expand_shell.py

def expand(value):
    args = []
    escape = False
    end_section = None
    section = ''
    for c in value:
        # previous character was \, just append this one
        if escape:
            section += c
            escape = False
            continue
        # character is \, signal to escape the next character
        if c == '\\':
            escape = True
            continue
        # we are inside quotes
        if end_section:
            if c == end_section:
                # found closing quote, signal that we are no longer inside quotes
                end_section = None
                continue
        # we are outside quotes
        else:
            # found space, append the section to the arguments
            if c == ' ' and section:  # only append if the current action has something
                args.append(section)
                section = ''
                continue
            # found starting quote, signal that we are now inside quotes
            elif c in ('"', "'"):
                end_section = c
                continue
        # just add the current character to the section
        section += c
    # the text has ended, if we have any data in the section append it to the arguments
    if section:
        args.append(section)
    return args