Developing on Windows¶
On Windows, Stack comes with an installation of MSYS2.
MSYS2 will be used by Stack to provide a Unix-like shell and environment for
Stack. This may be necessary for installing some Haskell packages, such as those
which use configure
scripts, or if your project needs some additional tools
during the build phase.
No matter which terminal software you choose (Windows Terminal, Console Windows
Host, Command Prompt, PowerShell, Git bash or any other) you can use this
environment too by executing all programs through
stack exec -- <program_name>
.
Executables and libraries can be installed with the MSYS2 package manager
pacman
. All tools can be found in the index to
MSYS2 packages. A guide to
package management with pacman
is also available. pacman
— like all
other tools in the Stack environment — should be started with
stack exec -- pacman
. Help about pacman
commands (operations) can be
obtained by stack exec -- pacman --help
. Help about a specific pacman
operation can be obtained by using --help
(or -h
) with an operation. For
example, help about the operation --sync
(or -S
) can be obtained with
stack exec -- pacman --sync --help
or, equivalently,
stack exec -- pacman -Sh
.
Command stack path --bin-path
to see the PATH in the Stack environment. On
Windows, it includes the \mingw64\bin
, \usr\bin
and \usr\local\bin
directories of the Stack-supplied MSYS2. If your executable depends on files
(for example, dynamic-link libraries) in those directories and you want ro run
it outside of the Stack environment, you will need to ensure copies of those
files are on the PATH.
Updating the Stack-supplied MSYS2¶
The Stack-supplied MSYS2 can itself be updated with the Stack-supplied pacman
.
See the MSYS2 guide Updating MSYS2. If
the Stack-supplied pacman
has a version that is 5.0.1.6403 or greater (see
stack exec -- pacman --version
) then the command to update is simply:
stack exec -- pacman -Suy
This command may need to be run more than once, until everything is reported by
pacman
as 'up to date' and 'nothing to do'.
Setup.hs¶
Setup.hs
is automatically run inside the Stack environment. So when you need
to launch another tool you don't need to prefix the command with stack exec --
within the custom Setup.hs
file.
Pacman packages to install for common Haskell packages¶
The following lists MSYS2 packages known to allow the installation of some common Haskell packages on Windows. Feel free to submit additional entries via a pull request.
- For text-icu install
mingw64/mingw-w64-x86_64-icu
CMake¶
CMake has trouble finding other tools even if they are available on the PATH.
Likely this is not a CMake problem but one of the environment not fully
integrating. For example GHC comes with a copy of GCC which is not installed by
MSYS2 itself. If you want to use this GCC you can provide a full path to it, or
find it first with System.Directory.findExecutable
if you want to launch GCC
from a Haskell file such as Setup.hs
.
Experience tells that the mingw-w64
versions of Make and CMake are most
likely to work. Though there are other versions available through pacman
, so
have a look to see what works for you. Both tools can be installed with the
commands:
stack exec -- pacman -S mingw-w64-x86_64-make
stack exec -- pacman -S mingw-w64-x86_64-cmake
Even though Make and CMake are then both installed into the same environment, CMake still seems to have trouble to find Make. To help CMake find GCC and Make supply the following flags:
-DCMAKE_C_COMPILER=path
-DCMAKE_MAKE_PROGRAM=path