ALT The GHC build system includes all of the above. To illustrate the consequences, here is one rule from GHC’s current build system, which uses Make: $1/$2/build/%.$$($3_osuf) : \ $1/$4/%.hs $$(LAX_DEPS_FOLLOW) \ $$$$($1_$2_HC_DEP) $$($1_$2_PKGDATA_DEP) $$(call cmd,$1_$2_HC) $$($1_$2_$3_ALL_HC_OPTS) \ -c $$< -o $$@ \ $$(if $$(findstring YES,$$($1_$2_DYNAMIC_TOO)), \ -dyno $$(addsuffix .$$(dyn_osuf),$$(basename $$@)) ) $$(call ohi-sanity-check,$1,$2,$3,$1/$2/build/$$∗) Yes, there are four dollar signs in a row! If it wasn’t so tragic, im- penetrable code like this would be hilarious. This kind of thing goes on for thousands of lines. The result is a nighmare to understand, maintain and modify.