Hi
In the meantime, how about the following:
In default non-verbose mode, silently memoize the list of packages that were not found. Then, only if something goes wrong, say something like:
"The package failed to build. Perhaps the reason is that one of the following packages was not found:"
That doesn't seem that helpful. On error, give a list of maybe 25 things that are missing, only to find out that you're running GHC 6.4.1 on Windows which no one ever tried before. It's not really narrowing the cause of the error too much anyway. Something like scons does this much much better than Cabal does - it only complains if it finds something you need but don't have. For example, with Yhc you can compile the compiler with GHC, and the runtime with GCC/Visual Studio. Lacking half those dependancies won't give you an error message if you only try to do the right thing. Thanks Neil