Tup is really great. I wish it were more widely used. Tup can effortlessly handle a lot of situations that Make chokes on or requires deep magic to get right. A good example is the clean handling of automatically generated header files. This is all it takes to integrate protobufs into a Tupfile:

  : foreach *.proto |> !protoc |> %g.pb.cc | %g.pb.h
  : foreach *.pb.cc | *.pb.h |> !cpp |> %g.pb.o

The "|>" is the pipe operator and I've elided the definitions of the "!protoc" and "!cpp" macros (but they're about what you'd expect). Tup detects whenever a .proto file is changed and does the right thing. Getting this to work with Make requires advanced tricks like .PHONY and .PRECIOUS.