How do I get text-icu working on Windows?

Stack includes a copy of msys2 on Windows, which contains the pacman package manager, so we can run:

stack exec -- pacman -Sy mingw64/mingw-w64-x86_64-icustack build text-icu

I managed it by doing:

• Download the binaries from http://site.icu-project.org/download/56#TOC-ICU4C-Download, specifically http://download.icu-project.org/files/icu4c/56.1/icu4c-56_1-Win32-msvc10.zip.
• Extract the contents of icu/bin into the directory C:\bin which is on my %PATH%. Extract the contents of icu into the directory C:\bin\icu.
• Use Stack to run stack ghci text-icu --extra-lib-dirs=c:\bin --extra-include-dirs=c:\bin\icu\include.
• In GHCi, run import Data.Text.ICU.Normalize, then :set -XOverloadedStrings, then normalize None "test".
• For each dll that is reported as cannot be found, e.g. icuuc.dll, take the C:\bin\icuuc56.dll and make a copy at C:\bin\icuuc.dll. For me, there were three relevant dlls.

After all that, I can normalise a string in ghci.

This is how windows reacts to a missing static dependency. When the operating system starts a process it looks for static dependencies. If one is missing, then program is not started.

Use depends.exe to find out what import is missing. That could be a missing dll or one that is the wrong version.

Depends is available with 1. Visual Studio 2. The Microsoft Platform SDK 3. Other microsoft packages 4. http://www.dependencywalker.com

It pretty indispensable when tracking down what is happening in this case.