Hi Ashley, Unfortunately Yhc is not that well maintained or usable - the GHC compiler is a lot more robust. If you want to work through something like YAHT with two compilers, I'd recommend Hugs and GHC.
darcs get --partial --repo-name=depends/cpphs http://www.cs.york.ac.uk/fp/yhc/dependencies/cpphs
darcs failed: Failed to download URL http://www.cs.york.ac.uk/fp/yhc/dependencies/cpphs/_darcs/patches/2005122014...:
Weird. I will check this one out - sounds very suspicious.
scons: *** Source `depends/ctypes/libffi/src/x86/ffi_darwin.c' not found, needed by target `depends/ctypes/libffi/src/x86/ffi_darwin.o'. Stop. scons: building terminated because of errors.
It looks like you are building on Mac, which I know people have had difficulty with in the past. I'm not sure if anyone has figured it out yet? Thanks Neil