Cereal generator

cereal.py

#!/usr/bin/env python
"""
Create successive serials based on a given character list. Optionally, provide a starting point for creating serials.
Use this when you need to generate unique serials for things (where variable length is acceptable).
"""

# Start standard library imports.
from string import ascii_lowercase, digits
from typing import Generator, List
# End standard library imports.


class Cereal:
    def __init__(self, belowCerealObj, charList: List[str], customCharList: List[str] = None) -> None:
        self.belowCerealObj = belowCerealObj
        self.charList = charList
        self.customCharList = customCharList

    def cerealize(self) -> Generator[str, None, None]:
        """
        Create a generator that yields all the characters of belowCerealObj and this instance in successive order.
        """
        if self.customCharList is None:
            self.customCharList = self.charList
        for nowChar in self.customCharList:
            if self.belowCerealObj is not None:
                belowCerealObjCerealizeGen = self.belowCerealObj.cerealize()
                for nowBelowCerealChars in belowCerealObjCerealizeGen:
                    yield nowChar + nowBelowCerealChars
            else:
                yield nowChar
        self.customCharList = None


def cereal_generator(charList: List[str], beforeCerealStr: str = str()) -> Generator[Cereal, None, None]:
    """
    Create a generator that yields successive serials utilizing the Cereal object.
    """
    belowCerealObj = None
    if len(beforeCerealStr) == 0:
        cerealObj = Cereal(belowCerealObj=belowCerealObj, charList=charList)
        cerealObjCerealizeGen = cerealObj.cerealize()
    else:
        for nowIndexInt in reversed(range(len(beforeCerealStr))):
            char = beforeCerealStr[nowIndexInt]
            charIndexInt = charList.index(char)
            customCharList = charList[charIndexInt:]
            cerealObj = Cereal(belowCerealObj=belowCerealObj, charList=charList, customCharList=customCharList)
            belowCerealObj = cerealObj
        try:
            cerealObjCerealizeGen = cerealObj.cerealize()
        except NameError:
            print('"{}" is not a valid serial with the given character lists.'.format(beforeCerealStr))
            quit(1)
        # next(cerealObjCerealizeGen) == beforecerealstr
        next(cerealObjCerealizeGen)
    while True:
        for nowCerealObj in cerealObjCerealizeGen:
            yield nowCerealObj
        belowCerealObj = cerealObj
        cerealObj = Cereal(belowCerealObj=belowCerealObj, charList=charList)
        cerealObjCerealizeGen = cerealObj.cerealize()


def main() -> None:
    """
    The logic of the file.

    The feature of cereal_generator where a valid serial is continued upon is not showcased in executing main().
    """
    cerealGen = cereal_generator(charList=ascii_lowercase + digits)
    for nowCerealStr in cerealGen:
        print(nowCerealStr)


if __name__ == '__main__':
    main()