSE +file in a relevant directory) where a recipient would be likely to look +for such a notice. + +You may add additional accurate notices of copyright ownership. + +Exhibit B - "Incompatible With Secondary Licenses" Notice +--------------------------------------------------------- + + This Source Code Form is "Incompatible With Secondary Licenses", as + defined by the Mozilla Public License, v. 2.0. diff --git a/NOTICE b/NOTICE new file mode 100644 --- /dev/null +++ b/NOTICE @@ -0,0 +1,7 @@ +NOTICE +====== + +Unless explicitly stated otherwise, all Source Code Forms +(recursively, including under subdirectories) contained in the directory +where this NOTICE file is located are subject to the terms of the +Mozilla Public License, v. 2.0. diff --git a/README.md b/README.md new file mode 100644 --- /dev/null +++ b/README.md @@ -0,0 +1,95 @@ +# Heftia +Heftia, a composition of hefty trees and co-Yoneda, is a higher-order effects +version of Freer. + +The paper +* Casper Bach Poulsen and Cas van der Rest. 2023. Hefty Algebras: Modular + Elaboration of Higher-Order Algebraic Effects. Proc. ACM Program. Lang. 7, + POPL, Article 62 (January 2023), 31 pages. + +inspires this library. +Hefty trees, proposed by the above paper, are extensions of free monads, +allowing for a straightforward treatment of higher-order effects. + +This library offers Heftia monads and Freer monads, encoded into data +types in several ways to enable tuning in pursuit of high performance. + +Additionally, it's designed to operate as a handler system based +on [`classy-effects`](https://github.com/sayo-hs/classy-effects), which aims to +standardize and unify the definitions of effects in Haskell. + +Compared to existing Effect System libraries in Haskell that handle higher-order effects, this +library's approach allows for a more effortless and flexible handling of higher-order effects. Here +are some examples: + +* Two interpretations of the `censor` effect for Writer + + Let's consider the following Writer effectful program: + + ```hs + hello :: (Writer String m, Monad m) => m () + hello = do + tell "Hello" + tell " world!" + + censorHello :: (Writer String m, Monad m) => m () + censorHello = + censor + (\s -> if s == "Hello" then "Goodbye" else s) + hello + ``` + + For `censorHello`, should the final written string be `"Goodbye world!"`? Or should it be `"Hello world!"`? + With Heftia, you can freely choose either behavior depending on which higher-order effect interpreter (which we call an elaborator) you use. + + ```hs + main :: IO () + main = runFreerEffects do + (s :: String, _) <- + interpretTell + . runElaborate' (elaborateWriterT @String) + $ censorHello + + (sTransactional :: String, _) <- + interpretTell + . runElaborate' (elaborateWriterTransactionalT @String) + $ censorHello + + sendIns $ putStrLn $ "Normal: " <> s + sendIns $ putStrLn $ "Transactional: " <> sTransactional + ``` + + Using the `elaborateWriterT` elaborator, you'll get "Goodbye world!", whereas with the `elaborateWriterTransactionalT` elaborator, you'll get "Hello world!". + For more details, please refer to the [complete code](https://github.com/sayo-hs/heftia/blob/master/heftia-effects/Example/Writer/Main.hs) and the [implementation of the elaborator](https://github.com/sayo-hs/heftia/blob/master/heftia-effects/src/Control/Effect/Handler/Heftia/Writer.hs). + +* Extracting Multi-shot Delimited Continuations + + In handling higher-order effects, it's easy to work with multi-shot delimited continuations. + This enables an almost complete emulation of "Algebraic Effects and Handlers". + For more details, please refer to + [Example 3 - Delimited Continuation]() . + +Furthermore, the structure of Heftia is theoretically straightforward, with ad-hoc elements being +eliminated. + +Heftia is the second objective of the [Sayo Project](https://github.com/sayo-hs). + +## Documentation +Examples with explanations can be found in the [docs/examples/](https://github.com/sayo-hs/heftia/tree/master/docs/examples) directory. + +## Future Plans +* Benchmarking +* Enriching the documentation +* Completing missing definitions such as + * the Heftia monad transformer encoded in tree structure + * handlers for the `Accum`, `Coroutine`, `Fresh`, `Input`, `Output` effect classes + + and others. + +## License +The license is MPL 2.0. Please refer to the [NOTICE](https://github.com/sayo-hs/heftia/blob/master/NOTICE). +Additionally, this README.md and the documents under the `docs`/`docs-ja` directory are licensed +under CC BY-SA 4.0. + +## Your contributions are welcome! +Please see [CONTRIBUTING.md](https://github.com/sayo-hs/heftia/blob/master/CONTRIBUTING.md). diff --git a/heftia-effects.cabal b/heftia-effects.cabal new file mode 100644 --- /dev/null +++ b/heftia-effects.cabal @@ -0,0 +1,150 @@ +cabal-version: 2.4 +name: heftia-effects +version: 0.1.0.0 + +-- A short (one-line) description of the package. +synopsis: Handlers for standard effects using Heftia. + +-- A longer description of the package. +description: + This library provides interpreters based + on [Heftia](https://hackage.haskell.org/package/heftia) for the standard effect classes + compliant with [CEPs](https://github.com/sayo-hs/classy-effects/blob/master/CEPs/README.md), + offered by + the [classy-effects](https://hackage.haskell.org/package/classy-effects) package. + +-- A URL where users can report bugs. +bug-reports: https://github.com/sayo-hs/heftia + +-- The license under which the package is released. +license: MPL-2.0 +license-file: LICENSE +author: Yamada Ryo +maintainer: Yamada Ryo + +-- A copyright notice. +copyright: 2023 Yamada Ryo +category: Control, Effect, Monads + +extra-source-files: + ChangeLog.md + NOTICE + README.md + +tested-with: + GHC == 9.2.8 + +source-repository head + type: git + location: https://github.com/sayo-hs/heftia + tag: v0.1.0 + subdir: heftia-effects + +common common-base + ghc-options: -Wall + default-language: GHC2021 + + default-extensions: + LambdaCase, + DerivingStrategies, + DataKinds, + TypeFamilies, + BlockArguments, + FunctionalDependencies, + RecordWildCards, + DefaultSignatures, + PatternSynonyms + +library + import: common-base + + exposed-modules: + Control.Effect.Handler.Heftia.Reader + Control.Effect.Handler.Heftia.Writer + Control.Effect.Handler.Heftia.State + Control.Effect.Handler.Heftia.Except + Control.Effect.Handler.Heftia.Provider + + -- Modules included in this executable, other than Main. + -- other-modules: + + -- LANGUAGE extensions used by modules in this package. + -- other-extensions: + build-depends: + base ^>= 4.16.4.0, + heftia ^>= 0.1, + classy-effects ^>= 0.1, + mtl ^>= 2.2.2, + transformers ^>= 0.5.6, + extensible ^>= 0.9, + + hs-source-dirs: src + +test-suite test + import: common-base + + main-is: Driver.hs + hs-source-dirs: test + build-depends: + heftia-effects, + classy-effects, + heftia, + base, + tasty ^>= 1.4, + tasty-hunit ^>= 0.10, + + build-tool-depends: + tasty-discover:tasty-discover + + type: exitcode-stdio-1.0 + + +executable Teletype + import: common-base + + main-is: Main.hs + hs-source-dirs: Example/Teletype + build-depends: + classy-effects, + heftia, + heftia-effects, + base, + +executable Logging + import: common-base + + main-is: Main.hs + hs-source-dirs: Example/Logging + ghc-options: -Wall -fplugin GHC.TypeLits.KnownNat.Solver + build-depends: + classy-effects, + heftia, + heftia-effects, + base, + text ^>= 1.2.5, + time ^>= 1.11.1, + loglevel ^>= 0.1.0, + extra ^>= 1.7.14, + ghc-typelits-knownnat ^>= 0.7, + +executable Continuation + import: common-base + + main-is: Main.hs + hs-source-dirs: Example/Continuation + build-depends: + classy-effects, + heftia, + heftia-effects, + base, + +executable Writer + import: common-base + + main-is: Main.hs + hs-source-dirs: Example/Writer + build-depends: + classy-effects, + heftia, + heftia-effects, + base, diff --git a/src/Control/Effect/Handler/Heftia/Except.hs b/src/Control/Effect/Handler/Heftia/Except.hs new file mode 100644 --- /dev/null +++ b/src/Control/Effect/Handler/Heftia/Except.hs @@ -0,0 +1,52 @@ +-- This Source Code Form is subject to the terms of the Mozilla Public +-- License, v. 2.0. If a copy of the MPL was not distributed with this +-- file, You can obtain one at https://mozilla.org/MPL/2.0/. + +{- | +Copyright : (c) 2023 Yamada Ryo +License : MPL-2.0 (see the file LICENSE) +Maintainer : ymdfield@outlook.jp +Stability : experimental +Portability : portable + +Interpreter and elaborator for the t'Control.Effect.Class.Except.Except' effect class. +-} +module Control.Effect.Handler.Heftia.Except where + +import Control.Effect.Class (type (~>)) +import Control.Effect.Class.Except (CatchS (Catch), ThrowI (Throw)) +import Control.Effect.Freer (Fre, interposeK, interposeT, interpretK, interpretT, type (<|)) +import Control.Monad.Trans.Except (ExceptT (ExceptT), runExceptT, throwE) +import Data.Function ((&)) + +-- | Elaborate the 'Catch' effect using the 'ExceptT' monad transformer. +elaborateExceptT :: + (ThrowI e <| es, Monad m) => + CatchS e (Fre es m) ~> Fre es m +elaborateExceptT (Catch action (hdl :: e -> Fre es m a)) = do + r <- runExceptT $ action & interposeT \(Throw (e :: e)) -> throwE e + case r of + Left e -> hdl e + Right a -> pure a + +{- | +Elaborate the 'Catch' effect using the t'Control.Monad.Trans.Cont.ContT' continuation monad +transformer. +-} +elaborateExceptK :: + (ThrowI e <| es, Monad m) => + CatchS e (Fre es m) ~> Fre es m +elaborateExceptK (Catch action (hdl :: e -> Fre es m a)) = + action & interposeK pure \_ (Throw (e :: e)) -> hdl e + +-- | Interpret the 'Throw' effect using the 'ExceptT' monad transformer. +interpretThrowT :: Monad m => Fre (ThrowI e ': es) m ~> ExceptT e (Fre es m) +interpretThrowT = interpretT \(Throw e) -> throwE e +{-# INLINE interpretThrowT #-} + +{- | +Interpret the 'Throw' effect using the t'Control.Monad.Trans.Cont.ContT' continuation monad +transformer. +-} +interpretThrowK :: Monad m => Fre (ThrowI e ': es) m a -> Fre es m (Either e a) +interpretThrowK = interpretK (pure . Right) \_ (Throw e) -> pure $ Left e diff --git a/src/Control/Effect/Handler/Heftia/Provider.hs b/src/Control/Effect/Handler/Heftia/Provider.hs new file mode 100644 --- /dev/null +++ b/src/Control/Effect/Handler/Heftia/Provider.hs @@ -0,0 +1,39 @@ +-- This Source Code Form is subject to the terms of the Mozilla Public +-- License, v. 2.0. If a copy of the MPL was not distributed with this +-- file, You can obtain one at https://mozilla.org/MPL/2.0/. + +{- | +Copyright : (c) 2023 Yamada Ryo +License : MPL-2.0 (see the file LICENSE) +Maintainer : ymdfield@outlook.jp +Stability : experimental +Portability : portable + +Elaborator for the t'Control.Effect.Class.Provider.Provider' effect class. +-} +module Control.Effect.Handler.Heftia.Provider where + +import Control.Effect.Class (type (~>)) +import Control.Effect.Class.Provider (ProviderS (Provide)) +import Control.Effect.Heftia (Elaborator) +import Control.Monad.Trans (MonadTrans, lift) + +-- | Elaborate the t'Control.Effect.Class.Provider.Provider' effect using the given interpreter. +elaborateProvider :: + (c h, e h) => + (f ~> h) -> + (forall x. i -> h x -> f (g x)) -> + Elaborator (ProviderS c e i g) f +elaborateProvider iLower run (Provide i a) = run i $ a iLower +{-# INLINE elaborateProvider #-} + +{- | +Elaborate the t'Control.Effect.Class.Provider.Provider' effect using the given interpreter for some +monad transformer. +-} +elaborateProviderT :: + (Monad m, MonadTrans t, c (t m), e (t m)) => + (forall x. i -> t m x -> m (g x)) -> + Elaborator (ProviderS c e i g) m +elaborateProviderT = elaborateProvider lift +{-# INLINE elaborateProviderT #-} diff --git a/src/Control/Effect/Handler/Heftia/Reader.hs b/src/Control/Effect/Handler/Heftia/Reader.hs new file mode 100644 --- /dev/null +++ b/src/Control/Effect/Handler/Heftia/Reader.hs @@ -0,0 +1,50 @@ +-- This Source Code Form is subject to the terms of the Mozilla Public +-- License, v. 2.0. If a copy of the MPL was not distributed with this +-- file, You can obtain one at https://mozilla.org/MPL/2.0/. + +{- | +Copyright : (c) 2023 Yamada Ryo +License : MPL-2.0 (see the file LICENSE) +Maintainer : ymdfield@outlook.jp +Stability : experimental +Portability : portable + +Interpreter and elaborator for the t'Control.Effect.Class.Reader.Reader' effect class. +-} +module Control.Effect.Handler.Heftia.Reader where + +import Control.Effect.Class (type (~>)) +import Control.Effect.Class.Reader (AskI (Ask), LocalS (Local), ask) +import Control.Effect.Freer (Fre, interpose, interpret, raise, type (<|)) +import Control.Effect.Heftia (ForallHFunctor, Hef, hoistHeftiaEffects, hoistInterpose, interpretH, raiseH) +import Data.Function ((&)) + +interpretReader :: + (Monad m, ForallHFunctor es) => + r -> + Hef (LocalS r ': es) (Fre (AskI r ': es') m) ~> Hef es (Fre es' m) +interpretReader r = hoistHeftiaEffects (interpretAsk r) . interpretReaderH +{-# INLINE interpretReader #-} + +interpretReaderH :: + (AskI r <| es', ForallHFunctor es, Monad m) => + Hef (LocalS r ': es) (Fre es' m) ~> Hef es (Fre es' m) +interpretReaderH = + interpretH \(Local (f :: r -> r) a) -> + a & hoistInterpose @(AskI r) \Ask -> f <$> ask + +elaborateReader :: + (AskI r <| es, Monad m) => + LocalS r (Fre es m) ~> Fre es m +elaborateReader (Local (f :: r -> r) a) = + a & interpose @(AskI r) \Ask -> f <$> ask + +interpretAsk :: Monad m => r -> Fre (AskI r ': es) m ~> Fre es m +interpretAsk r = interpret \Ask -> pure r +{-# INLINE interpretAsk #-} + +liftReader :: + (ForallHFunctor es, Monad m) => + Hef es (Fre es' m) ~> Hef (LocalS FilePath ': es) (Fre (AskI FilePath ': es') m) +liftReader = raiseH . hoistHeftiaEffects raise +{-# INLINE liftReader #-} diff --git a/src/Control/Effect/Handler/Heftia/State.hs b/src/Control/Effect/Handler/Heftia/State.hs new file mode 100644 --- /dev/null +++ b/src/Control/Effect/Handler/Heftia/State.hs @@ -0,0 +1,42 @@ +-- This Source Code Form is subject to the terms of the Mozilla Public +-- License, v. 2.0. If a copy of the MPL was not distributed with this +-- file, You can obtain one at https://mozilla.org/MPL/2.0/. + +{- | +Copyright : (c) 2023 Yamada Ryo +License : MPL-2.0 (see the file LICENSE) +Maintainer : ymdfield@outlook.jp +Stability : experimental +Portability : portable + +Interpreter for the t'Control.Effect.Class.State.State' effect class. +-} +module Control.Effect.Handler.Heftia.State where + +import Control.Effect.Class (type (~>)) +import Control.Effect.Class.State (StateI (Get, Put)) +import Control.Effect.Freer (Fre, interpretT) +import Control.Monad.State (StateT) +import Control.Monad.Trans.State (runStateT) +import Control.Monad.Trans.State qualified as T +import Data.Tuple (swap) + +-- | Interpret the 'Get'/'Put' effects using the 'StateT' monad transformer. +interpretState :: forall s es m a. Monad m => s -> Fre (StateI s ': es) m a -> Fre es m (s, a) +interpretState s a = swap <$> runStateT (interpretStateT a) s +{-# INLINE interpretState #-} + +evalState :: forall s es m a. Monad m => s -> Fre (StateI s ': es) m a -> Fre es m a +evalState s a = snd <$> interpretState s a +{-# INLINE evalState #-} + +execState :: forall s es m a. Monad m => s -> Fre (StateI s ': es) m a -> Fre es m s +execState s a = fst <$> interpretState s a +{-# INLINE execState #-} + +-- | Interpret the 'Get'/'Put' effects using the 'StateT' monad transformer. +interpretStateT :: forall s es m. Monad m => Fre (StateI s ': es) m ~> StateT s (Fre es m) +interpretStateT = interpretT \case + Get -> T.get + Put s -> T.put s +{-# INLINE interpretStateT #-} diff --git a/src/Control/Effect/Handler/Heftia/Writer.hs b/src/Control/Effect/Handler/Heftia/Writer.hs new file mode 100644 --- /dev/null +++ b/src/Control/Effect/Handler/Heftia/Writer.hs @@ -0,0 +1,76 @@ +{-# LANGUAGE AllowAmbiguousTypes #-} + +-- This Source Code Form is subject to the terms of the Mozilla Public +-- License, v. 2.0. If a copy of the MPL was not distributed with this +-- file, You can obtain one at https://mozilla.org/MPL/2.0/. + +{- | +Copyright : (c) 2023 Yamada Ryo +License : MPL-2.0 (see the file LICENSE) +Maintainer : ymdfield@outlook.jp +Stability : experimental +Portability : portable + +Interpreter and elaborator for the t'Control.Effect.Class.Writer.Writer' effect class. +See [README.md](https://github.com/sayo-hs/heftia/blob/master/README.md). +-} +module Control.Effect.Handler.Heftia.Writer where + +import Control.Effect.Class (type (~>)) +import Control.Effect.Class.Writer (Tell (tell), TellI (Tell), WriterS (Censor, Listen)) +import Control.Effect.Freer (Fre, intercept, interposeT, interpretK, interpretT, type (<|)) +import Control.Monad.Trans.Writer.CPS (WriterT, runWriterT) +import Control.Monad.Trans.Writer.CPS qualified as T +import Data.Function ((&)) +import Data.Tuple (swap) + +elaborateWriterT :: + forall w m es. + (Monad m, Monoid w, TellI w <| es) => + WriterS w (Fre es m) ~> Fre es m +elaborateWriterT = \case + Listen m -> listenT m + Censor f m -> m & intercept @(TellI w) \(Tell w) -> Tell $ f w + +elaborateWriterTransactionalT :: + forall w m es. + (Monad m, Monoid w, TellI w <| es) => + WriterS w (Fre es m) ~> Fre es m +elaborateWriterTransactionalT = \case + Listen m -> listenT m + Censor f m -> do + (a, w) <- confiscateT m + tell $ f w + pure a + +listenT :: + (Monoid w, Monad m, TellI w <| es) => + Fre es m a -> + Fre es m (a, w) +listenT m = do + (a, w) <- confiscateT m + tell w + pure (a, w) +{-# INLINE listenT #-} + +confiscateT :: + forall w m es a. + (Monoid w, Monad m, TellI w <| es) => + Fre es m a -> + Fre es m (a, w) +confiscateT = runWriterT . interposeT @(TellI w) \(Tell w) -> T.tell w +{-# INLINE confiscateT #-} + +interpretTell :: (Monad m, Monoid w) => Fre (TellI w ': es) m a -> Fre es m (w, a) +interpretTell = fmap swap . runWriterT . interpretTellT +{-# INLINE interpretTell #-} + +interpretTellT :: (Monad m, Monoid w) => Fre (TellI w ': es) m a -> WriterT w (Fre es m) a +interpretTellT = interpretT \(Tell w) -> T.tell w +{-# INLINE interpretTellT #-} + +interpretTellK :: (Monad m, Monoid w) => Fre (TellI w ': es) m a -> Fre es m (w, a) +interpretTellK = + interpretK (pure . (mempty,)) \k (Tell w) -> do + (w', r) <- k () + pure (w <> w', r) diff --git a/test/Driver.hs b/test/Driver.hs new file mode 100644 --- /dev/null +++ b/test/Driver.hs @@ -0,0 +1,5 @@ +{-# OPTIONS_GHC -F -pgmF tasty-discover #-} + +-- This Source Code Form is subject to the terms of the Mozilla Public +-- License, v. 2.0. If a copy of the MPL was not distributed with this +-- file, You can obtain one at https://mozilla.org/MPL/2.0/.