Distribution.Simple.Utils

A large and somewhat miscellaneous collection of utility functions used throughout the rest of the Cabal lib and in other tools that use the Cabal lib like cabal-install. It has a very simple set of logging actions. It has low level functions for running programs, a bunch of wrappers for various directory and file functions that do extra logging.

Documentation

cabalVersion :: Version

logging and errors

dieNoVerbosity :: String -> IO a

die' :: Verbosity -> String -> IO a

dieWithException :: (HasCallStack, Show a1, Typeable a1, Exception (VerboseException a1)) => Verbosity -> a1 -> IO a

dieWithLocation' :: Verbosity -> FilePath -> Maybe Int -> String -> IO a

dieNoWrap :: Verbosity -> String -> IO a

topHandler :: IO a -> IO a

topHandlerWith :: forall a. (SomeException -> IO a) -> IO a -> IO a

warn :: Verbosity -> String -> IO ()

Non fatal conditions that may be indicative of an error or problem.

We display these at the normal verbosity level.

warnError :: Verbosity -> String -> IO ()

Like warn, but prepend Error: … instead of Waring: … before the the message. Useful when you want to highlight the condition is an error but do not want to quit the program yet.

notice :: Verbosity -> String -> IO ()

Useful status messages.

We display these at the normal verbosity level.

This is for the ordinary helpful status messages that users see. Just enough information to know that things are working but not floods of detail.

noticeNoWrap :: Verbosity -> String -> IO ()

Display a message at normal verbosity level, but without wrapping.

noticeDoc :: Verbosity -> Doc -> IO ()

Pretty-print a Doc status message at normal verbosity level. Use this if you need fancy formatting.

setupMessage :: Verbosity -> String -> PackageIdentifier -> IO ()

Display a "setup status message". Prefer using setupMessage' if possible.

info :: Verbosity -> String -> IO ()

More detail on the operation of some action.

We display these messages when the verbosity level is verbose

infoNoWrap :: Verbosity -> String -> IO ()

debug :: Verbosity -> String -> IO ()

Detailed internal debugging information

We display these messages when the verbosity level is deafening

debugNoWrap :: Verbosity -> String -> IO ()

A variant of debug that doesn't perform the automatic line wrapping. Produces better output in some cases.

chattyTry

Arguments

:: String

a description of the action we were attempting

-> IO ()

the action itself

-> IO ()

Perform an IO action, catching any IO exceptions and printing an error if one occurs.

annotateIO :: Verbosity -> IO a -> IO a

Given a block of IO code that may raise an exception, annotate it with the metadata from the current scope. Use this as close to external code that raises IO exceptions as possible, since this function unconditionally wraps the error message with a trace (so it is NOT idempotent.)

exceptionWithMetadata :: CallStack -> POSIXTime -> Verbosity -> String -> String

Add all necessary metadata to a logging message

withOutputMarker :: Verbosity -> String -> String

Wrap output with a marker if +markoutput verbosity flag is set.

NB: Why is markoutput done with start/end markers, and not prefixes? Markers are more convenient to add (if we want to add prefixes, we have to lines and then map; here's it's just some concatenates). Note that even in the prefix case, we can't guarantee that the markers are unambiguous, because some of Cabal's output comes straight from external programs, where we don't have the ability to interpose on the output.

This is used by withMetadata

exceptions

handleDoesNotExist :: a -> IO a -> IO a

Run an IO computation, returning e if it raises a "file does not exist" error.

ignoreSigPipe :: IO () -> IO ()

Ignore SIGPIPE in a subcomputation.

running programs

rawSystemExit :: Verbosity -> Maybe (SymbolicPath CWD (Dir Pkg)) -> FilePath -> [String] -> IO ()

Execute the given command with the given arguments, exiting with the same exit code if the command fails.

rawSystemExitCode :: Verbosity -> Maybe (SymbolicPath CWD (Dir Pkg)) -> FilePath -> [String] -> Maybe [(String, String)] -> IO ExitCode

Execute the given command with the given arguments, returning the command's exit code.

rawSystemProc :: Verbosity -> CreateProcess -> IO ExitCode

Execute the given command with the given arguments, returning the command's exit code.

Create the process argument with proc to ensure consistent options with other rawSystem functions in this module.

rawSystemProcAction :: Verbosity -> CreateProcess -> (Maybe Handle -> Maybe Handle -> Maybe Handle -> IO a) -> IO (ExitCode, a)

Execute the given command with the given arguments, returning the command's exit code. action is executed while the command is running, and would typically be used to communicate with the process through pipes.

Create the process argument with proc to ensure consistent options with other rawSystem functions in this module.

rawSystemExitWithEnv :: Verbosity -> FilePath -> [String] -> [(String, String)] -> IO ()

Execute the given command with the given arguments and environment, exiting with the same exit code if the command fails.

rawSystemExitWithEnvCwd :: Verbosity -> Maybe (SymbolicPath CWD to) -> FilePath -> [String] -> [(String, String)] -> IO ()

Like rawSystemExitWithEnv, but setting a working directory.

rawSystemStdout :: forall mode. KnownIODataMode mode => Verbosity -> FilePath -> [String] -> IO mode

Execute the given command with the given arguments, returning the command's output. Exits if the command exits with error.

Provides control over the binary/text mode of the output.

rawSystemStdInOut

Arguments

:: KnownIODataMode mode

=> Verbosity

-> FilePath

Program location

-> [String]

Arguments

-> Maybe FilePath

New working dir or inherit

-> Maybe [(String, String)]

New environment or inherit

-> Maybe IOData

input text and binary mode

-> IODataMode mode

iodata mode, acts as proxy

-> IO (mode, String, ExitCode)

output, errors, exit

Execute the given command with the given arguments, returning the command's output, errors and exit code.

Optional arguments allow setting working directory, environment and command input.

Provides control over the binary/text mode of the input and output.

rawSystemIOWithEnv

Arguments

:: Verbosity

-> FilePath

-> [String]

-> Maybe FilePath

New working dir or inherit

-> Maybe [(String, String)]

New environment or inherit

-> Maybe Handle

stdin

-> Maybe Handle

stdout

-> Maybe Handle

stderr

-> IO ExitCode

Execute the given command with the given arguments, returning the command's exit code.

Optional arguments allow setting working directory, environment and input and output handles.

rawSystemIOWithEnvAndAction

Arguments

:: Verbosity

-> FilePath

-> [String]

-> Maybe FilePath

New working dir or inherit

-> Maybe [(String, String)]

New environment or inherit

-> IO a

action to perform after process is created, but before waitForProcess.

-> Maybe Handle

stdin

-> Maybe Handle

stdout

-> Maybe Handle

stderr

-> IO (ExitCode, a)

Execute the given command with the given arguments, returning the command's exit code. action is executed while the command is running, and would typically be used to communicate with the process through pipes.

Optional arguments allow setting working directory, environment and input and output handles.

fromCreatePipe :: Maybe Handle -> Handle

fromJust for dealing with 'Maybe Handle' values as obtained via CreatePipe. Creating a pipe using CreatePipe guarantees a Just value for the corresponding handle.

maybeExit :: IO ExitCode -> IO ()

Helper to use with one of the rawSystem variants, and exit unless the command completes successfully.

xargs :: Int -> ([String] -> IO ()) -> [String] -> [String] -> IO ()

Like the Unix xargs program. Useful for when we've got very long command lines that might overflow an OS limit on command line length and so you need to invoke a command multiple times to get all the args in.

Use it with either of the rawSystem variants above. For example:

xargs (32*1024) (rawSystemExit verbosity) prog fixedArgs bigArgs

findProgramVersion

Arguments

:: String

version args

-> (String -> String)

function to select version number from program output

-> Verbosity

-> FilePath

location

-> IO (Maybe Version)

Look for a program and try to find it's version number. It can accept either an absolute path or the name of a program binary, in which case we will look for the program on the path.

IOData re-export

data IOData

Represents either textual or binary data passed via I/O functions which support binary/text mode

Since: 2.2

Constructors

IODataText String

How Text gets encoded is usually locale-dependent.

IODataBinary ByteString

Raw binary which gets read/written in binary mode.

Instances

NFData IOData

Defined in Distribution.Utils.IOData

Methods

rnf :: IOData -> ()

class NFData mode => KnownIODataMode mode where

Since: 2.2

Methods

hGetIODataContents :: Handle -> IO mode

IOData Wrapper for hGetContents

Note: This operation uses lazy I/O. Use NFData to force all data to be read and consequently the internal file handle to be closed.

toIOData :: mode -> IOData

iodataMode :: IODataMode mode

Instances

KnownIODataMode ByteString

Defined in Distribution.Utils.IOData

Methods

hGetIODataContents :: Handle -> IO ByteString

toIOData :: ByteString -> IOData

iodataMode :: IODataMode ByteString

a ~ Char => KnownIODataMode [a]

Defined in Distribution.Utils.IOData

Methods

hGetIODataContents :: Handle -> IO [a]

toIOData :: [a] -> IOData

iodataMode :: IODataMode [a]

data IODataMode mode where

Phantom-typed GADT representation of the mode of IOData, containing no other data.

Since: 3.2

Constructors

IODataModeText :: IODataMode String

IODataModeBinary :: IODataMode ByteString

data VerboseException a

Constructors

VerboseException CallStack POSIXTime Verbosity a

Instances

Exception (VerboseException CabalException)

Defined in Distribution.Simple.Utils

Methods

toException :: VerboseException CabalException -> SomeException

fromException :: SomeException -> Maybe (VerboseException CabalException)

displayException :: VerboseException CabalException -> String

Show a => Show (VerboseException a)

Defined in Distribution.Simple.Utils

Methods

showsPrec :: Int -> VerboseException a -> ShowS

show :: VerboseException a -> String

showList :: [VerboseException a] -> ShowS

copying files

createDirectoryIfMissingVerbose

Arguments

:: Verbosity

-> Bool

Create its parents too?

-> FilePath

-> IO ()

Same as createDirectoryIfMissing but logs at higher verbosity levels.

copyFileVerbose :: Verbosity -> FilePath -> FilePath -> IO ()

Copies a file without copying file permissions. The target file is created with default permissions. Any existing target file is replaced.

At higher verbosity levels it logs an info message.

copyFiles :: Verbosity -> FilePath -> [(FilePath, FilePath)] -> IO ()

Copies a bunch of files to a target directory, preserving the directory structure in the target location. The target directories are created if they do not exist.

The files are identified by a pair of base directory and a path relative to that base. It is only the relative part that is preserved in the destination.

For example:

copyFiles normal "dist/src"
   [("", "src/Foo.hs"), ("dist/build/", "src/Bar.hs")]

This would copy "src/Foo.hs" to "dist/src/src/Foo.hs" and copy "dist/build/src/Bar.hs" to "dist/src/src/Bar.hs".

This operation is not atomic. Any IO failure during the copy (including any missing source files) leaves the target in an unknown state so it is best to use it with a freshly created directory so that it can be simply deleted if anything goes wrong.

copyFileTo :: Verbosity -> FilePath -> FilePath -> IO ()

Given a relative path to a file, copy it to the given directory, preserving the relative path and creating the parent directories if needed.

copyFileToCwd :: Verbosity -> Maybe (SymbolicPath CWD (Dir Pkg)) -> SymbolicPath Pkg (Dir target) -> RelativePath Pkg File -> IO ()

Given a relative path to a file, copy it to the given directory, preserving the relative path and creating the parent directories if needed.

installing files

installOrdinaryFile :: Verbosity -> FilePath -> FilePath -> IO ()

Install an ordinary file. This is like a file copy but the permissions are set appropriately for an installed file. On Unix it is "-rw-r--r--" while on Windows it uses the default permissions for the target directory.

installExecutableFile :: Verbosity -> FilePath -> FilePath -> IO ()

Install an executable file. This is like a file copy but the permissions are set appropriately for an installed file. On Unix it is "-rwxr-xr-x" while on Windows it uses the default permissions for the target directory.

installMaybeExecutableFile :: Verbosity -> FilePath -> FilePath -> IO ()

Install a file that may or not be executable, preserving permissions.

installOrdinaryFiles :: Verbosity -> FilePath -> [(FilePath, FilePath)] -> IO ()

This is like copyFiles but uses installOrdinaryFile.

installExecutableFiles :: Verbosity -> FilePath -> [(FilePath, FilePath)] -> IO ()

This is like copyFiles but uses installExecutableFile.

installMaybeExecutableFiles :: Verbosity -> FilePath -> [(FilePath, FilePath)] -> IO ()

This is like copyFiles but uses installMaybeExecutableFile.

installDirectoryContents :: Verbosity -> FilePath -> FilePath -> IO ()

This installs all the files in a directory to a target location, preserving the directory layout. All the files are assumed to be ordinary rather than executable files.

copyDirectoryRecursive :: Verbosity -> FilePath -> FilePath -> IO ()

Recursively copy the contents of one directory to another path.

File permissions

doesExecutableExist :: FilePath -> IO Bool

Like doesFileExist, but also checks that the file is executable.

setFileOrdinary :: FilePath -> IO ()

setFileExecutable :: FilePath -> IO ()

file names

shortRelativePath :: FilePath -> FilePath -> FilePath

dropExeExtension :: FilePath -> FilePath

Drop the extension if it's one of exeExtensions, or return the path unchanged.

exeExtensions :: [String]

List of possible executable file extensions on the current build platform.

finding files

findFileEx

Arguments

:: forall searchDir allowAbsolute. Verbosity

-> [SymbolicPathX allowAbsolute Pkg (Dir searchDir)]

search directories

-> RelativePath searchDir File

File Name

-> IO (SymbolicPathX allowAbsolute Pkg File)

Find a file by looking in a search path. The file path must match exactly.

findFileCwd

Arguments

:: forall searchDir allowAbsolute. Verbosity

-> Maybe (SymbolicPath CWD (Dir Pkg))

working directory

-> [SymbolicPathX allowAbsolute Pkg (Dir searchDir)]

search directories

-> RelativePath searchDir File

File Name

-> IO (SymbolicPathX allowAbsolute Pkg File)

Find a file by looking in a search path. The file path must match exactly.

Since: 3.4.0.0

findFirstFile :: (a -> FilePath) -> [a] -> IO (Maybe a)

newtype Suffix

A suffix (or file extension).

Mostly used to decide which preprocessor to use, e.g. files with suffix "y" are usually processed by the "happy" build tool.

Constructors

Suffix String

Instances

Pretty Suffix

Defined in Distribution.Simple.PreProcess.Types

Methods

pretty :: Suffix -> Doc

prettyVersioned :: CabalSpecVersion -> Suffix -> Doc

Structured Suffix

Defined in Distribution.Simple.PreProcess.Types

Methods

structure :: Proxy Suffix -> Structure

structureHash' :: Tagged Suffix MD5

IsString Suffix

Defined in Distribution.Simple.PreProcess.Types

Methods

fromString :: String -> Suffix

Generic Suffix

Defined in Distribution.Simple.PreProcess.Types

Associated Types

type Rep Suffix :: Type -> Type

Methods

from :: Suffix -> Rep Suffix x

to :: Rep Suffix x -> Suffix

Show Suffix

Defined in Distribution.Simple.PreProcess.Types

Methods

showsPrec :: Int -> Suffix -> ShowS

show :: Suffix -> String

showList :: [Suffix] -> ShowS

Binary Suffix

Defined in Distribution.Simple.PreProcess.Types

Methods

put :: Suffix -> Put

get :: Get Suffix

putList :: [Suffix] -> Put

Eq Suffix

Defined in Distribution.Simple.PreProcess.Types

Methods

(==) :: Suffix -> Suffix -> Bool

(/=) :: Suffix -> Suffix -> Bool

Ord Suffix

Defined in Distribution.Simple.PreProcess.Types

Methods

compare :: Suffix -> Suffix -> Ordering

(<) :: Suffix -> Suffix -> Bool

(<=) :: Suffix -> Suffix -> Bool

(>) :: Suffix -> Suffix -> Bool

(>=) :: Suffix -> Suffix -> Bool

max :: Suffix -> Suffix -> Suffix

min :: Suffix -> Suffix -> Suffix

type Rep Suffix

Defined in Distribution.Simple.PreProcess.Types

type Rep Suffix = D1 ('MetaData "Suffix" "Distribution.Simple.PreProcess.Types" "Cabal-3.14.0.0-inplace" 'True) (C1 ('MetaCons "Suffix" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 String)))

findFileWithExtension :: [Suffix] -> [SymbolicPathX allowAbsolute Pkg (Dir searchDir)] -> RelativePath searchDir File -> IO (Maybe (SymbolicPathX allowAbsolute Pkg File))

Find a file by looking in a search path with one of a list of possible file extensions. The file base name should be given and it will be tried with each of the extensions in each element of the search path.

findFileCwdWithExtension :: forall searchDir allowAbsolute. Maybe (SymbolicPath CWD (Dir Pkg)) -> [Suffix] -> [SymbolicPathX allowAbsolute Pkg (Dir searchDir)] -> RelativePath searchDir File -> IO (Maybe (SymbolicPathX allowAbsolute Pkg File))

Find a file by looking in a search path with one of a list of possible file extensions.

Since: 3.4.0.0

findFileWithExtension' :: [Suffix] -> [SymbolicPathX allowAbsolute Pkg (Dir searchDir)] -> RelativePath searchDir File -> IO (Maybe (SymbolicPathX allowAbsolute Pkg (Dir searchDir), RelativePath searchDir File))

Like findFileWithExtension but returns which element of the search path the file was found in, and the file path relative to that base directory.

findFileCwdWithExtension' :: forall searchDir allowAbsolute. Maybe (SymbolicPath CWD (Dir Pkg)) -> [Suffix] -> [SymbolicPathX allowAbsolute Pkg (Dir searchDir)] -> RelativePath searchDir File -> IO (Maybe (SymbolicPathX allowAbsolute Pkg (Dir searchDir), RelativePath searchDir File))

Like findFileCwdWithExtension but returns which element of the search path the file was found in, and the file path relative to that base directory.

findAllFilesWithExtension :: [Suffix] -> [SymbolicPathX allowAbsolute Pkg (Dir searchDir)] -> RelativePath searchDir File -> IO [SymbolicPathX allowAbsolute Pkg File]

findAllFilesCwdWithExtension

Arguments

:: forall searchDir allowAbsolute. Maybe (SymbolicPath CWD (Dir Pkg))

working directory

-> [Suffix]

extensions

-> [SymbolicPathX allowAbsolute Pkg (Dir searchDir)]

relative search locations

-> RelativePath searchDir File

basename

-> IO [SymbolicPathX allowAbsolute Pkg File]

Since: 3.4.0.0

findModuleFileEx

Arguments

:: forall searchDir allowAbsolute. Verbosity

-> [SymbolicPathX allowAbsolute Pkg (Dir searchDir)]

build prefix (location of objects)

-> [Suffix]

search suffixes

-> ModuleName

module

-> IO (SymbolicPathX allowAbsolute Pkg (Dir searchDir), RelativePath searchDir File)

Find the file corresponding to a Haskell module name.

This is similar to findFileWithExtension' but specialised to a module name. The function fails if the file corresponding to the module is missing.

findModuleFileCwd

Arguments

:: forall searchDir allowAbsolute. Verbosity

-> Maybe (SymbolicPath CWD (Dir Pkg))

-> [SymbolicPathX allowAbsolute Pkg (Dir searchDir)]

build prefix (location of objects)

-> [Suffix]

search suffixes

-> ModuleName

module

-> IO (SymbolicPathX allowAbsolute Pkg (Dir searchDir), RelativePath searchDir File)

Find the file corresponding to a Haskell module name.

This is similar to findFileCwdWithExtension' but specialised to a module name. The function fails if the file corresponding to the module is missing.

findModuleFilesEx

Arguments

:: forall searchDir allowAbsolute. Verbosity

-> [SymbolicPathX allowAbsolute Pkg (Dir searchDir)]

build prefix (location of objects)

-> [Suffix]

search suffixes

-> [ModuleName]

modules

-> IO [(SymbolicPathX allowAbsolute Pkg (Dir searchDir), RelativePath searchDir File)]

Finds the files corresponding to a list of Haskell module names.

As findModuleFile but for a list of module names.

findModuleFilesCwd

Arguments

:: forall searchDir allowAbsolute. Verbosity

-> Maybe (SymbolicPath CWD (Dir Pkg))

-> [SymbolicPathX allowAbsolute Pkg (Dir searchDir)]

build prefix (location of objects)

-> [Suffix]

search suffixes

-> [ModuleName]

modules

-> IO [(SymbolicPathX allowAbsolute Pkg (Dir searchDir), RelativePath searchDir File)]

Finds the files corresponding to a list of Haskell module names.

As findModuleFileCwd but for a list of module names.

getDirectoryContentsRecursive :: FilePath -> IO [FilePath]

List all the files in a directory and all subdirectories.

The order places files in sub-directories after all the files in their parent directories. The list is generated lazily so is not well defined if the source directory structure changes before the list is used.

environment variables

isInSearchPath :: FilePath -> IO Bool

Is this directory in the system search path?

addLibraryPath :: OS -> [FilePath] -> [(String, String)] -> [(String, String)]

modification time

moreRecentFile :: FilePath -> FilePath -> IO Bool

Compare the modification times of two files to see if the first is newer than the second. The first file must exist but the second need not. The expected use case is when the second file is generated using the first. In this use case, if the result is True then the second file is out of date.

existsAndIsMoreRecentThan :: FilePath -> FilePath -> IO Bool

Like moreRecentFile, but also checks that the first file exists.

temp files and dirs

data TempFileOptions

Advanced options for withTempFile and withTempDirectory.

Constructors

TempFileOptions

Fields

• optKeepTempFiles :: Bool

  Keep temporary files?

defaultTempFileOptions :: TempFileOptions

withTempFile

Arguments

:: FilePath

Temp dir to create the file in

-> String

File name template. See openTempFile.

-> (FilePath -> Handle -> IO a)

-> IO a

Use a temporary filename that doesn't already exist

withTempFileCwd

Arguments

:: Maybe (SymbolicPath CWD (Dir Pkg))

Working directory

-> SymbolicPath Pkg (Dir tmpDir)

Temp dir to create the file in

-> String

File name template. See openTempFile.

-> (SymbolicPath Pkg File -> Handle -> IO a)

-> IO a

Use a temporary filename that doesn't already exist.

withTempFileEx

Arguments

:: forall a tmpDir. TempFileOptions

-> Maybe (SymbolicPath CWD (Dir Pkg))

Working directory

-> SymbolicPath Pkg (Dir tmpDir)

Temp dir to create the file in

-> String

File name template. See openTempFile.

-> (SymbolicPath Pkg File -> Handle -> IO a)

-> IO a

A version of withTempFile that additionally takes a TempFileOptions argument.

withTempDirectory :: Verbosity -> FilePath -> String -> (FilePath -> IO a) -> IO a

Create and use a temporary directory.

Creates a new temporary directory inside the given directory, making use of the template. The temp directory is deleted after use. For example:

withTempDirectory verbosity "src" "sdist." $ \tmpDir -> do ...

The tmpDir will be a new subdirectory of the given directory, e.g. src/sdist.342.

withTempDirectoryCwd

Arguments

:: Verbosity

-> Maybe (SymbolicPath CWD (Dir Pkg))

Working directory

-> SymbolicPath Pkg (Dir tmpDir1)

-> String

-> (SymbolicPath Pkg (Dir tmpDir2) -> IO a)

-> IO a

Create and use a temporary directory.

Creates a new temporary directory inside the given directory, making use of the template. The temp directory is deleted after use. For example:

withTempDirectory verbosity "src" "sdist." $ \tmpDir -> do ...

The tmpDir will be a new subdirectory of the given directory, e.g. src/sdist.342.

withTempDirectoryEx :: Verbosity -> TempFileOptions -> FilePath -> String -> (FilePath -> IO a) -> IO a

A version of withTempDirectory that additionally takes a TempFileOptions argument.

withTempDirectoryCwdEx

Arguments

:: forall a tmpDir1 tmpDir2. Verbosity

-> TempFileOptions

-> Maybe (SymbolicPath CWD (Dir Pkg))

Working directory

-> SymbolicPath Pkg (Dir tmpDir1)

-> String

-> (SymbolicPath Pkg (Dir tmpDir2) -> IO a)

-> IO a

A version of withTempDirectoryCwd that additionally takes a TempFileOptions argument.

createTempDirectory :: FilePath -> String -> IO FilePath

.cabal and .buildinfo files

defaultPackageDescCwd :: Verbosity -> IO (RelativePath Pkg File)

Package description file (pkgname.cabal) in the current working directory.

findPackageDesc

Arguments

:: Maybe (SymbolicPath CWD (Dir Pkg))

package directory

-> IO (Either CabalException (RelativePath Pkg File))

Find a package description file in the given directory. Looks for .cabal files.

tryFindPackageDesc

Arguments

:: Verbosity

-> Maybe (SymbolicPath CWD (Dir Pkg))

directory in which to look

-> IO (RelativePath Pkg File)

Like findPackageDesc, but calls die in case of error.

findHookedPackageDesc

Arguments

:: Verbosity

-> Maybe (SymbolicPath CWD (Dir Pkg))

Working directory

-> SymbolicPath Pkg (Dir Build)

Directory to search

-> IO (Maybe (SymbolicPath Pkg File))

dir/pkgname.buildinfo, if present

Find auxiliary package information in the given directory. Looks for .buildinfo files.

reading and writing files safely

withFileContents :: FilePath -> (String -> IO a) -> IO a

writeFileAtomic :: FilePath -> ByteString -> IO ()

rewriteFileEx :: Verbosity -> FilePath -> String -> IO ()

Write a file but only if it would have new content. If we would be writing the same as the existing content then leave the file as is so that we do not update the file's modification time.

NB: Before Cabal-3.0 the file content was assumed to be ASCII-representable. Since Cabal-3.0 the file is assumed to be UTF-8 encoded.

rewriteFileLBS :: Verbosity -> FilePath -> ByteString -> IO ()

Same as rewriteFileEx but for ByteStrings.

Unicode

fromUTF8BS :: ByteString -> String

fromUTF8LBS :: ByteString -> String

toUTF8BS :: String -> ByteString

toUTF8LBS :: String -> ByteString

readUTF8File :: FilePath -> IO String

withUTF8FileContents :: FilePath -> (String -> IO a) -> IO a

writeUTF8File :: FilePath -> String -> IO ()

normaliseLineEndings :: String -> String

BOM

ignoreBOM :: String -> String

generic utils

dropWhileEndLE :: (a -> Bool) -> [a] -> [a]

takeWhileEndLE :: (a -> Bool) -> [a] -> [a]

equating :: Eq a => (b -> a) -> b -> b -> Bool

comparing :: Ord a => (b -> a) -> b -> b -> Ordering

comparing p x y = compare (p x) (p y)

Useful combinator for use in conjunction with the xxxBy family of functions from Data.List, for example:

  ... sortBy (comparing fst) ...

isInfixOf :: Eq a => [a] -> [a] -> Bool

The isInfixOf function takes two lists and returns True iff the first list is contained, wholly and intact, anywhere within the second.

>>> isInfixOf "Haskell" "I really like Haskell."
True
>>> isInfixOf "Ial" "I really like Haskell."
False

For the result to be True, the first list must be finite; for the result to be False, the second list must be finite:

>>> [20..50] `isInfixOf` [0..]
True
>>> [0..] `isInfixOf` [20..50]
False
>>> [0..] `isInfixOf` [0..]
* Hangs forever *

intercalate :: [a] -> [[a]] -> [a]

intercalate xs xss is equivalent to (concat (intersperse xs xss)). It inserts the list xs in between the lists in xss and concatenates the result.

>>> intercalate ", " ["Lorem", "ipsum", "dolor"]
"Lorem, ipsum, dolor"

lowercase :: String -> String

listUnion :: Ord a => [a] -> [a] -> [a]

listUnionRight :: Ord a => [a] -> [a] -> [a]

ordNub :: Ord a => [a] -> [a]

ordNubBy :: Ord b => (a -> b) -> [a] -> [a]

ordNubRight :: Ord a => [a] -> [a]

safeHead :: [a] -> Maybe a

safeTail :: [a] -> [a]

safeLast :: [a] -> Maybe a

safeInit :: [a] -> [a]

unintersperse :: Char -> String -> [String]

wrapText :: String -> String

wrapLine :: Int -> [String] -> [[String]]

FilePath stuff

isAbsoluteOnAnyPlatform :: FilePath -> Bool

isRelativeOnAnyPlatform :: FilePath -> Bool

exceptionWithCallStackPrefix :: CallStack -> Verbosity -> String -> String

Append a call-site and/or call-stack based on Verbosity