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gi-gtk-declarative (empty) → 0.1.0

raw patch · 16 files changed

+1525/−0 lines, 16 filesdep +basedep +gi-gobjectdep +gi-gtksetup-changed

Dependencies added: base, gi-gobject, gi-gtk, haskell-gi, haskell-gi-base, haskell-gi-overloading, mtl, text, unordered-containers

Files

+ CHANGELOG.md view
@@ -0,0 +1,5 @@+* 0.1.0+    - First version of `gi-gtk-declarative`!+    - Basic widget without event handling+    - Support for `Box` and `ScrolledWindow` containers+    - Declarative CSS classes
+ LICENSE view
@@ -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.
+ Setup.hs view
@@ -0,0 +1,2 @@+import Distribution.Simple+main = defaultMain
+ gi-gtk-declarative.cabal view
@@ -0,0 +1,47 @@+name:                 gi-gtk-declarative+version:              0.1.0+synopsis:             Declarative GTK+ programming in Haskell+description:          A declarative programming model for GTK+ user+                      interfaces, implementing support for various widgets+                      and generalized patching. This library aims to extend the+                      gi-gtk library as transparently as possible, and to be+                      a reusable library for multiple application architectures+                      and styles.++                      See [the project README](https://github.com/owickstrom/gi-gtk-declarative#readme)+                      for more information.+license:              MPL-2.0+license-file:         LICENSE+author:               Oskar Wickström+maintainer:           oskar.wickstrom@gmail.com+copyright:            Oskar Wickström+category:             Graphics+build-type:           Simple+cabal-version:        >=1.10+extra-source-files:   CHANGELOG.md++library+  exposed-modules:      GI.Gtk.Declarative+                      , GI.Gtk.Declarative.Attributes+                      , GI.Gtk.Declarative.Attributes.Internal+                      , GI.Gtk.Declarative.Bin+                      , GI.Gtk.Declarative.Container+                      , GI.Gtk.Declarative.Container.Box+                      , GI.Gtk.Declarative.Container.Patch+                      , GI.Gtk.Declarative.CSS+                      , GI.Gtk.Declarative.EventSource+                      , GI.Gtk.Declarative.Markup+                      , GI.Gtk.Declarative.Patch+                      , GI.Gtk.Declarative.SingleWidget+  build-depends:        base >=4.10 && <4.12+                      , gi-gobject             >= 2    && <3+                      , gi-gtk                 >= 3    && <4+                      , haskell-gi             >= 0.21 && <0.22+                      , haskell-gi-base        >= 0.21 && <0.22+                      , haskell-gi-overloading == 1.0+                      , mtl+                      , text+                      , unordered-containers >= 0.2 && < 0.3+  hs-source-dirs:       src+  default-language:     Haskell2010+  ghc-options:          -Wall
+ src/GI/Gtk/Declarative.hs view
@@ -0,0 +1,19 @@+-- | The declarative layer on top of GTK+ lets you describe your user+-- interface as a declarative hierarchy of objects, using data+-- structures and pure functions. You can leverage the declarative event+-- handling to build reusable widgets. The "Patch" typeclass, and the+-- instances provided by this library, performs minimal updates to GTK+ widgets+-- using the underlying imperative operations, so that your rendering can always+-- be a pure function your state to a "Widget".+module GI.Gtk.Declarative+  ( module Export+  ) where++import           GI.Gtk.Declarative.Attributes    as Export+import           GI.Gtk.Declarative.Bin           as Export+import           GI.Gtk.Declarative.Container     as Export+import           GI.Gtk.Declarative.Container.Box as Export+import           GI.Gtk.Declarative.CSS           as Export+import           GI.Gtk.Declarative.Markup        as Export+import           GI.Gtk.Declarative.Patch         as Export+import           GI.Gtk.Declarative.SingleWidget  as Export
+ src/GI/Gtk/Declarative/Attributes.hs view
@@ -0,0 +1,227 @@+{-# LANGUAGE DataKinds              #-}+{-# LANGUAGE FlexibleContexts       #-}+{-# LANGUAGE FlexibleInstances      #-}+{-# LANGUAGE FunctionalDependencies #-}+{-# LANGUAGE GADTs                  #-}+{-# LANGUAGE KindSignatures         #-}+{-# LANGUAGE LambdaCase             #-}+{-# LANGUAGE MultiParamTypeClasses  #-}+{-# LANGUAGE OverloadedLabels       #-}+{-# LANGUAGE RankNTypes             #-}+{-# LANGUAGE ScopedTypeVariables    #-}+{-# LANGUAGE TypeApplications       #-}+{-# LANGUAGE TypeFamilies           #-}+{-# LANGUAGE TypeOperators          #-}++-- | Attribute lists on declarative objects, supporting the underlying+-- attributes from "Data.GI.Base.Attributes", along with CSS class lists, and+-- pure and impure event callbacks.++module GI.Gtk.Declarative.Attributes+  ( Attribute(..)+  -- *+  , classes+  -- * Event Handling+  , on+  , onM+  -- * Callbacks+  , ToGtkCallback(..)+  )+where++import           Control.Monad                  (void)+import qualified Data.GI.Base.Attributes        as GI+import qualified Data.GI.Base.Signals           as GI+import qualified Data.HashSet                   as HashSet+import           Data.Text                      (Text)+import           Data.Typeable+import           GHC.TypeLits                   (KnownSymbol, Symbol)+import qualified GI.Gtk                         as Gtk++import           GI.Gtk.Declarative.CSS++-- * Attributes++-- | The attribute GADT represent a supported attribute for a declarative+-- widget. This extends the regular notion of GTK+ attributes to also include+-- event handling and CSS classes.+data Attribute widget event where+  -- | An attribute/value mapping for a declarative widget. The+  -- 'GI.AttrLabelProxy' is parameterized by 'attr', which represents the+  -- GTK-defined attribute name. The underlying GI object needs to support+  -- the /construct/, /get/, and /set/ operations for the given attribute.+  (:=)+    :: (GI.AttrOpAllowed 'GI.AttrConstruct info widget+      , GI.AttrOpAllowed 'GI.AttrSet info widget+      , GI.AttrGetC info widget attr getValue+      , GI.AttrSetTypeConstraint info setValue+      , KnownSymbol attr+      , Typeable attr+      )+   => GI.AttrLabelProxy (attr :: Symbol) -> setValue -> Attribute widget event+  -- | Defines a set of CSS classes for the underlying widget's style context.+  -- Use the 'classes' function instead of this constructor directly.+  Classes+    :: Gtk.IsWidget widget+    => ClassSet+    -> Attribute widget event+  -- | Emit events using a pure callback. Use the 'on function instead of this+  -- constructor directly.+  OnSignalPure+    :: ( Gtk.GObject widget+       , GI.SignalInfo info+       , callback ~ GI.HaskellCallbackType info+       , Functor (PureCallback callback)+       , ToGtkCallback (PureCallback callback)+       , callback ~ CustomGtkCallback (PureCallback callback)+       )+    => Gtk.SignalProxy widget info+    -> PureCallback callback event+    -> Attribute widget event+  -- | Emit events using an impure callback. Use the 'on function instead of+  -- this constructor directly.+  OnSignalImpure+    :: ( Gtk.GObject widget+       , GI.SignalInfo info+       , callback ~ GI.HaskellCallbackType info+       , Functor (ImpureCallback callback widget)+       , ToGtkCallback (ImpureCallback callback widget)+       , (widget -> callback) ~ CustomGtkCallback (ImpureCallback callback widget)+       )+    => Gtk.SignalProxy widget info+    -> ImpureCallback callback widget event+    -> Attribute widget event++-- | Attributes have a 'Functor' instance that maps events in all event+-- callbacks.+instance Functor (Attribute widget) where+  fmap f = \case+    attr := value -> attr := value+    Classes cs -> Classes cs+    OnSignalPure signal cb -> OnSignalPure signal (fmap f cb)+    OnSignalImpure signal cb -> OnSignalImpure signal (fmap f cb)++-- | Define the CSS classes for the underlying widget's style context. For these+-- classes to have any effect, this requires a 'Gtk.CssProvider' with CSS files+-- loaded, to be added to the GDK screen. You probably want to do this in your+-- entry point when setting up GTK.+classes :: Gtk.IsWidget widget => [Text] -> Attribute widget event+classes = Classes . HashSet.fromList++-- | Emit events, using a pure callback, by subcribing to the specified+-- signal.+on+  :: ( Gtk.GObject widget+     , GI.SignalInfo info+     , callback ~ GI.HaskellCallbackType info+     , pure ~ ToPureCallback callback event+     , Functor (PureCallback callback)+     , ToGtkCallback (PureCallback callback)+     , callback ~ CustomGtkCallback (PureCallback callback)+     )+  => Gtk.SignalProxy widget info+  -> pure+  -> Attribute widget event+on signal = OnSignalPure signal . PureCallback++-- | Emit events, using an impure callback receiving the 'widget' and returning+-- an 'IO' action of 'event', by subcribing to the specified signal.+onM+  :: ( Gtk.GObject widget+     , GI.SignalInfo info+     , callback ~ GI.HaskellCallbackType info+     , impure ~ ToImpureCallback callback event+     , withWidget ~ (widget -> impure)+     , Functor (ImpureCallback callback widget)+     , ToGtkCallback (ImpureCallback callback widget)+     , (widget -> callback) ~ CustomGtkCallback (ImpureCallback callback widget)+     )+  => Gtk.SignalProxy widget info+  -> withWidget+  -> Attribute widget event+onM signal = OnSignalImpure signal . ImpureCallback++-- * Pure Callbacks++-- | Convert a GTK+ callback type to a pure callback type, i.e. a type+-- without 'IO'. The pure callback is either a single 'event', or a function of+-- the same arity and arguments as the GTK+ callback, but with the 'event' as+-- the range.+type family ToPureCallback gtkCallback event where+  ToPureCallback (IO ()) event = event+  ToPureCallback (a -> b) event = a -> ToPureCallback b event++-- | A 'PureCallback' holds a pure callback, as defined by 'ToPureCallback'.+data PureCallback callback event where+  PureCallback+    :: (pure ~ ToPureCallback callback event)+    => pure+    -> PureCallback callback event++-- The functor instances are pretty annoying, being repeated for each function+-- arity. Could this be done in another way?++instance Functor (PureCallback (IO ())) where+  fmap f (PureCallback e) = PureCallback (f e)++instance Functor (PureCallback (x -> IO ())) where+  fmap f (PureCallback g) = PureCallback (f . g)++instance Functor (PureCallback (x -> y -> IO ())) where+  fmap f (PureCallback g) = PureCallback (\x -> f . g x)++-- * Impure Callbacks++-- | Convert a GTK+ callback type to an impure callback type, i.e. a type+-- with 'IO event' as the range, instead of 'IO ()'. The impure callback is+-- either a single 'IO event', or a function of the same arity and arguments as+-- the GTK+ callback, but with 'IO event' as the range.+type family ToImpureCallback t e where+  ToImpureCallback (IO ()) e  = IO e+  ToImpureCallback (a -> b) e = a -> ToImpureCallback b e++-- | An 'ImpureCallback' holds an impure callback, as defined by+-- 'ToImpureCallback', but with an extra 'widget' argument. This is so that+-- impure callbacks can query their underlying GTK+ widgets for data.+data ImpureCallback callback widget event where+  ImpureCallback+    :: (impure ~ ToImpureCallback callback event)+    => (widget -> impure)+    -> ImpureCallback callback widget event++-- The functor instances are pretty annoying, being repeated for each function+-- arity. Could this be done in another way?++instance Functor (ImpureCallback (IO ()) widget) where+  fmap f (ImpureCallback g) = ImpureCallback (\w -> f <$> g w)++instance Functor (ImpureCallback (x -> IO ()) widget) where+  fmap f (ImpureCallback g) = ImpureCallback (\w -> fmap f . g w)++instance Functor (ImpureCallback (x -> y -> IO ()) widget) where+  fmap f (ImpureCallback g) = ImpureCallback (\w x -> fmap f . g w x)++-- * GTK+ Callback Conversions++-- | Internal class for converting user callbacks to gi-gtk callbacks.+class ToGtkCallback userCallback where+  type CustomGtkCallback userCallback :: *+  -- | Converts a user callback, i.e. a pure or an impure callback, back to a+  -- GTK+ callback.+  toGtkCallback :: userCallback event -> (event -> IO ()) -> CustomGtkCallback userCallback++instance ToGtkCallback (PureCallback (IO ())) where+  type CustomGtkCallback (PureCallback (IO ())) = IO ()+  toGtkCallback (PureCallback cb) f = void (f cb)++instance ToGtkCallback (PureCallback (x -> IO ())) where+  type CustomGtkCallback (PureCallback (x -> IO ())) = x -> IO ()+  toGtkCallback (PureCallback cb) f x = void (f (cb x))++instance ToGtkCallback (PureCallback (x -> y -> IO ()))  where+  type CustomGtkCallback (PureCallback (x -> y -> IO ())) = x -> y -> IO ()+  toGtkCallback (PureCallback cb) f x y = void (f (cb x y))++instance ToGtkCallback (ImpureCallback (IO ()) widget)  where+  type CustomGtkCallback (ImpureCallback (IO ()) widget) = widget -> IO ()+  toGtkCallback (ImpureCallback cb) f w = void (cb w >>= f)
+ src/GI/Gtk/Declarative/Attributes/Internal.hs view
@@ -0,0 +1,59 @@+{-# LANGUAGE DataKinds              #-}+{-# LANGUAGE LambdaCase             #-}++-- | Internal helpers for applying attributes and signal handlers to GTK++-- widgets.+module GI.Gtk.Declarative.Attributes.Internal+  ( extractAttrConstructOps+  , extractAttrSetOps+  , addClass+  , removeClass+  , addSignalHandler+  ) where++import qualified Data.GI.Base.Attributes        as GI+import qualified GI.GObject           as GI+import qualified GI.Gtk                         as Gtk+import           Control.Monad.IO.Class         (MonadIO)++import           GI.Gtk.Declarative.Attributes+import           GI.Gtk.Declarative.EventSource++extractAttrConstructOps+  :: Attribute widget event -> [GI.AttrOp widget 'GI.AttrConstruct]+extractAttrConstructOps = \case+  (attr := value) -> pure (attr Gtk.:= value)+  _               -> mempty++extractAttrSetOps :: Attribute widget event -> [GI.AttrOp widget 'GI.AttrSet]+extractAttrSetOps = \case+  (attr := value) -> pure (attr Gtk.:= value)+  _               -> mempty++addClass :: MonadIO m => Gtk.StyleContext -> Attribute widget event -> m ()+addClass sc = \case+  Classes cs -> mapM_ (Gtk.styleContextAddClass sc) cs+  _          -> pure ()++removeClass :: MonadIO m => Gtk.StyleContext -> Attribute widget event -> m ()+removeClass sc = \case+  Classes cs -> mapM_ (Gtk.styleContextRemoveClass sc) cs+  _          -> pure ()++addSignalHandler+  :: (Gtk.IsWidget widget, MonadIO m)+  => (event -> IO ())+  -> widget+  -> Attribute widget event+  -> m (Maybe Subscription)+addSignalHandler onEvent widget' = \case+  OnSignalPure signal handler -> do+    handlerId <- Gtk.on widget' signal (toGtkCallback handler onEvent)+    w         <- Gtk.toWidget widget'+    pure (Just (fromCancellation (GI.signalHandlerDisconnect w handlerId)))+  OnSignalImpure signal handler -> do+    handlerId <- Gtk.on widget' signal (toGtkCallback handler onEvent widget')+    w         <- Gtk.toWidget widget'+    pure (Just (fromCancellation (GI.signalHandlerDisconnect w handlerId)))+  _ -> pure Nothing+
+ src/GI/Gtk/Declarative/Bin.hs view
@@ -0,0 +1,167 @@+{-# OPTIONS_GHC -fno-warn-unticked-promoted-constructors #-}+{-# LANGUAGE DataKinds              #-}+{-# LANGUAGE FlexibleContexts       #-}+{-# LANGUAGE FlexibleInstances      #-}+{-# LANGUAGE FunctionalDependencies #-}+{-# LANGUAGE GADTs                  #-}+{-# LANGUAGE LambdaCase             #-}+{-# LANGUAGE MultiParamTypeClasses  #-}+{-# LANGUAGE OverloadedLabels       #-}+{-# LANGUAGE ScopedTypeVariables    #-}+{-# LANGUAGE TypeFamilies           #-}+{-# LANGUAGE TypeOperators          #-}++-- | A declarative representation of 'Gtk.Bin' in GTK.+module GI.Gtk.Declarative.Bin+  ( Bin+  , bin+  )+where++import           Control.Monad                          ((>=>))+import           Data.Maybe+import           Data.Typeable+import qualified GI.GObject                             as GI+import qualified GI.Gtk                                 as Gtk++import           GI.Gtk.Declarative.Attributes+import           GI.Gtk.Declarative.Attributes.Internal+import           GI.Gtk.Declarative.EventSource+import           GI.Gtk.Declarative.Markup+import           GI.Gtk.Declarative.Patch+++-- | Supported 'Gtk.Bin's.+class BinChild bin (child :: * -> *) | bin -> child where+  getChild :: bin -> IO Gtk.Widget++instance BinChild Gtk.ScrolledWindow Widget where+  getChild scrolledWindow = do+    viewPort <- getBinChild Gtk.Viewport scrolledWindow+    getBinChild Gtk.Widget viewPort++instance BinChild Gtk.ListBoxRow Widget where+  getChild = getBinChild Gtk.Widget++-- | Declarative version of a /bin/ widget, i.e. a widget with exactly one+-- child.+data Bin widget child event where+  Bin+    :: ( Typeable widget+       , Gtk.IsContainer widget+       , Gtk.IsBin widget+       , Gtk.IsWidget widget+       , Functor child+       )+    => (Gtk.ManagedPtr widget -> widget)+    -> [Attribute widget event]+    -> child event+    -> Bin widget child event++instance Functor (Bin widget child) where+  fmap f (Bin ctor attrs child) =+    Bin ctor (fmap f <$> attrs) (fmap f child)++-- | Construct a /bin/ widget, i.e. a widget with exactly one child.+bin ::+     ( Patchable (Bin widget child)+     , Typeable widget+     , Typeable child+     , Typeable event+     , Functor child+     , Gtk.IsContainer widget+     , Gtk.IsBin widget+     , Gtk.IsWidget widget+     , FromWidget (Bin widget child) event target+     , BinChild widget child+     )+  => (Gtk.ManagedPtr widget -> widget) -- ^ A bin widget constructor from the underlying gi-gtk library.+  -> [Attribute widget event]          -- ^ List of 'Attribute's.+  -> child event                       -- ^ The bin's child widget, whose type is decided by the 'BinChild' instance.+  -> target                            -- ^ The target, whose type is decided by 'FromWidget'.+bin ctor attrs = fromWidget . Bin ctor attrs++--+-- Patchable+--++instance (BinChild parent child, Patchable child) => Patchable (Bin parent child) where+  create (Bin ctor props child) = do+    let attrOps = concatMap extractAttrConstructOps props+    widget' <- Gtk.new ctor attrOps++    sc <- Gtk.widgetGetStyleContext widget'+    mapM_ (addClass sc) props++    Gtk.containerAdd widget' =<< create child+    Gtk.toWidget widget'++  patch (Bin _ oldAttributes oldChild) (Bin ctor newAttributes newChild) =+    Modify $ \widget' -> do++      binWidget <- Gtk.unsafeCastTo ctor widget'+      Gtk.set binWidget (concatMap extractAttrSetOps newAttributes)++      sc <- Gtk.widgetGetStyleContext binWidget+      mapM_ (removeClass sc) oldAttributes+      mapM_ (addClass sc) newAttributes++      childWidget <- getChild binWidget++      case patch oldChild newChild of+        Modify modify -> modify childWidget+        Replace createNew -> do+          Gtk.containerRemove binWidget childWidget+          Gtk.containerAdd binWidget =<< createNew+        Keep -> return ()++--+-- EventSource+--++instance (BinChild parent child, EventSource child) =>+         EventSource (Bin parent child) where+  subscribe (Bin ctor props child) widget' cb = do+    binWidget <- Gtk.unsafeCastTo ctor widget'+    handlers' <-+      mconcat . catMaybes <$> mapM (addSignalHandler cb binWidget) props+    childWidget <- getChild binWidget+    (<> handlers') <$> subscribe child childWidget cb++--+-- FromWidget+--++instance ( BinChild widget child+         , Typeable widget+         , Patchable child+         , EventSource child+         , Functor (Bin widget child)+         ) =>+         FromWidget (Bin widget child) event (Widget event) where+  fromWidget = Widget++instance a ~ () => FromWidget (Bin widget child) event (MarkupOf (Bin widget child) event a) where+  fromWidget = single++instance ( BinChild widget child+         , a ~ ()+         , Typeable widget+         , Patchable child+         , EventSource child+         , Functor (Bin widget child)+         ) =>+         FromWidget (Bin widget child) event (Markup event a) where+  fromWidget = single . Widget+++-- | Get a "Gtk.Bin" child, or fail, and cast it to the given widget type.+getBinChild+  :: (Gtk.IsBin bin, GI.GObject child)+  => (Gtk.ManagedPtr child -> child)+  -> bin+  -> IO child+getBinChild ctor =+  Gtk.binGetChild+    >=> maybe (fail "expected Bin to have a child") return+    >=> Gtk.unsafeCastTo ctor
+ src/GI/Gtk/Declarative/CSS.hs view
@@ -0,0 +1,35 @@+-- | Helpers for modifying CSS classes in 'Gtk.StyleContext'+-- objects.++module GI.Gtk.Declarative.CSS where++import           Data.HashSet (HashSet)+import qualified Data.HashSet as HashSet+import           Data.Text    (Text)+import qualified GI.Gtk       as Gtk++-- | A set of CSS classes.+type ClassSet = HashSet Text++-- | Add the classes to the widget's style context.+addClasses+  :: Gtk.IsWidget w+  => w        -- ^ The widget to add classes to.+  -> ClassSet -- ^ New classes to add.+  -> IO ()+addClasses widget cs = do+  sc <- Gtk.widgetGetStyleContext widget+  mapM_ (Gtk.styleContextAddClass sc) cs++-- | Replace all classes in 'old' with the ones in 'old' in the widget's style+-- context.+replaceClasses+  :: Gtk.IsWidget w+  => w        -- ^ The widget to replace classes in.+  -> ClassSet -- ^ Old classes to replace.+  -> ClassSet -- ^ New classes to replace with.+  -> IO ()+replaceClasses widget old new = do+  sc <- Gtk.widgetGetStyleContext widget+  mapM_ (Gtk.styleContextRemoveClass sc) (HashSet.difference old new)+  mapM_ (Gtk.styleContextAddClass sc)    (HashSet.difference new old)
+ src/GI/Gtk/Declarative/Container.hs view
@@ -0,0 +1,146 @@+{-# OPTIONS_GHC -fno-warn-unticked-promoted-constructors #-}+{-# LANGUAGE DataKinds              #-}+{-# LANGUAGE DeriveFunctor          #-}+{-# LANGUAGE FlexibleContexts       #-}+{-# LANGUAGE FlexibleInstances      #-}+{-# LANGUAGE FunctionalDependencies #-}+{-# LANGUAGE GADTs                  #-}+{-# LANGUAGE LambdaCase             #-}+{-# LANGUAGE MultiParamTypeClasses  #-}+{-# LANGUAGE OverloadedLabels       #-}+{-# LANGUAGE ScopedTypeVariables    #-}+{-# LANGUAGE TypeFamilies           #-}+{-# LANGUAGE TypeOperators          #-}++-- | Implementations for common "Gtk.Container".++module GI.Gtk.Declarative.Container+  ( Container+  , container+  )+where++import           Control.Monad                      (forM_)+import           Data.Maybe+import           Data.Typeable+import qualified GI.Gtk                             as Gtk++import           GI.Gtk.Declarative.Attributes+import           GI.Gtk.Declarative.Attributes.Internal+import           GI.Gtk.Declarative.Container.Patch+import           GI.Gtk.Declarative.EventSource+import           GI.Gtk.Declarative.Markup+import           GI.Gtk.Declarative.Patch++-- | Declarative version of a /container/ widget, i.e. a widget with zero+-- or more child widgets. The type of 'children' is parameterized, and differs+-- across the supported container widgets, as some containers require specific+-- types of child widgets. These type relations are decided by 'IsContainer',+-- and instances can found in "GI.Gtk.Declarative.Container.Patch".+data Container widget children event where+  Container+    :: ( Typeable widget+       , Gtk.IsWidget widget+       , Gtk.IsContainer widget+       , Functor children+       )+    => (Gtk.ManagedPtr widget -> widget)+    -> [Attribute widget event]+    -> children event+    -> Container widget children event++instance Functor (Container widget children) where+  fmap f (Container ctor attrs children) =+    Container ctor (fmap f <$> attrs) (fmap f children)++-- | Construct a /container/ widget, i.e. a widget with zero or more children.+container+  :: ( Patchable (Container widget (Children child))+     , Typeable widget+     , Typeable child+     , Typeable event+     , Functor child+     , Gtk.IsWidget widget+     , Gtk.IsContainer widget+     , FromWidget (Container widget (Children child)) event target+     )+  => (Gtk.ManagedPtr widget -> widget) -- ^ A container widget constructor from the underlying gi-gtk library.+  -> [Attribute widget event]          -- ^ List of 'Attribute's.+  -> MarkupOf child event ()           -- ^ The container's 'child' widgets, in a 'MarkupOf' builder.+  -> target                            -- ^ The target, whose type is decided by 'FromWidget'.+container ctor attrs = fromWidget . Container ctor attrs . toChildren++newtype Children child event = Children { unChildren :: [child event] }+  deriving (Functor)++toChildren :: MarkupOf child event () -> Children child event+toChildren = Children . runMarkup++--+-- Patchable+--++instance (Patchable child, IsContainer container child) =>+         Patchable (Container container (Children child)) where+  create (Container ctor props children) = do+    let attrOps = concatMap extractAttrConstructOps props+    widget' <- Gtk.new ctor attrOps+    sc <- Gtk.widgetGetStyleContext widget'+    mapM_ (addClass sc) props+    forM_ (unChildren children) $ \child -> do+      childWidget <- create child+      appendChild widget' child childWidget+    Gtk.toWidget widget'+  patch (Container _ oldAttributes oldChildren) (Container ctor newAttributes newChildren) =+    Modify $ \widget' -> do+      containerWidget <- Gtk.unsafeCastTo ctor widget'+      Gtk.set containerWidget (concatMap extractAttrSetOps newAttributes)+      sc <- Gtk.widgetGetStyleContext widget'+      mapM_ (removeClass sc) oldAttributes+      mapM_ (addClass sc) newAttributes+      patchInContainer+        containerWidget+        (unChildren oldChildren)+        (unChildren newChildren)++--+-- EventSource+--++instance (Typeable child, EventSource child) =>+         EventSource (Container widget (Children child)) where+  subscribe (Container ctor props children) widget' cb = do+    parentWidget <- Gtk.unsafeCastTo ctor widget'+    handlers' <- mconcat . catMaybes <$> mapM (addSignalHandler cb parentWidget) props+    childWidgets <- Gtk.containerGetChildren parentWidget+    subs <-+      flip foldMap (zip (unChildren children) childWidgets) $ \(c, w) ->+        subscribe c w cb+    return (handlers' <> subs)++--+-- FromWidget+--++instance ( Typeable widget+         , Typeable children+         , Patchable (Container widget children)+         , EventSource (Container widget children)+         , Functor (Container widget children)+         ) =>+         FromWidget (Container widget children) event (Widget event) where+  fromWidget = Widget++instance a ~ () =>+         FromWidget (Container widget children) event (MarkupOf (Container widget children) event a) where+  fromWidget = single++instance ( a ~ ()+         , Typeable widget+         , Typeable children+         , Patchable (Container widget children)+         , EventSource (Container widget children)+         , Functor (Container widget children)+         ) =>+         FromWidget (Container widget children) event (Markup event a) where+  fromWidget = single . Widget
+ src/GI/Gtk/Declarative/Container/Box.hs view
@@ -0,0 +1,52 @@+{-# OPTIONS_GHC -fno-warn-unticked-promoted-constructors #-}+{-# LANGUAGE DataKinds              #-}+{-# LANGUAGE DeriveFunctor          #-}+{-# LANGUAGE FlexibleContexts       #-}+{-# LANGUAGE FlexibleInstances      #-}+{-# LANGUAGE FunctionalDependencies #-}+{-# LANGUAGE GADTs                  #-}+{-# LANGUAGE LambdaCase             #-}+{-# LANGUAGE MultiParamTypeClasses  #-}+{-# LANGUAGE OverloadedLabels       #-}+{-# LANGUAGE RecordWildCards        #-}+{-# LANGUAGE ScopedTypeVariables    #-}+{-# LANGUAGE TypeFamilies           #-}+{-# LANGUAGE TypeOperators          #-}++-- | Implementation of 'Gtk.Box' as a declarative container.+module GI.Gtk.Declarative.Container.Box+  ( BoxChild(..)+  , boxChild+  )+where++import           Data.Word                      (Word32)++import           GI.Gtk.Declarative.EventSource+import           GI.Gtk.Declarative.Patch+import           GI.Gtk.Declarative.Markup++-- | Described a child widget to be added with 'boxAppend' to a 'Box'.+data BoxChild event = BoxChild+  { expand  :: Bool+  , fill    :: Bool+  , padding :: Word32+  , child   :: Widget event+  }+  deriving (Functor)++-- | Construct a box child with the given 'boxAppend' parameters.+boxChild+  :: Bool+  -> Bool+  -> Word32+  -> Widget event+  -> MarkupOf BoxChild event ()+boxChild expand fill padding child = single BoxChild {..}++instance Patchable BoxChild where+  create = create . child+  patch b1 b2 = patch (child b1) (child b2)++instance EventSource BoxChild where+  subscribe BoxChild{..} = subscribe child
+ src/GI/Gtk/Declarative/Container/Patch.hs view
@@ -0,0 +1,120 @@+{-# OPTIONS_GHC -fno-warn-unticked-promoted-constructors #-}++{-# LANGUAGE DataKinds              #-}+{-# LANGUAGE FlexibleContexts       #-}+{-# LANGUAGE FlexibleInstances      #-}+{-# LANGUAGE FunctionalDependencies #-}+{-# LANGUAGE GADTs                  #-}+{-# LANGUAGE LambdaCase             #-}+{-# LANGUAGE MultiParamTypeClasses  #-}+{-# LANGUAGE OverloadedLabels       #-}+{-# LANGUAGE RecordWildCards        #-}+{-# LANGUAGE ScopedTypeVariables    #-}+{-# LANGUAGE TypeFamilies           #-}+{-# LANGUAGE TypeOperators          #-}++-- | This module implements the patch algorithm for containers.+module GI.Gtk.Declarative.Container.Patch (IsContainer(..), patchInContainer) where++import           Control.Monad                    (forM_)+import           Data.Int                         (Int32)+import           Data.List                        (zip4)+import qualified GI.Gtk                           as Gtk++import           GI.Gtk.Declarative.Bin+import           GI.Gtk.Declarative.Container.Box+import           GI.Gtk.Declarative.Markup+import           GI.Gtk.Declarative.Patch+++-- | Describes supported GTK+ containers and their specialized APIs for+-- appending and replacing child widgets.+class IsContainer container child | container -> child where+  -- | Append a child widget to the container.+  appendChild+    :: container    -- ^ Container widget+    -> child event  -- ^ Declarative child widget+    -> Gtk.Widget   -- ^ GTK child widget to append+    -> IO ()+  -- | Replace the child widget at the given index in the container.+  replaceChild+    :: container    -- ^ Container widget+    -> child event  -- ^ Declarative child widget+    -> Int32        -- ^ Index to replace at+    -> Gtk.Widget   -- ^ Old GTK widget to replace+    -> Gtk.Widget   -- ^ New GTK widget to replace with+    -> IO ()++-- | Patch all children in a container. This does not feature any ID checking,+-- as seen in React, so reordering children in a container can produce many+-- updates.+patchInContainer+  :: ( Gtk.IsWidget container+     , Gtk.IsContainer container+     , Patchable child+     , IsContainer container child+     )+  => container+  -> [child e1]+  -> [child e2]+  -> IO ()+patchInContainer container os' ns' = do+  cs <- Gtk.containerGetChildren container+  let maxLength = maximum [length cs, length os', length ns']+      indices   = [0 .. pred (fromIntegral maxLength)]+  forM_ (zip4 indices (padMaybes cs) (padMaybes os') (padMaybes ns')) $ \case++    -- In case we have a corresponding old and new declarative widget, we patch+    -- the GTK widget.+    (i, Just w, Just old, Just new) -> case patch old new of+      Modify  modify       -> modify w+      Replace createWidget -> replaceChild container new i w =<< createWidget+      Keep                 -> return ()++    -- When there is a new declarative widget, but there already exists a GTK+    -- widget in the corresponding place, we need to replace the GTK widget with+    -- one created from the declarative widget.+    (i, Just w, Nothing, Just new) ->+      replaceChild container new i w =<< create new++    -- When there is a new declarative widget, or one that lacks a corresponding+    -- GTK widget, create and add it.+    (_i, Nothing, _      , Just n ) -> create n >>= appendChild container n++    -- When an declarative widget has been removed, remove the GTK widget from+    -- the container.+    (_i, Just w , Just _ , Nothing) -> Gtk.containerRemove container w++    -- When there are more old declarative widgets than GTK widgets, we can+    -- safely ignore the old declarative widgets.+    (_i, Nothing, Just _ , Nothing) -> return ()++    -- But, when there are stray GTK widgets without corresponding+    -- declarative widgets, something has gone wrong, and we clean that up by+    -- removing the GTK widgets.+    (_i, Just w , Nothing, Nothing) -> Gtk.containerRemove container w++    -- No more GTK widgets or declarative widgets, we are done.+    (_i, Nothing, Nothing, Nothing) -> return ()++  Gtk.widgetQueueResize container++instance IsContainer Gtk.ListBox (Bin Gtk.ListBoxRow Widget) where+  appendChild box _ widget' = Gtk.listBoxInsert box widget' (-1)+  replaceChild box _ i old new = do+    Gtk.containerRemove box old+    Gtk.listBoxInsert box new i+    Gtk.widgetShowAll box++instance IsContainer Gtk.Box BoxChild where+  appendChild box BoxChild {..} widget' =+    Gtk.boxPackStart box widget' expand fill padding++  replaceChild box boxChild' i old new = do+    Gtk.containerRemove box old+    appendChild box boxChild' new+    Gtk.boxReorderChild box new i+    Gtk.widgetShowAll box++padMaybes :: [a] -> [Maybe a]+padMaybes xs = map Just xs ++ repeat Nothing
+ src/GI/Gtk/Declarative/EventSource.hs view
@@ -0,0 +1,41 @@+{-# LANGUAGE FunctionalDependencies     #-}+{-# LANGUAGE GeneralizedNewtypeDeriving #-}+{-# LANGUAGE MultiParamTypeClasses      #-}++-- | Event handling for declarative widgets.+module GI.Gtk.Declarative.EventSource+  ( EventSource (..)+  , Subscription+  , fromCancellation+  , cancel+  )+where++import qualified GI.Gtk               as Gtk++-- | Cancel a 'Subscription', meaning that the callback will not be invoked on+-- any subsequent signal emissions.+cancel :: Subscription -> IO ()+cancel = sequence_ . cancellations++-- | An 'EventSource' can be subscribed to, with a callback, returning a+-- 'Subscription'.+class EventSource widget where+  subscribe+    :: widget event     -- ^ Declarative widget with event handlers.+    -> Gtk.Widget       -- ^ Actual 'Gtk.Widget' that has been created or patched.+    -> (event -> IO ()) -- ^ Event callback, invoked on each emitted event until+                        -- the 'Subscription' is cancelled, or widget is otherwise+                        -- destroyed.+    -> IO Subscription  -- ^ A 'Subscription' is returned, which can be cancelled.++-- | A 'Subscription' contains zero or more cancellation actions for connected+-- handlers (to a tree of widgets.) When subscribing to a container widget, all+-- child widgets are also subscribed to, and the 'Subscription's are combined+-- using the 'Semigroup' instance.+newtype Subscription = Subscription { cancellations :: [IO ()] }+  deriving (Semigroup, Monoid)++-- | Create a subscription from a cancellation IO action.+fromCancellation :: IO () -> Subscription+fromCancellation = Subscription . pure
+ src/GI/Gtk/Declarative/Markup.hs view
@@ -0,0 +1,104 @@+{-# LANGUAGE FlexibleInstances          #-}+{-# LANGUAGE FunctionalDependencies     #-}+{-# LANGUAGE GADTs                      #-}+{-# LANGUAGE GeneralizedNewtypeDeriving #-}+{-# LANGUAGE MultiParamTypeClasses      #-}+{-# LANGUAGE ScopedTypeVariables        #-}+{-# LANGUAGE TypeApplications           #-}+{-# LANGUAGE TypeOperators              #-}++-- | 'MarkupOf' is the common builder type for the (declarative) GTK+ markup+-- language, supporting do syntax. 'MarkupOf' wraps many widgets, usually of+-- type 'Widget', but they can be of other types.+--+-- A 'Widget' value can wrap any 'Patchable' widget, hiding the underlying+-- widget type, such that you can embed heterogeneous collections of widgets in+-- containers.+module GI.Gtk.Declarative.Markup+  ( Widget(..)+  -- * Markup+  , MarkupOf+  , Markup+  , single+  , multiple+  , runMarkup+  -- * Widget to Markup conversion+  , FromWidget(..)+  )+where++import           Control.Monad.Writer+import           Data.Typeable++import           GI.Gtk.Declarative.EventSource+import           GI.Gtk.Declarative.Patch++-- | A 'Widget' value wraps a 'Patchable' and 'EventSource' widget, providing+-- a constrained equivalent of a 'Dynamic' value. It is used to support+-- heterogeneous containers of widgets, and to support equality+-- checks on different types of widgets when calculating patches.+data Widget event where+  Widget+    :: ( Typeable widget+       , Patchable widget+       , Functor widget+       , EventSource widget+       )+    => widget event+    -> Widget event++instance Functor Widget where+  fmap f (Widget w) = Widget (fmap f w)++-- | 'Widget' is itself patchable, by delegating to the underlying+-- widget instances.+instance Patchable Widget where+  create (Widget w) = create w+  patch (Widget (w1 :: t1 e1)) (Widget (w2 :: t2 e2)) =+    case eqT @t1 @t2 of+      Just Refl -> patch w1 w2+      _         -> Replace (create w2)++instance EventSource Widget where+  subscribe (Widget w) = subscribe w++-- * Markup++-- | The declarative markup builder, primarily for using its 'Monad' instance+-- and do notation to construct adjacent widgets in containers.+--+-- It is parameterized with 'widget' and 'event', such that containers can+-- restrict the type of their children to other types than 'Widget'.+--+-- Note that the return type, 'a', is not used in this library. It's a more a+-- technical necessity to have the 'Monad' instance. You can still use it if+-- you need to return a value from a markup function, though.+newtype MarkupOf widget event a =+  MarkupOf (Writer [widget event] a)+  deriving (Functor, Applicative, Monad)++-- | Run a 'MarkupOf' builder and get its widgets.+runMarkup :: MarkupOf widget event () -> [widget event]+runMarkup (MarkupOf w) = execWriter w++-- | Handy type alias for the common case of markup containing 'Widget's.+type Markup event a = MarkupOf Widget event a++-- | Construct markup from a single widget.+single :: widget event -> MarkupOf widget event ()+single w = MarkupOf (tell [w])++-- | Construct markup from multiple widgets.+multiple :: [widget event] -> MarkupOf widget event ()+multiple = MarkupOf . tell++-- | Convert a widget to a target type. This is deliberately unconstrained in+-- it's types, and is used by smart constructors to implement return type+-- polymorphism, so that a smart contructor can return either a 'Widget', or+-- some specifically typed 'MarkupOf', depending on the context in which it's+-- used.+class FromWidget widget event target | target -> event where+  fromWidget :: (Typeable widget, Typeable event) => widget event -> target++instance FromWidget Widget event (Widget event) where+  fromWidget = id
+ src/GI/Gtk/Declarative/Patch.hs view
@@ -0,0 +1,34 @@+{-# LANGUAGE MultiParamTypeClasses #-}+{-# LANGUAGE RankNTypes            #-}++module GI.Gtk.Declarative.Patch+  ( Patch(..)+  , Patchable(..)+  ) where++import qualified GI.Gtk as Gtk++-- | A possible action to take on an existing 'Gtk.Widget', decided by the+-- 'patch' method when comparing declarative widgets.+data Patch+  = Modify (Gtk.Widget -> IO ())+  -- ^ An 'IO' action to apply to a 'Gtk.Widget' to make it reflect an updated+  -- declarative widget. The action to apply is calculated from the difference+  -- between the old and the new declarative widget.+  | Replace (IO Gtk.Widget)+  -- ^ Replace the current 'Gtk.Widget' by the widget returned by the IO+  -- action.+  | Keep+  -- ^ Do nothing, i.e. keep the 'Gtk.Widget' as it is.++-- | A patchable widget is one that can create an underlying GTK widget, or+-- calculate a 'Patch' to be applied to an existing GTK widget that was+-- previously created.+class Patchable widget where+  -- | Given a declarative widget that is 'Patchable', return an IO action that+  -- can create a new corresponding 'Gtk.Widget'. The created widget should be+  -- use in corresponding patch modifications, until it is replaced.+  create :: widget e -> IO Gtk.Widget+  -- | Given two declarative widgets of the same widget type (but not+  -- necessarily of the same event types,) calculate a 'Patch'.+  patch :: widget e1 -> widget e2 -> Patch
+ src/GI/Gtk/Declarative/SingleWidget.hs view
@@ -0,0 +1,94 @@+{-# LANGUAGE DataKinds             #-}+{-# LANGUAGE FlexibleContexts      #-}+{-# LANGUAGE FlexibleInstances     #-}+{-# LANGUAGE GADTs                 #-}+{-# LANGUAGE LambdaCase            #-}+{-# LANGUAGE MultiParamTypeClasses #-}+{-# LANGUAGE RankNTypes            #-}+{-# LANGUAGE ScopedTypeVariables   #-}+{-# LANGUAGE TypeApplications      #-}+{-# LANGUAGE TypeOperators         #-}++-- | A declarative representation of 'Gtk.Widget' in GTK without children.+module GI.Gtk.Declarative.SingleWidget+  ( SingleWidget+  , widget+  )+where++import           Data.Maybe+import           Data.Typeable+import qualified GI.Gtk                         as Gtk++import           GI.Gtk.Declarative.Attributes+import           GI.Gtk.Declarative.Attributes.Internal+import           GI.Gtk.Declarative.EventSource+import           GI.Gtk.Declarative.Markup+import           GI.Gtk.Declarative.Patch++-- | Declarative version of a /leaf/ widget, i.e. a widget without any children.+data SingleWidget widget event where+  SingleWidget+    :: (Typeable widget, Gtk.IsWidget widget, Functor (Attribute widget))+    => (Gtk.ManagedPtr widget -> widget)+    -> [Attribute widget event]+    -> SingleWidget widget event++instance Functor (SingleWidget widget) where+  fmap f (SingleWidget ctor attrs) = SingleWidget ctor (fmap f <$> attrs)++instance Patchable (SingleWidget widget) where+  create = \case+    (SingleWidget ctor props) -> do+        let attrOps = concatMap extractAttrConstructOps props+        widget' <- Gtk.new ctor attrOps++        sc <- Gtk.widgetGetStyleContext widget'+        mapM_ (addClass sc) props++        Gtk.widgetShowAll widget'+        Gtk.toWidget widget'+  patch (SingleWidget (_    :: Gtk.ManagedPtr w1 -> w1) oldAttributes)+        (SingleWidget (ctor :: Gtk.ManagedPtr w2 -> w2) newAttributes) =+    case eqT @w1 @w2 of+      Just Refl ->+        Modify $ \widget' -> do+          w <- Gtk.unsafeCastTo ctor widget'+          Gtk.set w (concatMap extractAttrSetOps newAttributes)++          sc <- Gtk.widgetGetStyleContext widget'+          mapM_ (removeClass sc) oldAttributes+          mapM_ (addClass sc) newAttributes++          Gtk.widgetShowAll w++      Nothing -> Replace (create (SingleWidget ctor newAttributes))++instance EventSource (SingleWidget widget) where+  subscribe (SingleWidget ctor props) widget' cb = do+    w <- Gtk.unsafeCastTo ctor widget'+    mconcat . catMaybes <$> mapM (addSignalHandler cb w) props++instance (Typeable widget, Functor (SingleWidget widget))+  => FromWidget (SingleWidget widget) event (Widget event) where+  fromWidget = Widget++instance FromWidget (SingleWidget widget) event (MarkupOf (SingleWidget widget) event ()) where+  fromWidget = single++instance (Typeable widget, Functor (SingleWidget widget))+  => FromWidget (SingleWidget widget) event (Markup event ()) where+  fromWidget = single . Widget++-- | Construct a /leaf/ widget, i.e. one without any children.+widget ::+     ( Typeable widget+     , Typeable event+     , Functor (Attribute widget)+     , Gtk.IsWidget widget+     , FromWidget (SingleWidget widget) event target+     )+  => (Gtk.ManagedPtr widget -> widget) -- ^ A widget constructor from the underlying gi-gtk library.+  -> [Attribute widget event]          -- ^ List of 'Attribute's.+  -> target                            -- ^ The target, whose type is decided by 'FromWidget'.+widget ctor = fromWidget . SingleWidget ctor