Modulemonad-logger-0.3.42Haskell2010

Control.Monad.Logger

This module provides the facilities needed for a decoupled logging system.

The MonadLogger class is implemented by monads that give access to a logging facility. If you're defining a custom monad, then you may define an instance of MonadLogger that routes the log messages to the appropriate place (e.g., that's what yesod-core's HandlerT does). Otherwise, you may use the LoggingT monad included in this module (see runStderrLoggingT). To simply discard log message, use NoLoggingT.

As a user of the logging facility, we provide you some convenient Template Haskell splices that use the MonadLogger class. They will record their source file and position, which is very helpful when debugging. See logDebug for more information.

8 types
3 classes
47 values

Packagemonad-logger-0.3.42
Exports58
LanguageHaskell2010
LicenceMIT
SourceLogger.hs

MonadLogger

5 declarations

classclass Monad m => MonadLogger (m :: Type -> Type) where

A Monad which has the ability to log messages in some manner.

Methods

monadLoggerLog :: ToLogStr msg => Loc -> LogSource -> LogLevel -> msg -> m ()

Instances17MonadLogger, …

MonadIO m => MonadLogger (LoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
Monad m => MonadLogger (NoLoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
Monad m => MonadLogger (WriterLoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadLogger m => MonadLogger (ResourceT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadLogger m => MonadLogger (MaybeT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadLogger m => MonadLogger (ExceptT e m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadLogger m => MonadLogger (IdentityT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadLogger m => MonadLogger (ReaderT r m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadLogger m => MonadLogger (StateT s m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadLogger m => MonadLogger (StateT s m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
(MonadLogger m, Monoid w) => MonadLogger (WriterT w m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
(MonadLogger m, Monoid w) => MonadLogger (WriterT w m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadLogger m => MonadLogger (ConduitM i o m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadLogger m => MonadLogger (ContT r m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
(MonadLogger m, Monoid w) => MonadLogger (RWST r w s m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
(MonadLogger m, Monoid w) => MonadLogger (RWST r w s m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadLogger m => MonadLogger (Pipe l i o u m)Defined in monad-logger-0.3.42 · Control.Monad.Logger

classclass (MonadLogger m, MonadIO m) => MonadLoggerIO (m :: Type -> Type) where

An extension of MonadLogger for the common case where the logging action is a simple IO action. The advantage of using this typeclass is that the logging function itself can be extracted as a first-class value, which can make it easier to manipulate monad transformer stacks, as an example.

Methods

askLoggerIO :: m (Loc -> LogSource -> LogLevel -> LogStr -> IO ())
Request the logging function itself.

Instances16MonadLoggerIO, …

MonadIO m => MonadLoggerIO (LoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadIO m => MonadLoggerIO (NoLoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadLoggerIO m => MonadLoggerIO (ResourceT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadLoggerIO m => MonadLoggerIO (MaybeT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadLoggerIO m => MonadLoggerIO (ExceptT e m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadLoggerIO m => MonadLoggerIO (IdentityT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadLoggerIO m => MonadLoggerIO (ReaderT r m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadLoggerIO m => MonadLoggerIO (StateT s m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadLoggerIO m => MonadLoggerIO (StateT s m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
(MonadLoggerIO m, Monoid w) => MonadLoggerIO (WriterT w m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
(MonadLoggerIO m, Monoid w) => MonadLoggerIO (WriterT w m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadLoggerIO m => MonadLoggerIO (ConduitM i o m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadLoggerIO m => MonadLoggerIO (ContT r m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
(MonadLoggerIO m, Monoid w) => MonadLoggerIO (RWST r w s m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
(MonadLoggerIO m, Monoid w) => MonadLoggerIO (RWST r w s m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadLoggerIO m => MonadLoggerIO (Pipe l i o u m)Defined in monad-logger-0.3.42 · Control.Monad.Logger

datadata LogLevel

Instances5Eq, Ord, Read, Show, Lift

Eq LogLevelDefined in monad-logger-0.3.42 · Control.Monad.Logger
Ord LogLevelDefined in monad-logger-0.3.42 · Control.Monad.Logger
Read LogLevelDefined in monad-logger-0.3.42 · Control.Monad.Logger
Show LogLevelDefined in monad-logger-0.3.42 · Control.Monad.Logger
Lift LogLevelDefined in monad-logger-0.3.42 · Control.Monad.Logger

typetype LogLine = (Loc, LogSource, LogLevel, LogStr)

typetype LogSource = Text

Re-export from fast-logger

3 declarations

datadata LogStr

Log message builder. Use (<>) to append two LogStr in O(1).

Instances6Eq, Show, IsString, Semigroup, Monoid, ToLogStr

Eq LogStrDefined in fast-logger-3.2.6 · System.Log.FastLogger.LogStr
Show LogStrDefined in fast-logger-3.2.6 · System.Log.FastLogger.LogStr
IsString LogStrDefined in fast-logger-3.2.6 · System.Log.FastLogger.LogStr
Semigroup LogStrDefined in fast-logger-3.2.6 · System.Log.FastLogger.LogStr
Monoid LogStrDefined in fast-logger-3.2.6 · System.Log.FastLogger.LogStr
ToLogStr LogStrDefined in fast-logger-3.2.6 · System.Log.FastLogger.LogStr

classclass ToLogStr msg where

Types that can be converted to a LogStr. Instances for types from the text library use a UTF-8 encoding. Instances for numerical types use a decimal encoding.

Methods

toLogStr :: msg -> LogStr

Instances21ToLogStr, …

ToLogStr BuilderDefined in fast-logger-3.2.6 · System.Log.FastLogger.LogStr
ToLogStr ByteStringDefined in fast-logger-3.2.6 · System.Log.FastLogger.LogStr
ToLogStr ByteStringDefined in fast-logger-3.2.6 · System.Log.FastLogger.LogStr
ToLogStr ShortByteStringDefined in fast-logger-3.2.6 · System.Log.FastLogger.LogStr
ToLogStr LogStrDefined in fast-logger-3.2.6 · System.Log.FastLogger.LogStr
ToLogStr IntegerDefined in fast-logger-3.2.6 · System.Log.FastLogger.LogStr
ToLogStr StringDefined in fast-logger-3.2.6 · System.Log.FastLogger.LogStr
ToLogStr Int16Defined in fast-logger-3.2.6 · System.Log.FastLogger.LogStr
ToLogStr Int32Defined in fast-logger-3.2.6 · System.Log.FastLogger.LogStr
ToLogStr Int64Defined in fast-logger-3.2.6 · System.Log.FastLogger.LogStr
ToLogStr Int8Defined in fast-logger-3.2.6 · System.Log.FastLogger.LogStr
ToLogStr Word16Defined in fast-logger-3.2.6 · System.Log.FastLogger.LogStr
ToLogStr Word32Defined in fast-logger-3.2.6 · System.Log.FastLogger.LogStr
ToLogStr Word64Defined in fast-logger-3.2.6 · System.Log.FastLogger.LogStr
ToLogStr Word8Defined in fast-logger-3.2.6 · System.Log.FastLogger.LogStr
ToLogStr DoubleDefined in fast-logger-3.2.6 · System.Log.FastLogger.LogStr
ToLogStr FloatDefined in fast-logger-3.2.6 · System.Log.FastLogger.LogStr
ToLogStr IntDefined in fast-logger-3.2.6 · System.Log.FastLogger.LogStr
ToLogStr WordDefined in fast-logger-3.2.6 · System.Log.FastLogger.LogStr
ToLogStr TextDefined in fast-logger-3.2.6 · System.Log.FastLogger.LogStr
ToLogStr TextDefined in fast-logger-3.2.6 · System.Log.FastLogger.LogStr

valuefromLogStr :: LogStr -> ByteString

Converting LogStr to ByteString.

Helper transformers

14 declarations

newtypenewtype LoggingT (m :: Type -> Type) a

Monad transformer that adds a new logging function.

Constructors

LoggingT
- runLoggingT :: (Loc -> LogSource -> LogLevel -> LogStr -> IO ()) -> m a

Instances29MonadTrans, MonadTransControl, MonadRWS, MonadAccum, MonadError, MonadReader, …

MonadTrans LoggingTDefined in monad-logger-0.3.42 · Control.Monad.Logger
MonadTransControl LoggingTDefined in monad-logger-0.3.42 · Control.Monad.Logger
MonadRWS r w s m => MonadRWS r w s (LoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadAccum w m => MonadAccum w (LoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadError e m => MonadError e (LoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadReader r m => MonadReader r (LoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadState s m => MonadState s (LoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadWriter w m => MonadWriter w (LoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadBase b m => MonadBase b (LoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadBaseControl b m => MonadBaseControl b (LoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
Monad m => Monad (LoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
Functor m => Functor (LoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadFail m => MonadFail (LoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
Applicative m => Applicative (LoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
Alternative m => Alternative (LoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadIO m => MonadIO (LoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadCont m => MonadCont (LoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadCatch m => MonadCatch (LoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadMask m => MonadMask (LoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadThrow m => MonadThrow (LoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadUnliftIO m => MonadUnliftIO (LoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadResource m => MonadResource (LoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadActive m => MonadActive (LoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadIO m => MonadLogger (LoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadIO m => MonadLoggerIO (LoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
(Applicative m, Semigroup a) => Semigroup (LoggingT m a)Defined in monad-logger-0.3.42 · Control.Monad.Logger
(Applicative m, Monoid a) => Monoid (LoggingT m a)Defined in monad-logger-0.3.42 · Control.Monad.Logger
type StM (LoggingT m) a = StM m aDefined in monad-logger-0.3.42 · Control.Monad.Logger
type StT LoggingT a = aDefined in monad-logger-0.3.42 · Control.Monad.Logger

valuerunStderrLoggingT :: MonadIO m => LoggingT m a -> m a

Run a block using a MonadLogger instance which prints to stderr.

valuerunStdoutLoggingT :: MonadIO m => LoggingT m a -> m a

Run a block using a MonadLogger instance which prints to stdout.

valuerunChanLoggingT :: MonadIO m => Chan LogLine -> LoggingT m a -> m a

Run a block using a MonadLogger instance which writes tuples to an unbounded channel.

The tuples can be extracted (ie. in another thread) with unChanLoggingT or a custom extraction funtion, and written to a destination.

valuerunFileLoggingT :: MonadBaseControl IO m => FilePath -> LoggingT m a -> m a

Run a block using a MonadLogger instance which appends to the specified file.

valueunChanLoggingT :: (MonadLogger m, MonadIO m) => Chan LogLine -> m void

Read logging tuples from an unbounded channel and log them into a MonadLoggerIO monad, forever.

For use in a dedicated thread with a channel fed by runChanLoggingT.

valuewithChannelLogger

:: (MonadBaseControl IO m, MonadIO m)
=> Int
Number of messages to keep
-> LoggingT m a
-> LoggingT m a

Within the LoggingT monad, capture all log messages to a bounded channel of the indicated size, and only actually log them if there is an exception.

valuefilterLogger

:: LogSource -> LogLevel -> Bool
-> LoggingT m a
-> LoggingT m a

Only log messages passing the given predicate function.

This can be a convenient way, for example, to ignore debug level messages.

newtypenewtype NoLoggingT (m :: Type -> Type) a

Monad transformer that disables logging.

Constructors

NoLoggingT
- runNoLoggingT :: m a

Instances27MonadTrans, MonadTransControl, MonadAccum, MonadError, MonadReader, MonadState, …

MonadTrans NoLoggingTDefined in monad-logger-0.3.42 · Control.Monad.Logger
MonadTransControl NoLoggingTDefined in monad-logger-0.3.42 · Control.Monad.Logger
MonadAccum w m => MonadAccum w (NoLoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadError e m => MonadError e (NoLoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadReader r m => MonadReader r (NoLoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadState s m => MonadState s (NoLoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadWriter w m => MonadWriter w (NoLoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadBase b m => MonadBase b (NoLoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadBaseControl b m => MonadBaseControl b (NoLoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
Monad m => Monad (NoLoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
Functor m => Functor (NoLoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadFail m => MonadFail (NoLoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
Applicative m => Applicative (NoLoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
Alternative m => Alternative (NoLoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadIO m => MonadIO (NoLoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadCatch m => MonadCatch (NoLoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadMask m => MonadMask (NoLoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadThrow m => MonadThrow (NoLoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadUnliftIO m => MonadUnliftIO (NoLoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadResource m => MonadResource (NoLoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadActive m => MonadActive (NoLoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
Monad m => MonadLogger (NoLoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadIO m => MonadLoggerIO (NoLoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
(Applicative m, Semigroup a) => Semigroup (NoLoggingT m a)Defined in monad-logger-0.3.42 · Control.Monad.Logger
(Applicative m, Monoid a) => Monoid (NoLoggingT m a)Defined in monad-logger-0.3.42 · Control.Monad.Logger
type StM (NoLoggingT m) a = StM m aDefined in monad-logger-0.3.42 · Control.Monad.Logger
type StT NoLoggingT a = aDefined in monad-logger-0.3.42 · Control.Monad.Logger

valuemapNoLoggingT :: (m a -> n b) -> NoLoggingT m a -> NoLoggingT n b

Map the unwrapped computation using the given function.

newtypenewtype WriterLoggingT (m :: Type -> Type) a

Constructors

WriterLoggingT
- unWriterLoggingT :: m (a, DList LogLine)

Instances16MonadTrans, MonadTransControl, MonadBase, MonadBaseControl, Monad, Functor, …

MonadTrans WriterLoggingTDefined in monad-logger-0.3.42 · Control.Monad.Logger
MonadTransControl WriterLoggingTDefined in monad-logger-0.3.42 · Control.Monad.Logger
MonadBase b m => MonadBase b (WriterLoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadBaseControl b m => MonadBaseControl b (WriterLoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
Monad m => Monad (WriterLoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
Functor m => Functor (WriterLoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
Applicative m => Applicative (WriterLoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadIO m => MonadIO (WriterLoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadCatch m => MonadCatch (WriterLoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadMask m => MonadMask (WriterLoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
MonadThrow m => MonadThrow (WriterLoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
Monad m => MonadLogger (WriterLoggingT m)Defined in monad-logger-0.3.42 · Control.Monad.Logger
(Applicative m, Semigroup a) => Semigroup (WriterLoggingT m a)Defined in monad-logger-0.3.42 · Control.Monad.Logger
(Applicative m, Monoid a) => Monoid (WriterLoggingT m a)Defined in monad-logger-0.3.42 · Control.Monad.Logger
type StM (WriterLoggingT m) a = ComposeSt WriterLoggingT m aDefined in monad-logger-0.3.42 · Control.Monad.Logger
type StT WriterLoggingT a = (a, DList LogLine)Defined in monad-logger-0.3.42 · Control.Monad.Logger

valueexecWriterLoggingT :: Functor m => WriterLoggingT m a -> m [LogLine]

Run a block using a MonadLogger instance. Return logs in a list | @since 0.3.28

valuerunWriterLoggingT :: Functor m => WriterLoggingT m a -> m (a, [LogLine])

Run a block using a MonadLogger instance. Return a value and logs in a list | @since 0.3.28

valuemapLoggingT :: (m a -> n b) -> LoggingT m a -> LoggingT n b

Map the unwrapped computation using the given function.

TH logging

5 declarations

valuelogDebug :: Q Exp

Generates a function that takes a Text and logs a LevelDebug message. Usage:

$(logDebug) "This is a debug log message"

valuelogInfo :: Q Exp

See logDebug

valuelogWarn :: Q Exp

See logDebug

valuelogError :: Q Exp

See logDebug

valuelogOther :: Text -> Q Exp

Generates a function that takes a Text and logs a LevelOther message. Usage:

$(logOther "My new level") "This is a log message"

TH logging of showable values

5 declarations

valuelogDebugSH :: Q Exp

Generates a function that takes a 'Show a => a' and logs a LevelDebug message. Usage:

$(logDebugSH) (Just "This is a debug log message")

valuelogInfoSH :: Q Exp

See logDebugSH

valuelogWarnSH :: Q Exp

See logDebugSH

valuelogErrorSH :: Q Exp

See logDebugSH

valuelogOtherSH :: Text -> Q Exp

Generates a function that takes a 'Show a => a' and logs a LevelOther message. Usage:

$(logOtherSH "My new level") "This is a log message"

TH logging with source

5 declarations

valuelogDebugS :: Q Exp

Generates a function that takes a LogSource and Text and logs a LevelDebug message. Usage:

$logDebugS "SomeSource" "This is a debug log message"

valuelogInfoS :: Q Exp

See logDebugS

valuelogWarnS :: Q Exp

See logDebugS

valuelogErrorS :: Q Exp

See logDebugS

valuelogOtherS :: Q Exp

Generates a function that takes a LogSource, a level name and a Text and logs a LevelOther message. Usage:

$logOtherS "SomeSource" "My new level" "This is a log message"

TH util

1 declaration

valueliftLoc :: Loc -> Q Exp

Lift a location into an Exp.

Non-TH logging

5 declarations

valuelogDebugN :: MonadLogger m => Text -> m ()

valuelogInfoN :: MonadLogger m => Text -> m ()

valuelogWarnN :: MonadLogger m => Text -> m ()

valuelogErrorN :: MonadLogger m => Text -> m ()

valuelogOtherN :: MonadLogger m => LogLevel -> Text -> m ()

Non-TH logging with source

6 declarations

valuelogWithoutLoc

:: (MonadLogger m, ToLogStr msg)
=> LogSource
-> LogLevel
-> msg
-> m ()

valuelogDebugNS :: MonadLogger m => LogSource -> Text -> m ()

valuelogInfoNS :: MonadLogger m => LogSource -> Text -> m ()

valuelogWarnNS :: MonadLogger m => LogSource -> Text -> m ()

valuelogErrorNS :: MonadLogger m => LogSource -> Text -> m ()

valuelogOtherNS :: MonadLogger m => LogSource -> LogLevel -> Text -> m ()

Callstack logging

5 declarations

valuelogDebugCS :: MonadLogger m => CallStack -> Text -> m ()

Logs a message with location given by CallStack. See CallStack for more convenient functions for CallStack based logging.

valuelogInfoCS :: MonadLogger m => CallStack -> Text -> m ()

See logDebugCS

valuelogWarnCS :: MonadLogger m => CallStack -> Text -> m ()

See logDebugCS

valuelogErrorCS :: MonadLogger m => CallStack -> Text -> m ()

See logDebugCS

valuelogOtherCS :: MonadLogger m => CallStack -> LogLevel -> Text -> m ()

See logDebugCS

utilities for defining your own loggers

4 declarations

valuedefaultLogStr :: Loc -> LogSource -> LogLevel -> LogStr -> LogStr

Loc

When monad-logger is compiled with the template_haskell flag set to true (the default), the Loc below is a re-export from the template-haskell package. When the flag is false, the Loc below is a copy of that data structure defined in monad-logger itself.

If you are making a library that:

Uses monad-logger
Uses Loc in a type signature
But doesn't need to depend on template-haskell for other reasons

You can import Loc directly from this package, instead of adding an dependency on template-haskell and importing from there. This allows users to compile your package in environments that don't support template-haskell.

datadata Loc

Constructors

Loc
- loc_filename :: String
- loc_package :: String
- loc_module :: String
- loc_start :: CharPos
- loc_end :: CharPos

Instances7Eq, Data, Ord, Show, Generic, Ppr, …

Eq LocDefined in template-haskell-2.22.0.0 · Language.Haskell.TH.Syntax
Data LocDefined in template-haskell-2.22.0.0 · Language.Haskell.TH.Syntax
Ord LocDefined in template-haskell-2.22.0.0 · Language.Haskell.TH.Syntax
Show LocDefined in template-haskell-2.22.0.0 · Language.Haskell.TH.Syntax
Generic LocDefined in template-haskell-2.22.0.0 · Language.Haskell.TH.Syntax
Ppr LocDefined in template-haskell-2.22.0.0 · Language.Haskell.TH.Ppr
type Rep Loc = D1 ('MetaData "Loc" "Language.Haskell.TH.Syntax" "template-haskell" 'False) (C1 ('MetaCons "Loc" 'PrefixI 'True) ((S1 ('MetaSel ('Just "loc_filename") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 String) :*: S1 ('MetaSel ('Just "loc_package") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 String)) :*: (S1 ('MetaSel ('Just "loc_module") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 String) :*: (S1 ('MetaSel ('Just "loc_start") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 CharPos) :*: S1 ('MetaSel ('Just "loc_end") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 CharPos)))))Defined in template-haskell-2.22.0.0 · Language.Haskell.TH.Syntax

valuedefaultLoc :: Loc

dummy location, used with logWithoutLoc

valuedefaultOutput :: Handle -> Loc -> LogSource -> LogLevel -> LogStr -> IO ()

A default implementation of monadLoggerLog that accepts a file handle as the first argument.

This is used in the definition of runStdoutLoggingT:

runStdoutLoggingT :: MonadIO m => LoggingT m a -> m a
runStdoutLoggingT action =
    runLoggingT action (defaultOutput stdout)