TAB key not working in python auto-complete

Question

I'm trying to create an interactive command line program using readline in python.

The file run.py contains the following code:

import readline

class SimpleCompleter(object):
    
    def __init__(self, options):
        self.options = sorted(options)
        return

    def complete(self, text, state):
        response = None
        if state == 0:
            # This is the first time for this text, so build a match list.
            if text:
                self.matches = [s for s in self.options if s and s.startswith(text)]
            else:
                self.matches = self.options[:]
                
        try:
            response = self.matches[state]
        except IndexError:
            response = None
        
        return response

def input_loop():
    line = ''
    while line != 'stop':
        line = input('Prompt ("stop" to quit): ')
        print(f'Dispatch {line}')

# Register our completer function
completer = SimpleCompleter(['start', 'stop', 'list', 'print'])
readline.set_completer(completer.complete)

# Use the tab key for completion
readline.parse_and_bind('tab: complete')

# Prompt the user for text
input_loop()

The problem is when I try to run the file directly from the terminal (ie python run.py ) the TAB key is not considered as auto-completion key, instead it is considered 4 spaces, so I got no suggestions when I press the TAB key twice; However, if I imported the file from a python console (ie import run.py ) the TAB key is considered auto-completion key and I got suggestions as expected.

It seems that the problem is in the line

readline.parse_and_bind('tab: complete')

so I tried to put it in a seperate config file as mentioned here but the problem remained the same.

So the question is why is this happening? and how can I fix it.

Answer 1

Finally found the answer, and the problem was that I am using Mac, so instead of

readline.parse_and_bind('tab: complete')

I have to use

readline.parse_and_bind('bind ^I rl_complete')

Now running the code directly using python run.py , I get the suggestions as expected.