Download source files: BNFC_2.2.tgz
.
extract the files with: tar -xvfz BNFC_2.2.tgz
or: gunzip BNFC_2.2.tgz ; tar -xvf BNFC_2.2.tar
change directory: cd ./BNFC_2.2/
Make sure that you have the GHC
compiler installed and type: make
You should now have a binary named bnfc.