rule("cppfront")
    set_extensions(".cpp2")
    add_orders("cppfront", "c++.build")
    on_build_file(function (target, sourcefile, opt)
        print("build cppfront file")
        local objectfile = target:objectfile(sourcefile:gsub("cpp2", "cpp"))
        assert(not os.isfile(objectfile), "invalid rule order!")
    end)

target("test")
    set_kind("binary")
    add_rules("cppfront")
    add_files("src/*.cpp")
    add_files("src/*.cpp2")
    before_build_file(function (target, sourcefile, opt)
        local objectfile = target:objectfile(sourcefile)
        os.tryrm(objectfile)
    end)