I just installed the EclipseFP plugin into my Eclipse setup (on Windows 7 32bit, if that matters), following the instructions. Then I followed the directions in the Eclipse help docs to create a Hello World
project successfully.
However, I'm fairly certain something is wrong, though I cannot figure out what. First of all, there's no syntax highlighting, even if I explicitly open files with the Haskell Editor. Secondly, hitting run launches the GHCi console in the Console tab. This is actually fairly useful, but does not sound right, since it doesn't run the file, only compile and load it. Additionally, the Outline view is empty, even when I open a moderately large Haskell file.
Last but not least, the project initially reported there was no Haskell implementation configured. I went into the preferences (though this is not described as being necessary anywhere) and manually added a GHC implementation, pointed to the bin directory of my Haskell Platform installation. As best I can tell, however, this has had no effect.
Best Answer
EclipseFP appears to no longer be actively maintained; use at your own risk.
After a lot of great help from the developers of EclipseFP on their mailing list, I put together a set of instructions for installing the current (2.0.2) version of EclipseFP. You can read my email but below are the instructions - it's long, but not as hard as it looks, and the result is quite nice:
http://eclipsefp.sf.net/updates
into the Work with: field - hit enter. In the box below "Functional Programming" should show up after a few moments, cancel and retry it if it doesn't. Expand "Functional Programming" and check the 2.x.x Haskell Support plugin. Follow the rest of the steps, and EclipseFP will be installed, and will prompt you to restart Eclipse.