diff --git a/ChangeLog.md b/ChangeLog.md new file mode 100644 --- /dev/null +++ b/ChangeLog.md @@ -0,0 +1,7 @@ +# Changelog for free-category + +## Version 0.0.1.0 +- free category (concrete and condensity transformed) +- free arrows (concrete and condensity transformed) + +## Unreleased changes 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 http://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/README.md b/README.md new file mode 100644 --- /dev/null +++ b/README.md @@ -0,0 +1,13 @@ +# Free Category +[![Maintainer: coot](https://img.shields.io/badge/maintainer-coot-lightgrey.svg)](http://github.com/coot) +[![Travis Build Status](https://travis-ci.org/coot/free-category.svg?branch=master)](https://travis-ci.org/coot/free-category) + +This package introduces variouos encodings of free categories in Haskell. + +Free categories are useful to model state machines in a simple yet type safe +way and for that purpose `Kleisli` categroies are a very useful target which +allows to include monadic computations. Read more +[here](https://coot.me/posts/finite-state-machines.html) on a simple example of +a finite state machine encoded using a free category using a simple GADT. +Another simple +[example](https://github.com/coot/free-algebras/blob/master/examples/src/Control/Category/Free.hs). diff --git a/Setup.hs b/Setup.hs new file mode 100644 --- /dev/null +++ b/Setup.hs @@ -0,0 +1,2 @@ +import Distribution.Simple +main = defaultMain diff --git a/free-category.cabal b/free-category.cabal new file mode 100644 --- /dev/null +++ b/free-category.cabal @@ -0,0 +1,58 @@ +name: free-category +version: 0.0.1.0 +synopsis: Free category +description: Free categories +category: Algebra, Control, Monads, Category +homepage: https://github.com/coot/free-category#readme +bug-reports: https://github.com/coot/free-category/issues +author: Marcin Szamotulski +maintainer: profunctor@pm.me +copyright: (c) 2018 Marcin Szamotulski +license: MPL-2.0 +license-file: LICENSE +build-type: Simple +cabal-version: >= 1.10 +extra-source-files: + ChangeLog.md + README.md + +source-repository head + type: git + location: https://github.com/coot/free-category + +library + exposed-modules: + Control.Arrow.Free + Control.Category.Free + other-modules: + Paths_free_category + hs-source-dirs: + src + default-extensions: + ConstraintKinds + DataKinds + DeriveFunctor + EmptyDataDecls + FlexibleInstances + FlexibleContexts + GADTs + KindSignatures + InstanceSigs + MultiParamTypeClasses + OverloadedStrings + PolyKinds + RankNTypes + ScopedTypeVariables + TupleSections + TypeApplications + TypeFamilies + build-depends: + base >= 4.9 && <5 + , free-algebras >= 0.0.6.0 + ghc-options: + -Wall + -fwarn-incomplete-record-updates + -fwarn-incomplete-uni-patterns + -fwarn-redundant-constraints + -fwarn-deprecations + default-language: Haskell2010 diff --git a/src/Control/Arrow/Free.hs b/src/Control/Arrow/Free.hs new file mode 100644 --- /dev/null +++ b/src/Control/Arrow/Free.hs @@ -0,0 +1,111 @@ +{-# LANGUAGE GADTs #-} +module Control.Arrow.Free + ( -- * Free arrow + Arr (..) + -- * Free arrow (CPS style) + , A (..) + , fromA + , toA + -- * Free interface re-exports + , FreeAlgebra2 (..) + , wrapFree2 + , foldFree2 + , hoistFree2 + , joinFree2 + , bindFree2 + ) where + +import Prelude hiding (id, (.)) +import Control.Arrow (Arrow (..)) +import Control.Category (Category (..)) +import Control.Algebra.Free2 + ( AlgebraType0 + , AlgebraType + , FreeAlgebra2 (..) + , proof + , wrapFree2 + , foldFree2 + , hoistFree2 + , hoistFreeH2 + , joinFree2 + , bindFree2 + ) + +data Arr f a b where + Id :: Arr f a a + (:.:) :: f b c -> Arr f a b -> Arr f a c + Arr :: (b -> c) -> Arr f a b -> Arr f a c + Prod :: Arr f a b -> Arr f a c -> Arr f a (b, c) + +instance Category (Arr f) where + id = Id + Id . f = f + f . Id = f + (f :.: g) . h = f :.: (g . h) + (Arr f g) . h = Arr f (g . h) + (Prod f g) . h = Prod (f . h) (g . h) + +instance Arrow (Arr f) where + arr f = Arr f Id + first bc = Prod (bc . arr fst) (arr snd) + second bc = Prod (arr fst) (bc . arr snd) + ab *** xy = Prod (ab . arr fst) (xy . arr snd) + (&&&) = Prod + +type instance AlgebraType0 Arr f = () +type instance AlgebraType Arr c = Arrow c + +instance FreeAlgebra2 Arr where + liftFree2 = \fab -> fab :.: Id + {-# INLINE liftFree2 #-} + + foldNatFree2 _ Id = id + foldNatFree2 fun (bc :.: ab) = fun bc . foldNatFree2 fun ab + foldNatFree2 fun (Arr f g) = arr f . foldNatFree2 fun g + foldNatFree2 fun (Prod f g) = foldNatFree2 fun f &&& foldNatFree2 fun g + {-# INLINE foldNatFree2 #-} + + codom2 = proof + forget2 = proof + +newtype A f a b + = A { runA :: forall r. Arrow r + => (forall x y. f x y -> r x y) + -> r a b + } + +-- | +-- Isomorphism from @'Arr'@ to @'A'@, which is a specialisation of +-- @'hoistFreeH2'@. +toA :: Arr f a b -> A f a b +toA = hoistFreeH2 +{-# INLINE toA #-} + +-- | +-- Inverse of @'fromA'@, which also is a specialisatin of @'hoistFreeH2'@. +fromA :: A f a b -> Arr f a b +fromA = hoistFreeH2 +{-# INLINE fromA #-} + +instance Category (A f) where + id = A (const id) + A f . A g = A $ \k -> f k . g k + +instance Arrow (A f) where + arr f = A (const (arr f)) + A f *** A g = A $ \k -> f k *** g k + first (A f) = A $ \k -> first (f k) + second (A f) = A $ \k -> second (f k) + +type instance AlgebraType0 A f = () +type instance AlgebraType A c = Arrow c + +instance FreeAlgebra2 A where + liftFree2 = \fab -> A $ \k -> k fab + {-# INLINE liftFree2 #-} + + foldNatFree2 fun (A f) = f fun + {-# INLINE foldNatFree2 #-} + + codom2 = proof + forget2 = proof diff --git a/src/Control/Category/Free.hs b/src/Control/Category/Free.hs new file mode 100644 --- /dev/null +++ b/src/Control/Category/Free.hs @@ -0,0 +1,178 @@ +{-# LANGUAGE CPP #-} +{-# LANGUAGE StandaloneDeriving #-} +module Control.Category.Free + ( -- * Free category + Cat (..) + -- * Free category (CPS style) + , C (..) + , toC + , fromC + + -- * Free interface re-exports + , FreeAlgebra2 (..) + , wrapFree2 + , foldFree2 + , hoistFree2 + , joinFree2 + , bindFree2 + ) + where + +import Prelude hiding (id, (.)) +import Control.Category (Category (..)) +import Control.Algebra.Free2 + ( AlgebraType0 + , AlgebraType + , FreeAlgebra2 (..) + , proof + , wrapFree2 + , foldFree2 + , hoistFree2 + , hoistFreeH2 + , joinFree2 + , bindFree2 + ) +import Control.Arrow (Arrow (..), ArrowZero (..), ArrowChoice (..)) +#if __GLASGOW_HASKELL__ < 804 +import Data.Monoid (Monoid (..)) +import Data.Semigroup (Semigroup (..)) +#endif +import Data.Monoid.MSet (MSet (..)) +import Data.Semigroup.SSet (SSet (..)) + +-- | +-- Free category encoded as a recursive data type, in a simlar way as +-- @'Control.Monad.Free.Free'@. You can use @'FreeAlgebra2'@ class instance: +-- +-- prop> liftFree2 @Cat :: f a b -> Cat f ab +-- prop> foldNatFree2 @Cat :: Category d => (forall x y. f x y -> d x y) -> Cat f a b -> d a b +-- +-- The same performance concerns that apply to @'Control.Monad.Free.Free'@ +-- apply to this encoding of a free category. +data Cat :: (* -> * -> *) -> * -> * -> * where + Id :: Cat f a a + (:.:) :: f b c -> Cat f a b -> Cat f a c + +instance Category (Cat f) where + id = Id + Id . ys = ys + (x :.: xs) . ys = x :.: (xs . ys) + +infixr 9 :.: + +instance Arrow f => Arrow (Cat f) where + arr ab = arr ab :.: Id + + Id *** Id = Id + Id *** (fxb :.: cax) = (arr id *** fxb) :.: (Id *** cax) + (fxb :.: cax) *** Id = (fxb *** arr id) :.: (cax *** Id) + (fxb :.: cax) *** (fyb :.: cay) = (fxb *** fyb) :.: (cax *** cay) + +instance ArrowZero f => ArrowZero (Cat f) where + zeroArrow = zeroArrow :.: Id + +instance ArrowChoice f => ArrowChoice (Cat f) where + Id +++ Id = Id + Id +++ (fxb :.: cax) = (arr id +++ fxb) :.: (Id +++ cax) + (fxb :.: cax) +++ Id = (fxb +++ arr id) :.: (cax +++ Id) + (fxb :.: cax) +++ (fyb :.: cay) = (fxb +++ fyb) :.: (cax +++ cay) + +instance Semigroup (Cat f o o) where + f <> g = g . f + +instance Monoid (Cat f o o) where + mempty = Id +#if __GLASGOW_HASKELL__ < 804 + mappend = (<>) +#endif + +instance SSet (Cat f o o) (Cat f a o) where + act = (.) + +instance MSet (Cat f o o) (Cat f a o) where +#if __GLASGOW_HASKELL__ < 804 + mact = (.) +#endif + +type instance AlgebraType0 Cat f = () +type instance AlgebraType Cat c = Category c + +instance FreeAlgebra2 Cat where + liftFree2 = \fab -> fab :.: Id + {-# INLINE liftFree2 #-} + + foldNatFree2 _ Id = id + foldNatFree2 fun (bc :.: ab) = fun bc . foldNatFree2 fun ab + {-# INLINE foldNatFree2 #-} + + codom2 = proof + forget2 = proof + +-- | +-- CPS style encoded free category; one can use @'FreeAlgebra2'@ class +-- instance: +-- +-- prop> liftFree2 @C :: f a b -> C f ab +-- prop> foldNatFree2 @C :: Category d => (forall x y. f x y -> d x y) -> C f a b -> d a b +newtype C f a b + = C { runC :: forall r. Category r + => (forall x y. f x y -> r x y) + -> r a b + } + +instance Category (C f) where + id = C (const id) + C bc . C ab = C $ \k -> bc k . ab k + +-- | +-- Isomorphism from @'Cat'@ to @'C'@, which is a specialisation of +-- @'hoistFreeH2'@. +toC :: Cat f a b -> C f a b +toC = hoistFreeH2 +{-# INLINE toC #-} + +-- | +-- Inverse of @'fromC'@, which also is a specialisatin of @'hoistFreeH2'@. +fromC :: C f a b -> Cat f a b +fromC = hoistFreeH2 +{-# INLINE fromC #-} + +type instance AlgebraType0 C f = () +type instance AlgebraType C c = Category c + +instance FreeAlgebra2 C where + liftFree2 = \fab -> C $ \k -> k fab + {-# INLINE liftFree2 #-} + + foldNatFree2 fun (C f) = f fun + {-# INLINE foldNatFree2 #-} + + codom2 = proof + forget2 = proof + +instance Arrow f => Arrow (C f) where + arr ab = C $ \k -> k (arr ab) + C c1 *** C c2 = C $ \k -> k (c1 id *** c2 id) + +instance ArrowZero f => ArrowZero (C f) where + zeroArrow = C $ \k -> k zeroArrow + +instance ArrowChoice f => ArrowChoice (C f) where + C c1 +++ C c2 = C $ \k -> k (c1 id +++ c2 id) + +instance Semigroup (C f o o) where + f <> g = f . g + +instance Monoid (C f o o) where + mempty = id +#if __GLASGOW_HASKELL__ < 804 + mappend = (<>) +#endif + +instance SSet (C f o o) (C f a o) where + act = (.) + +instance MSet (C f o o) (C f a o) where +#if __GLASGOW_HASKELL__ < 804 + mact = (.) +#endif