Parsing commands CLI program Python

Question

I used to write my (simple) Python programs in Python 2, but it seems that Python 3 is quite mature. I now have a CLI program called ratjuice.py and when I execute it the program asks for a command input (which I have made some tab completion thing for).

So I might have commands like html which could output the subcommands like parse or destroy. I might want to use the command html parse rat.html. So I am looking for a Python module which allows me to parse this input based on a white list. So I would basically tell what is allowed and the rest is ignored or rejected (I might forget some things if I sanitize the input...)

Is there any good way to do this other than mere string manipulation?

mgilson · Accepted Answer · 2012-08-15 18:43:34Z

1

Have a look at the cmd module. It does line-editing and remembers history (supposedly).

answered Aug 15, 2012 at 18:43

mgilson

312k70 gold badges656 silver badges722 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Izkata · Accepted Answer · 2012-08-15 18:45:30Z

A string parsing version I just slapped together that requires no additional libraries, that works with your "whitelist" idea:

def foo1(bar):
   print '1. ' + bar

def foo2(bar):
   print '2. ' + bar

def foo3(bar):
   print '3. ' + bar

cmds = {
   'html': {
      'parse': foo1,
      'dump': foo2,
      'read': {
         'file': foo3,
      }
   }
}

def argparse(cmd):
   cmd = cmd.strip()
   cmdsLevel = cmds
   while True:
      candidate = [key for key in cmdsLevel.keys() if cmd.startswith(key)]
      if not candidate:
         print "Failure"
         break

      cmdsLevel = cmdsLevel[candidate[0]]
      cmd = cmd[len(candidate[0]):].strip()

      if not isinstance(cmdsLevel, dict):
         cmdsLevel(cmd)
         break


argparse('html parse rat.html')
argparse('foo')
argparse('html read file rat.html')
argparse('html dump rat.html')

Collectives™ on Stack Overflow

Parsing commands CLI program Python

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related