PROGRAM: lib.opt
ARGUMENT:     "pos1"
LONG_OPTION:  "--val1" with value "for_val1"
LONG_OPTION:  "--val2" with value "for_val2"
ARGUMENT:     "pos2"
LONG_FLAG:    "--flag1"
SHORT_OPTION: "-v4" with value "for_val4"
LONG_FLAG:    "--flag2"