target_sources(core PRIVATE
    "${CMAKE_CURRENT_LIST_DIR}/boolean.cc"
    "${CMAKE_CURRENT_LIST_DIR}/boolean.hh"
    "${CMAKE_CURRENT_LIST_DIR}/ivalue.hh"
    "${CMAKE_CURRENT_LIST_DIR}/number.hh"
    "${CMAKE_CURRENT_LIST_DIR}/string.cc"
    "${CMAKE_CURRENT_LIST_DIR}/string.hh")