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3. Building and installing a package

After you've unpacked a Cabal package, you can build it by moving into the root directory of the package and using the Setup.hs or Setup.lhs script there:

runhaskell Setup.hs [command] [option...]

where runhaskell might be runhugs, runghc or runnhc. The command argument selects a particular step in the build/install process. You can also get a summary of the command syntax with

runhaskell Setup.hs --help

Example 6. Building and installing a system package

runhaskell Setup.hs configure --ghc
runhaskell Setup.hs build
runhaskell Setup.hs install

The first line readies the system to build the tool using GHC; for example, it checks that GHC exists on the system. The second line performs the actual building, while the last both copies the build results to some permanent place and registers the package with GHC.

Example 7. Building and installing a user package

runhaskell Setup.hs configure --ghc --user --prefix=$HOME
runhaskell Setup.hs build
runhaskell Setup.hs install

The package may use packages from the user's package database as well as the global one (--user), is installed under the user's home directory (--prefix), and is registered in the user's package database (--user).

Example 8. Creating a binary package

When creating binary packages (e.g. for RedHat or Debian) one needs to create a tarball that can be sent to another system for unpacking in the root directory:

runhaskell Setup.hs configure --ghc --prefix=/usr
runhaskell Setup.hs build
runhaskell Setup.hs copy --destdir=/tmp/mypkg
(cd /tmp/mypkg; tar cf - .) | gzip -9 >mypkg.tar.gz

If the package contains a library, you need two additional steps:

runhaskell Setup.hs register --gen-script
runhaskell Setup.hs unregister --gen-script

This creates shell scripts register.sh and unregister.sh, which must also be sent to the target system. After unpacking there, the package must be registered by running the register.sh script. The unregister.sh script would be used in the uninstall procedure of the package. Similar steps may be used for creating binary packages for Windows.

The following options are understood by all commands:

--help, -h or -?: List the available options for the command.
--verbose=n or -vn: Set the verbosity level (0-5). The normal level is 1; a missing n defaults to 3.

The various commands and the additional options they support are described below. In the simple build infrastructure, any other options will be reported as errors, except in the case of the configure command.

3.1. setup configure

Prepare to build the package. Typically, this step checks that the target platform is capable of building the package, and discovers platform-specific features that are needed during the build.

The user may also adjust the behaviour of later stages using the options listed in the following subsections. In the simple build infrastructure, the values supplied via these options are recorded in a private file read by later stages.

If a user-supplied configure script is run (see Section 2.3 or Section 2.4), it is passed the --with-hc-pkg, --prefix, --bindir, --libdir, --datadir and --libexecdir options. In addition the value of the --with-compiler option is passed in a --with-hc option and all options specified with --configure-option= are passed on.

3.1.1. Programs used for building

The following options govern the programs used to process the source files of a package:

--ghc or -g, --nhc, --jhc, --hugs

Specify which Haskell implementation to use to build the package. At most one of these flags may be given. If none is given, the implementation under which the setup script was compiled or interpreted is used.

--with-compiler=path or -wpath

Specify the path to a particular compiler. If given, this must match the implementation selected above. The default is to search for the usual name of the selected implementation.

This flag also sets the default value of the --with-hc-pkg option to the package tool for this compiler. Check the output of setup configure -v to ensure that it finds the right package tool (or use --with-hc-pkg explicitly).

--with-hc-pkg=path

Specify the path to the package tool, e.g. ghc-pkg. The package tool must be compatible with the compiler specified by --with-compiler. If this option is omitted, the default value is determined from the compiler selected.

--with-prog=path

Specify the path to the program prog. Any program known to Cabal can be used in place of prog. It can either be a fully path or the name of a program that can be found on the program search path. For example: --with-ghc=ghc-6.6.1 or --with-cpphs=/usr/local/bin/cpphs.

--prog-options=options

Specify additional options to the program prog. Any program known to Cabal can be used in place of prog. For example: --alex-options="--template=mytemplatedir/".

The options is split into program options based on spaces. Any options containing embeded spaced need to be quoted, for example --foo-options='--bar="C:\Program File\Bar"'. As an alternative that takes only one option at a time but avoids the need to quote, use --prog-option instead.

--prog-option=option

Specify a single additional option to the program prog.

For passing an option that contain embeded spaces, such as a file name with embeded spaces, using this rather than --prog-options means you do not need an additional level of quoting. Of course if you are using a command shell you may still need to quote, for example --foo-options="--bar=C:\Program File\Bar".

All of the options passed with either --prog-options or --prog-option are passed in the order they were specified on the configure command line.

3.1.2. Installation paths

The following options govern the location of installed files from a package:

--prefix=dir

The root of the installation, for example /usr/local on a Unix system, or C:\Program Files on a Windows system. The other installation paths are usually subdirectories of prefix, but they don't have to be.

In the simple build system, dir may contain the following path variables: $pkgid $pkg $version $compiler

--bindir=dir

Executables that the user might invoke are installed here.

In the simple build system, dir may contain the following path variables: $prefix $pkgid $pkg $version $compiler

--libdir=dir

Object-code libraries are installed here.

In the simple build system, dir may contain the following path variables: $prefix $bindir $pkgid $pkg $version $compiler

--libexecdir=dir

Executables that are not expected to be invoked directly by the user are installed here.

In the simple build system, dir may contain the following path variables: $prefix $bindir $libdir $libsubdir $pkgid $pkg $version $compiler

--datadir=dir

Architecture-independent data files are installed here.

In the simple build system, dir may contain the following path variables: $prefix $bindir $libdir $libsubdir $pkgid $pkg $version $compiler

In addition the simple build system supports the following installation path options:

--libsubdir=dir

A subdirectory of libdir in which libraries are actually installed. For example, in the simple build system on Unix, the default libdir is /usr/local/lib, and libsubdir contains the package identifier and compiler, e.g. mypkg-0.2/ghc-6.4, so libraries would be installed in /usr/local/lib/mypkg-0.2/ghc-6.4.

dir may contain the following path variables: $pkgid $pkg $version $compiler

--datasubdir=dir

A subdirectory of datadir in which data files are actually installed.

dir may contain the following path variables: $pkgid $pkg $version $compiler

--docdir=dir

Documentation files are installed relative to this directory.

dir may contain the following path variables: $prefix $bindir $libdir $libsubdir $datadir $datasubdir $pkgid $pkg $version $compiler

3.1.2.1. Path variables in the simple build system

For the simple build system, there are a number of variables that can be used when specifying installation paths. The defaults are also specified in terms of these variables. A number of the variables are actually for other paths, like $prefix. This allows paths to be specified relative to each other rather than as absolute paths, which is important for building relocatable packages (see Section 3.1.2.3).

$prefix

The path variable that stands for the root of the installation.

For an installation to be relocatable, all other instllation paths must be relative to the $prefix variable.

$bindir

The path variable that expands to the path given by the --bindir configure option (or the default).

$libdir

As above but for --libdir

$libsubdir

As above but for --libsubdir

$datadir

As above but for --datadir

$datasubdir

As above but for --datasubdir

$docdir

As above but for --docdir

$pkgid

The name and version of the package, eg mypkg-0.2

$pkg

The name of the package, eg mypkg

$version

The version of the package, eg 0.2

$compiler

The compiler being used to build the package, eg ghc-6.6.1

3.1.2.2. Paths in the simple build system

For the simple build system, the following defaults apply:

Option	Windows Default	Unix Default
`--prefix`	`C:\Program Files\Haskell`	`/usr/local`
`--bindir`	`$prefix\bin`	`$prefix/bin`
`--libdir`	`$prefix`	`$prefix/lib`
`--libsubdir` (Hugs)	`hugs\packages\$pkg`	`hugs/packages/$pkg`
`--libsubdir` (others)	`$pkgid\$compiler`	`$pkgid/$compiler`
`--libexecdir`	`$prefix\$pkgid`	`$prefix/libexec`
`--datadir` (executable)	`$prefix`	`$prefix/share`
`--datadir` (library)	`C:\Program Files\Haskell`	`$prefix/share`
`--datasubdir`	`$pkgid`	`$pkgid`
`--docdir`	`$prefix\doc\$pkgid`	`$datadir/doc/$pkgid`

3.1.2.3. Prefix-independence

On Windows, and when using Hugs on any system, it is possible to obtain the pathname of the running program. This means that we can construct an installable executable package that is independent of its absolute install location. The executable can find its auxiliary files by finding its own path and knowing the location of the other files relative to bindir. Prefix-independence is particularly useful: it means the user can choose the install location (i.e. the value of prefix) at install-time, rather than having to bake the path into the binary when it is built.

In order to achieve this, we require that for an executable on Windows, all of bindir, libdir, datadir and libexecdir begin with $prefix. If this is not the case then the compiled executable will have baked in all absolute paths.

The application need do nothing special to achieve prefix-independence. If it finds any files using getDataFileName and the other functions provided for the purpose (see Section 2.2), the files will be accessed relative to the location of the current executable.

A library cannot (currently) be prefix-independent, because it will be linked into an executable whose filesystem location bears no relation to the library package.

3.1.3. Controlling Flag Assignments

If a package descriptions specifies configuration flags (see Section 2.1.5) the package user can control these in several ways. If none of the options below are given, Cabal will try to find a flag assignment in the following way.

For each flag specified, it will assign its default value, evaluate all conditions with this flag assignment, and check if all dependencies can be satisfied. If this check succeeded, the package will be configured with those flag assignments.
If dependencies were missing, the last flag (as by the order in which the flags were introduced in the package description) is tried with its alternative value and so on. This continues until either an assignment is found where all dependencies can be satisfied, or all possible flag assignments have been tried.

If no suitable flag assignment could be found, the configuration phase will fail and a list of missing dependencies will be printed. Note that this resolution process is exponential in the worst case (i.e., in the case where dependencies cannot be satisfied). There are some optimizations applied internally, but the overall complexity remains unchanged.

Flag assignments can be controlled with the following command line options.

-fflagname or -f-flagname: Force the specified flag to true or false (if preceded with a -). Later specifications for the same flags will override earlier, i.e., specifying -fdebug -f-debug is equivalent to -f-debug
--flags=flagspecs: Same as -f, but allows specifying multiple flag assignments at once. The parameter is a space-separated list of flag names (to force a flag to true), optionally preceded by a - (to force a flag to false). For example, --flags="debug -feature1 feature2" is equivalent to -fdebug -f-feature1 -ffeature2.

3.1.4. Miscellaneous options

--user

Allow dependencies to be satisfied by the user package database, in addition to the global database.

This also implies a default of --user for any subsequent install command, as packages registered in the global database should not depend on packages registered in a user's database.

--global

(default) Dependencies must be satisfied by the global package database.

--enable-optimization or -O

(default) Build with optimization flags (if available). This is appropriate for production use, taking more time to build faster libraries and programs.

--disable-optimization

Build without optimization. This is suited for development: building will be quicker, but the resulting library or programs will be slower.

--enable-library-profiling or -p

Request that an additional version of the library with profiling features enabled be built and installed (only for implementations that support profiling).

--disable-library-profiling

(default) Do not generate an additional profiling version of the library.

--enable-executable-profiling

Any executables generated should have profiling enabled (only for implementations that support profiling). For this to work, all libraries used by these executables must also have been built with profiling support.

--disable-executable-profiling

(default) Do not enable profiling in generated executables.

--enable-library-vanilla

(default) Build ordinary libraries (as opposed to profiling libraries). This is independent of the --enable-library-profiling option. If you enable both, you get both.

--disable-library-vanilla

(default) Do not build ordinary libraries. This is useful in conjunction with --enable-library-profiling to build only profiling libraries, rather than profiling and ordinary libraries.

--enable-library-for-ghci

(default) Build libraries suitable for use with GHCi.

--disable-library-for-ghci

Not all platforms support GHCi and indeed on some platforms, trying to build GHCi libs fails. In such cases this flag can be used as a workaround.

--enable-split-objs

Use the GHC -split-objs feature when building the library. This reduces the final size of the executables that use the library by allowing them to link with only the bits that they use rather than the entire library. The downside is that building the library takes longer and uses considerably more memory.

--disable-split-objs

(default) Do not use the GHC -split-objs feature. This makes building the library quicker but the final executables that use the library will be larger.

--enable-shared

Build shared library. This implies a seperate compiler run to generate position independent code as required on most platforms.

--disable-shared

(default) Do not build shared library.

--configure-option=str

An extra option to an external configure script, if one is used (see Section 2.3). There can be several of these options.

In the simple build infrastructure, an additional option is recognized:

--scratchdir=dir: Specify the directory into which the Hugs output will be placed (default: dist/scratch).

3.2. setup build

Perform any preprocessing or compilation needed to make this package ready for installation.

This command takes the following options:

--prog-options=options, --prog-option=option: These are the mostly same as the options configure step (see Section 3.1.1). Unlike the options specified at the configure step, any program options specified at the build step are not persistent but are used for that invocation only. They options specified at the build step are in addition not in replacement of any options specified at the configure step.

3.3. setup makefile

Generate a Makefile that may be used to compile the Haskell modules to object code. This command is currently only supported when building libraries, and only if the compiler is GHC.

The makefile command replaces part of the work done by setup build. The sequence of commands would typeically be:

runhaskell Setup.hs makefile
make
runhaskell Setup.hs build

where setup makefile does the preprocessing, make compiles the Haskell modules, and setup build performs any final steps, such as building the library archives.

The Makefile does not use GHC's --make flag to compile the modules, instead it compiles modules one at a time, using dependency information generated by GHC's -M flag. There are two reasons you might therefore want to use setup makefile:

You want to build in parallel using make -j. Currently, setup build on its own does not support building in parallel.
You want to build an individual module, pass extra flags to a compilation, or do other non-standard things that setup build does not support.

This command takes the following options:

--file=filename or -f filename: Specify the output file (default Makefile).

3.4. setup haddock

Build the documentation for the package using haddock. By default, only the documentation for the exposed modules is generated (see --executables).

This command takes the following options:

--hoogle

Generate a file dist/doc/html/pkgid.txt, which can be converted by Hoogle into a database for searching. This is equivalent to running haddock with the --hoogle flag.

--html-location=url

Specify a template for the location of HTML documentation for pre-requisite packages. The substitutions listed in Section 3.1.2.2 are applied to the template to obtain a location for each package, which will be used by hyperlinks in the generated documentation. For example, the following command generates links pointing at HackageDB pages:

setup haddock --html-location='http://hackage.haskell.org/packages/archive/$pkg/latest/doc/html'

Here the argument is quoted to prevent substitution by the shell.

If this option is omitted, the location for each package is obtained using the package tool (e.g. ghc-pkg).

--executables

Also run haddock for the modules of all the executable programs. By default haddock is run only on the exported modules.

--css=path

The argument path denotes a CSS file, which is passed to haddock and used to set the style of the generated documentation. This is only needed to override the default style that haddock uses.

--hyperlink-source

Generate haddock documentation integrated with HsColour. First, HsColour is run to generate colourised code. Then haddock is run to generate HTML documentation. Each entity shown in the documentation is linked to its definition in the colourised code.

--hscolour-css=path

The argument path denotes a CSS file, which is passed to HsColour as in

runhaskell Setup.hs hscolour --css=path

3.5. setup hscolour

Produce colourised code in HTML format using HsColour. Colourised code for exported modules is put in dist/doc/html/pkgid/src.

This command takes the following options:

--executables: Also run HsColour on the sources of all executable programs. Colourised code is put in dist/doc/html/pkgid/executable/src.
--css=path: Copy the CSS file from path to dist/doc/html/pkgid/src/hscolour.css for exported modules, or to dist/doc/html/pkgid/executable/src/hscolour.css for executable programs. The CSS file defines the actual colours used to colourise code. Note that the hscolour.css file is required for the code to be actually colourised.

3.6. setup install

Copy the files into the install locations and (for library packages) register the package with the compiler, i.e. make the modules it contains available to programs.

The install locations are determined by options to setup configure (see Section 3.1.2).

This command takes the following options:

--global: Register this package in the system-wide database. (This is the default, unless the --user option was supplied to the configure command.)
--user: Register this package in the user's local package database. (This is the default if the --user option was supplied to the configure command.)

3.7. setup copy

Copy the files without registering them. This command is mainly of use to those creating binary packages.

This command takes the following option:

--destdir=path: Specify the directory under which to place installed files. If this is not given, then the root directory is assumed.

3.8. setup register

Register this package with the compiler, i.e. make the modules it contains available to programs. This only makes sense for library packages. Note that the install command incorporates this action. The main use of this separate command is in the post-installation step for a binary package.

This command takes the following options:

--global

--user

--gen-script

Instead of registering the package, generate a script containing commands to perform the registration. On Unix, this file is called register.sh, on Windows, register.bat. This script might be included in a binary bundle, to be run after the bundle is unpacked on the target system.

--gen-pkg-config=[path]

Instead of registering the package, generate a package registration file. This only applies to compilers that support package registration files which at the moment is only GHC. The file should be used with the compiler's mechanism for registering packages.

This option is mainly intended for packaging systems. If possible use the --gen-script option instead since it is more portable across Haskell implementations.

The path is optional and can be used to specify a particular output file to generate. Otherwise, by default the file is the package name and version with a .conf extension.

--inplace

Registers the package for use directly from the build tree, without needing to install it. This can be useful for testing: there's no need to install the package after modifying it, just recompile and test.

This flag does not create a build-tree-local package database. It still registers the package in one of the user or global databases.

However, there are some caveats. It only works with GHC (currently). It only works if your package doesn't depend on having any supplemental files installed - plain Haskell libraries should be fine.

3.9. setup unregister

Deregister this package with the compiler.

This command takes the following options:

--global: Deregister this package in the system-wide database. (This is the default.)
--user: Deregister this package in the user's local package database.
--gen-script: Instead of deregistering the package, generate a script containing commands to perform the deregistration. On Unix, this file is called unregister.sh, on Windows, unregister.bat. This script might be included in a binary bundle, to be run on the target system.

3.10. setup clean

Remove any local files created during the configure, build, haddock, register or unregister steps, and also any files and directories listed in the extra-tmp-files field.

This command takes the following options:

--save-configure or -s: Keeps the configuration information so it is not necessary to run the configure step again before building.

3.11. setup test

Run the test suite specified by the runTests field of Distribution.Simple.UserHooks. See Distribution.Simple for information about creating hooks and using defaultMainWithHooks.

3.12. setup sdist

Create a system- and compiler-independent source distribution in a file package-version.tar.gz in the dist subdirectory, for distribution to package builders. When unpacked, the commands listed in this section will be available.

The files placed in this distribution are the package description file, the setup script, the sources of the modules named in the package description file, and files named in the license-file, main-is, c-sources, data-files and extra-source-files fields.

This command takes the following option:

--snapshot: Append today's date (in YYYYMMDD form) to the version number for the generated source package. The original package is unaffected.

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