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co-log-core (empty) → 0.0.0

raw patch · 7 files changed

+827/−0 lines, 7 filesdep +base

Dependencies added: base

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+ CHANGELOG.md view
@@ -0,0 +1,13 @@+Change log+==========++co-log uses [PVP Versioning][1].+The change log is available [on GitHub][2].++0.0.0+=====+* Initially created.++[1]: https://pvp.haskell.org+[2]: https://github.com/kowainik/co-log/releases+
+ 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.
+ co-log-core.cabal view
@@ -0,0 +1,33 @@+name:                co-log-core+version:             0.0.0+description:         Logging library+synopsis:            Logging library+homepage:            https://github.com/kowainik/co-log+bug-reports:         https://github.com/kowainik/co-log/issues+license:             MPL-2.0+license-file:        LICENSE+author:              Kowainik+maintainer:          xrom.xkov@gmail.com+copyright:           2018 Kowainik+category:            Logging+build-type:          Simple+extra-doc-files:     CHANGELOG.md+cabal-version:       2.0+tested-with:         GHC == 8.4.3++source-repository head+  type:                git+  location:            https://github.com/kowainik/co-log.git++library+  hs-source-dirs:      src+  exposed-modules:     Colog.Core+                           Colog.Core.Action+                           Colog.Core.Class+                           Colog.Core.Severity++  ghc-options:         -Wall -fhide-source-paths+  build-depends:       base >= 4.11 && < 5++  default-language:    Haskell2010+  default-extensions:  InstanceSigs
+ src/Colog/Core.hs view
@@ -0,0 +1,9 @@+module Colog.Core+       ( module Colog.Core.Action+       , module Colog.Core.Class+       , module Colog.Core.Severity+       ) where++import Colog.Core.Action+import Colog.Core.Class+import Colog.Core.Severity
+ src/Colog/Core/Action.hs view
@@ -0,0 +1,314 @@+{-# LANGUAGE ViewPatterns #-}++{- | Implements core data types and combinators for logging actions.+-}++module Colog.Core.Action+       ( -- * Core type and instances+         LogAction (..)++         -- * 'Semigroup' combinators+       , foldActions++         -- * Contravariant combinators+       , cfilter+       , cmap+       , (>$<)+       , (>$)+       , cbind++         -- * Divisible combinators+       , divide+       , conquer+       , (>*<)+       , (>*)+       , (*<)++         -- * Decidable combinators+       , lose+       , choose+       , (>|<)++         -- * Comonadic combinators+       , extract+       , extend+       , (=>>)+       , (<<=)+       ) where++import Control.Monad (when, (>=>))+import Data.Foldable (for_)+import Data.List.NonEmpty (NonEmpty (..))+import Data.Monoid (Monoid (..))+import Data.Semigroup (Semigroup (..), stimesMonoid)+import Data.Void (Void, absurd)++----------------------------------------------------------------------------+-- Core data type with instances+----------------------------------------------------------------------------++{- | Polymorphic and very general logging action type.++* @__msg__@ type variables is an input for logger. It can be 'Text' or custom+logging messsage with different fields that you want to format in future.++* @__m__@ type variable is for monadic action inside which logging is happening. It+can be either 'IO' or some custom pure monad.++Key design point here is that 'LogAction' is:++* 'Semigroup'+* Contravariant+* Comonad+-}+newtype LogAction m msg = LogAction+    { unLogAction :: msg -> m ()+    }++{- | This instance allows you to join multiple logging actions into single one.++For example, if you have two actions like these:++@+logToStdout :: 'LogAction' IO String  -- outputs String to terminal+logToFile   :: 'LogAction' IO String  -- appends String to some file+@++You can create new 'LogAction' that perform both actions one after another using 'Semigroup':++@+logToBoth :: 'LogAction' IO String  -- outputs String to both terminal and some file+logToBoth = logToStdout <> logToFile+@+-}+instance Applicative m => Semigroup (LogAction m a) where+    (<>) :: LogAction m a -> LogAction m a -> LogAction m a+    LogAction action1 <> LogAction action2 = LogAction $ \a -> action1 a *> action2 a+    {-# INLINE (<>) #-}++    sconcat :: NonEmpty (LogAction m a) -> LogAction m a+    sconcat = foldActions+    {-# INLINE sconcat #-}++    stimes :: Integral b => b -> LogAction m a -> LogAction m a+    stimes = stimesMonoid+    {-# INLINE stimes #-}++instance Applicative m => Monoid (LogAction m a) where+    mappend :: LogAction m a -> LogAction m a -> LogAction m a+    mappend = (<>)+    {-# INLINE mappend #-}++    mempty :: LogAction m a+    mempty = LogAction $ \_ -> pure ()+    {-# INLINE mempty #-}++    mconcat :: [LogAction m a] -> LogAction m a+    mconcat = foldActions+    {-# INLINE mconcat #-}++----------------------------------------------------------------------------+-- Combinators+----------------------------------------------------------------------------++{- | Joins some 'Foldable' of 'LogAction's into single 'LogAction' using+'Semigroup' instance for 'LogAction'. This is basically specialized version of+'Data.Foldable.fold' function.+-}+foldActions :: (Foldable t, Applicative m) => t (LogAction m a) -> LogAction m a+foldActions actions = LogAction $ \a -> for_ actions $ \(LogAction action) -> action a+{-# INLINE foldActions #-}+{-# SPECIALIZE foldActions :: Applicative m => [LogAction m a]          -> LogAction m a #-}+{-# SPECIALIZE foldActions :: Applicative m => NonEmpty (LogAction m a) -> LogAction m a #-}++{- | Takes predicate and performs given logging action only if predicate returns+'True' on input logging message.+-}+cfilter :: Applicative m => (msg -> Bool) -> LogAction m msg -> LogAction m msg+cfilter predicate (LogAction action) = LogAction $ \a -> when (predicate a) (action a)+{-# INLINE cfilter #-}++{- | This combinator is @contramap@ from contravariant functor. It is useful+when you have something like++@+__data__ LogRecord = LR+    { lrName    :: LoggerName+    , lrMessage :: Text+    }+@++and you need to provide 'LogAction' which consumes @LogRecord@++@+logRecordAction :: 'LogAction' m LogRecord+@++when you only have action that consumes 'Text'++@+logTextAction :: 'LogAction' m Text+@++With 'cmap' you can do the following:++@+logRecordAction :: 'LogAction' m LogRecord+logRecordAction = 'cmap' lrMesssage logTextAction+@++This action will print only @lrMessage@ from @LogRecord@. But if you have+formatting function like this:++@+formatLogRecord :: LogRecord -> Text+@++you can apply it instead of @lrMessage@ to log formatted @LogRecord@ as 'Text'.+-}+cmap :: (a -> b) -> LogAction m b -> LogAction m a+cmap f (LogAction action) = LogAction (action . f)+{-# INLINE cmap #-}++-- | Operator version of 'cmap'.+infixr 3 >$<+(>$<) :: (a -> b) -> LogAction m b -> LogAction m a+(>$<) = cmap+{-# INLINE (>$<) #-}++{- | This combinator is @>$@ from contravariant functor. Replaces all locations+in the output with the same value. The default definition is+@contramap . const@, so this is a more efficient version.+-}+infixl 4 >$+(>$) :: b -> LogAction m b -> LogAction m a+(>$) b (LogAction action) = LogAction (\_ -> action b)++{- | 'cbind' combinator is similar to 'cmap' but allows to call monadic+functions (functions that require extra context) to extend consumed value.+Consider the following example.++You have this logging record:++@+__data__ LogRecord = LR+    { lrTime    :: UTCTime+    , lrMessage :: Text+    }+@++and you also have logging consumer inside 'IO' for such record:++@+logRecordAction :: 'LogAction' IO LogRecord+@++But you need to return consumer only for 'Text' messages:++@+logTextAction :: 'LogAction' IO Text+@++If you have function that can extend 'Text' to @LogRecord@ like the function+below:++@+withTime :: 'Text' -> 'IO' LogRecord+withTime msg = __do__+    time <- getCurrentTime+    pure (LR time msg)+@++you can achieve desired behavior with 'cbind' in the following way:++@+logTextAction :: 'LogAction' IO Text+logTextAction = 'cbind' withTime myAction+@+-}+cbind :: Monad m => (a -> m b) -> LogAction m b -> LogAction m a+cbind f (LogAction action) = LogAction (f >=> action)+{-# INLINE cbind #-}++-- | @divide@ combinator from @Divisible@ type class.+divide :: (Applicative m) => (a -> (b, c)) -> LogAction m b -> LogAction m c -> LogAction m a+divide f (LogAction actionB) (LogAction actionC) = LogAction $ \(f -> (b, c)) ->+    actionB b *> actionC c++-- | @conquer@ combinator from @Divisible@ type class.+conquer :: Applicative m => LogAction m a+conquer = LogAction $ const (pure ())+++-- | Operator version of @'divide' 'id'@.+infixr 4 >*<+(>*<) :: (Applicative m) => LogAction m a -> LogAction m b -> LogAction m (a, b)+(LogAction actionA) >*< (LogAction actionB) = LogAction $ \(a, b) ->+    actionA a *> actionB b+{-# INLINE (>*<) #-}++infixr 4 >*+(>*) :: Applicative m => LogAction m a -> LogAction m () -> LogAction m a+(LogAction actionA) >* (LogAction actionB) = LogAction $ \a ->+    actionA a *> actionB ()+{-# INLINE (>*) #-}++infixr 4 *<+(*<) :: Applicative m => LogAction m () -> LogAction m a -> LogAction m a+(LogAction actionA) *< (LogAction actionB) = LogAction $ \a ->+    actionA () *> actionB a+{-# INLINE (*<) #-}++-- | @lose@ combinator from @Decidable@ type class.+lose :: (a -> Void) -> LogAction m a+lose f = LogAction (absurd . f)++-- | @choose@ combinator from @Decidable@ type class.+choose :: (a -> Either b c) -> LogAction m b -> LogAction m c -> LogAction m a+choose f (LogAction actionB) (LogAction actionC) = LogAction (either actionB actionC . f)++-- | Operator version of @'choose' 'id'@.+infixr 3 >|<+(>|<) :: LogAction m a -> LogAction m b -> LogAction m (Either a b)+(LogAction actionA) >|< (LogAction actionB) = LogAction (either actionA actionB)+{-# INLINE (>|<) #-}++{- | If @msg@ is 'Monoid' then 'extract' performs given log action by passing+'mempty' to it.+-}+extract :: Monoid msg => LogAction m msg -> m ()+extract action = unLogAction action mempty++-- TODO: write better motivation for comonads+{- | This is a /comonadic extend/. It allows you to chain different transformations on messages.++>>> logToStdout = LogAction putStrLn+>>> f (LogAction l) = l ".f1" *> l ".f2"+>>> g (LogAction l) = l ".g"+>>> unLogAction logToStdout "foo"+foo+>>> unLogAction (extend f logToStdout) "foo"+foo.f1+foo.f2+>>> unLogAction (extend g $ extend f logToStdout) "foo"+foo.g.f1+foo.g.f2+>>> unLogAction (logToStdout =>> f =>> g) "foo"+foo.g.f1+foo.g.f2++-}+extend :: Semigroup msg => (LogAction m msg -> m ()) -> LogAction m msg -> LogAction m msg+extend f (LogAction action) = LogAction $ \m -> f $ LogAction $ \m' -> action (m <> m')++-- | 'extend' with the arguments swapped. Dual to '>>=' for a 'Monad'.+infixl 1 =>>+(=>>) :: Semigroup msg => LogAction m msg -> (LogAction m msg -> m ()) -> LogAction m msg+(=>>) = flip extend+{-# INLINE (=>>) #-}++-- | 'extend' in operator form.+infixr 1 <<=+(<<=) :: Semigroup msg => (LogAction m msg -> m ()) -> LogAction m msg -> LogAction m msg+(<<=) = extend+{-# INLINE (<<=) #-}
+ src/Colog/Core/Class.hs view
@@ -0,0 +1,28 @@+{-# LANGUAGE FlexibleInstances     #-}+{-# LANGUAGE MultiParamTypeClasses #-}++{- | Provides type class for objects that has access to 'LogAction'.+-}++module Colog.Core.Class+       ( HasLog (..)+       , overLogAction+       ) where++import Colog.Core.Action (LogAction)++{- | This types class contains simple pair of getter-setter.++TODO: laws+-}+class HasLog env msg m where+    getLogAction :: env -> LogAction m msg+    setLogAction :: LogAction m msg -> env -> env++instance HasLog (LogAction m msg) msg m where+    getLogAction = id+    setLogAction = const++overLogAction :: HasLog env msg m => (LogAction m msg -> LogAction m msg) -> env -> env+overLogAction over env = setLogAction (over $ getLogAction env) env+{-# INLINE overLogAction #-}
+ src/Colog/Core/Severity.hs view
@@ -0,0 +1,57 @@+{-# LANGUAGE PatternSynonyms #-}++{- | This module introduces 'Severity' data type for expressing how severe the+message is. Also, it contains useful functions for work with 'Severity'.++-}++module Colog.Core.Severity+       ( Severity (..)+         -- Patterns+       , pattern D+       , pattern I+       , pattern W+       , pattern E+       , filterBySeverity+       ) where++import Data.Ix (Ix)++import Colog.Core.Action (LogAction (..), cfilter)++-- | Severity for the log messages.+data Severity+    {- | Information useful for debug purposes.++    E.g. output of the function that is important for the internal development,+    not for users. Like, the result of SQL query.+    -}+    = Debug+    {- | Normal operational information.++    E.g. describing general steps: starting application, finished downloading.+    -}+    | Info+    {- | General warnings, non-critical failures.++    E.g. couldn't download icon from some service to display.+    -}+    | Warning+    {- | General errors/severe errors.++    E.g. exceptional situations: couldn't syncronize accounts.+    -}+    | Error+    deriving (Show, Read, Eq, Ord, Enum, Bounded, Ix)++pattern D, I, W, E :: Severity+pattern D <- Debug   where D = Debug+pattern I <- Info    where I = Info+pattern W <- Warning where W = Warning+pattern E <- Error   where E = Error+{-# COMPLETE D, I, W, E #-}+++-- | Filters messages by given 'Severity'.+filterBySeverity :: Applicative m => Severity -> (a -> Severity) -> LogAction m a -> LogAction m a+filterBySeverity s fs = cfilter (\a -> fs a >= s)