$ ./miniplc0 -l -
Unknown argument
Usage: miniplc0 [options] input
Positional arguments:
input speicify the file to be compiled.
Optional arguments:
-h --help show this help message and exit
-t perform tokenization for the input file.
-l perform syntactic analysis for the input file.
-o --output specify the output file.[Required]
看来是 argparse 还有些bug,待修。