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GHC 10.0.0.20260917 · lts/ghc-10.0.x · 8fef28d · 2026-11-02

ModuleCabal-3.18.1.0Haskell2010

Distribution.Verbosity

A Verbosity type with associated utilities.

There are 4 standard verbosity levels from silent, normal, verbose up to deafening. This is used for deciding what logging messages to print.

Verbosity also is equipped with some internal settings which can be used to control at a fine granularity the verbosity of specific settings (e.g., so that you can trace only particular things you are interested in.) It's important to note that the instances for Verbosity assume that this does not exist.

Contents

Rich verbosity
Verbosity flags
Call stacks
Output markers
Line wrapping
Time stamps
Stderr
No warnings

Synopsis

PackageCabal-3.18.1.0
Exports44
LanguageHaskell2010
LicenceBSD-3-Clause
SourceVerbosity.hs

Rich verbosity

datadata Verbosity

Rich verbosity, used for the Cabal library interface.

Constructors

Verbosity
- verbosityFlags :: VerbosityFlags
- verbosityHandles :: VerbosityHandles

Instances4Generic, NFData, Structured, Rep

Generic VerbosityDefined in Cabal-3.18.1.0 · Distribution.Verbosity
NFData VerbosityDefined in Cabal-3.18.1.0 · Distribution.Verbosity
Structured VerbosityDefined in Cabal-3.18.1.0 · Distribution.Verbosity
type Rep Verbosity = D1 ('MetaData "Verbosity" "Distribution.Verbosity" "Cabal-3.18.1.0-2e60" 'False) (C1 ('MetaCons "Verbosity" 'PrefixI 'True) (S1 ('MetaSel ('Just "verbosityFlags") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 VerbosityFlags) :*: S1 ('MetaSel ('Just "verbosityHandles") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 VerbosityHandles)))Defined in Cabal-3.18.1.0 · Distribution.Verbosity

datadata VerbosityHandles

Handles to use for logging (e.g. log to stdout, or log to a file).

Constructors

VerbosityHandles
- vStdoutHandle :: Handle
- vStderrHandle :: Handle

Instances2NFData, Structured

NFData VerbosityHandlesDefined in Cabal-3.18.1.0 · Distribution.Verbosity
Structured VerbosityHandlesDefined in Cabal-3.18.1.0 · Distribution.Verbosity

valuedefaultVerbosityHandles :: VerbosityHandles

datadata VerbosityLevel

Silent Normal Verbose Deafening

Instances11Bounded, Enum, Eq, Ord, Read, Show, …

Bounded VerbosityLevelDefined in Cabal-3.18.1.0 · Distribution.Verbosity.Internal
Enum VerbosityLevelDefined in Cabal-3.18.1.0 · Distribution.Verbosity.Internal
Eq VerbosityLevelDefined in Cabal-3.18.1.0 · Distribution.Verbosity.Internal
Ord VerbosityLevelDefined in Cabal-3.18.1.0 · Distribution.Verbosity.Internal
Read VerbosityLevelDefined in Cabal-3.18.1.0 · Distribution.Verbosity.Internal
Show VerbosityLevelDefined in Cabal-3.18.1.0 · Distribution.Verbosity.Internal
Generic VerbosityLevelDefined in Cabal-3.18.1.0 · Distribution.Verbosity.Internal
NFData VerbosityLevelDefined in Cabal-3.18.1.0 · Distribution.Verbosity.Internal
Binary VerbosityLevelDefined in Cabal-3.18.1.0 · Distribution.Verbosity.Internal
Structured VerbosityLevelDefined in Cabal-3.18.1.0 · Distribution.Verbosity.Internal
type Rep VerbosityLevel = D1 ('MetaData "VerbosityLevel" "Distribution.Verbosity.Internal" "Cabal-3.18.1.0-2e60" 'False) ((C1 ('MetaCons "Silent" 'PrefixI 'False) U1 :+: C1 ('MetaCons "Normal" 'PrefixI 'False) U1) :+: (C1 ('MetaCons "Verbose" 'PrefixI 'False) U1 :+: C1 ('MetaCons "Deafening" 'PrefixI 'False) U1))Defined in Cabal-3.18.1.0 · Distribution.Verbosity.Internal

valueverbosityLevel :: Verbosity -> VerbosityLevel

valueverbosityChosenOutputHandle :: Verbosity -> Handle

The handle used for normal output.

With the +stderr verbosity flag, this is the error handle.

valueverbosityErrorHandle :: Verbosity -> Handle

The verbosity handle used for error output.

valuemodifyVerbosityFlags

:: VerbosityFlags -> VerbosityFlags
-> Verbosity
-> Verbosity

valuemkVerbosity :: VerbosityHandles -> VerbosityFlags -> Verbosity

valuesetVerbosityHandles :: Maybe Handle -> Verbosity -> Verbosity

Verbosity flags

datadata VerbosityFlags

Verbosity information which can be passed by the CLI.

Instances10Eq, Read, Show, Generic, NFData, Binary, …

Eq VerbosityFlagsDefined in Cabal-3.18.1.0 · Distribution.Verbosity
Read VerbosityFlagsDefined in Cabal-3.18.1.0 · Distribution.Verbosity
Show VerbosityFlagsDefined in Cabal-3.18.1.0 · Distribution.Verbosity
Generic VerbosityFlagsDefined in Cabal-3.18.1.0 · Distribution.Verbosity
NFData VerbosityFlagsDefined in Cabal-3.18.1.0 · Distribution.Verbosity
Binary VerbosityFlagsDefined in Cabal-3.18.1.0 · Distribution.Verbosity

Parsec VerbosityFlagsDefined in Cabal-3.18.1.0 · Distribution.Verbosity

Parser verbosity

Example1 expression

>>> explicitEitherParsec parsecVerbosity "normal"Right (VerbosityFlags {vLevel = Normal, vFlags = fromList [], vQuiet = False})

Example1 expression

>>> explicitEitherParsec parsecVerbosity "normal+nowrap  "Right (VerbosityFlags {vLevel = Normal, vFlags = fromList [VNoWrap], vQuiet = False})

Example1 expression

>>> explicitEitherParsec parsecVerbosity "normal+nowrap +markoutput"Right (VerbosityFlags {vLevel = Normal, vFlags = fromList [VNoWrap,VMarkOutput], vQuiet = False})

Example1 expression

>>> explicitEitherParsec parsecVerbosity "normal +nowrap +markoutput"Right (VerbosityFlags {vLevel = Normal, vFlags = fromList [VNoWrap,VMarkOutput], vQuiet = False})

Example1 expression

>>> explicitEitherParsec parsecVerbosity "normal+nowrap+markoutput"Right (VerbosityFlags {vLevel = Normal, vFlags = fromList [VNoWrap,VMarkOutput], vQuiet = False})

Example1 expression

>>> explicitEitherParsec parsecVerbosity "deafening+nowrap+stdout+stderr+callsite+callstack"Right (VerbosityFlags {vLevel = Deafening, vFlags = fromList [VCallStack,VCallSite,VNoWrap,VStderr], vQuiet = False})

Note: this parser will eat trailing spaces.

Pretty VerbosityFlagsDefined in Cabal-3.18.1.0 · Distribution.Verbosity
Structured VerbosityFlagsDefined in Cabal-3.18.1.0 · Distribution.Verbosity
type Rep VerbosityFlags = D1 ('MetaData "VerbosityFlags" "Distribution.Verbosity" "Cabal-3.18.1.0-2e60" 'False) (C1 ('MetaCons "VerbosityFlags" 'PrefixI 'True) (S1 ('MetaSel ('Just "vLevel") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 VerbosityLevel) :*: (S1 ('MetaSel ('Just "vFlags") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 (Set VerbosityFlag)) :*: S1 ('MetaSel ('Just "vQuiet") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Bool))))Defined in Cabal-3.18.1.0 · Distribution.Verbosity

valuevLevel :: VerbosityFlags -> VerbosityLevel

valuemkVerbosityFlags :: VerbosityLevel -> VerbosityFlags

valuemakeVerbose :: VerbosityFlags -> VerbosityFlags

Make sure the verbosity level is at least verbose, but stay silent if we are.

valuesilent :: VerbosityFlags

In silent mode, we should not print anything unless an error occurs.

valuenormal :: VerbosityFlags

Print stuff we want to see by default.

valueverbose :: VerbosityFlags

Be more verbose about what's going on.

valuedeafening :: VerbosityFlags

Not only are we verbose ourselves (perhaps even noisier than when being verbose), but we tell everything we run to be verbose too.

valuemoreVerbose :: VerbosityFlags -> VerbosityFlags

Increase verbosity level, but stay silent if we are.

valuelessVerbose :: VerbosityFlags -> VerbosityFlags

Decrease verbosity level, but stay deafening if we are.

valueisVerboseQuiet :: VerbosityFlags -> Bool

Test if we had called lessVerbose on the verbosity.

valueintToVerbosity :: Int -> Maybe VerbosityFlags

Numeric verbosity level 0..3: 0 is silent, 3 is deafening.

valueflagToVerbosity :: ReadE VerbosityFlags

valueshowForCabal :: VerbosityFlags -> String

valueshowForGHC :: VerbosityFlags -> String

valueverboseNoFlags :: VerbosityFlags -> VerbosityFlags

Turn off all flags.

valueverboseHasFlags :: VerbosityFlags -> Bool

Call stacks

valueverboseCallSite :: VerbosityFlags -> VerbosityFlags

Turn on verbose call-site printing when we log.

valueverboseCallStack :: VerbosityFlags -> VerbosityFlags

Turn on verbose call-stack printing when we log.

valueisVerboseCallSite :: VerbosityFlags -> Bool

Test if we should output call sites when we log.

valueisVerboseCallStack :: VerbosityFlags -> Bool

Test if we should output call stacks when we log.

Output markers

valueverboseMarkOutput :: VerbosityFlags -> VerbosityFlags

Turn on -----BEGIN CABAL OUTPUT----- markers for output from Cabal (as opposed to GHC, or system dependent).

valueisVerboseMarkOutput :: VerbosityFlags -> Bool

Test if we should output markers.

valueverboseUnmarkOutput :: VerbosityFlags -> VerbosityFlags

Turn off marking; useful for suppressing nondeterministic output.

Line wrapping

valueverboseNoWrap :: VerbosityFlags -> VerbosityFlags

Disable line-wrapping for log messages.

valueisVerboseNoWrap :: VerbosityFlags -> Bool

Test if line-wrapping is disabled for log messages.

Time stamps

valueverboseTimestamp :: VerbosityFlags -> VerbosityFlags

Turn on timestamps for log messages.

valueisVerboseTimestamp :: VerbosityFlags -> Bool

Test if we should output timestamps when we log.

valueverboseNoTimestamp :: VerbosityFlags -> VerbosityFlags

Turn off timestamps for log messages.

Stderr

valueverboseStderr :: VerbosityFlags -> VerbosityFlags

Switch logging to stderr.

valueisVerboseStderr :: VerbosityFlags -> Bool

Test if we should output to stderr when we log.

valueverboseNoStderr :: VerbosityFlags -> VerbosityFlags

Switch logging to stdout.

No warnings

valueverboseNoWarn :: VerbosityFlags -> VerbosityFlags

Turn off warnings for log messages.

valueisVerboseNoWarn :: VerbosityFlags -> Bool

Test if we should output warnings when we log.