rule cxx
  command = g++ -c -o $out $in
  description = CXX $out

rule link
  command = g++ -o $out $in
  description = LINK $out

build build/package.o: cxx src/package.cpp | src/package.h
build build/command.o: cxx src/command.cpp | src/command.h build/package.o

build build/main.o: cxx src/main.cpp

build build/slackbuilder: link build/main.o build/command.o build/package.o

default build/slackbuilder