CODEWITHSUNDEEP
pythonmoduledependencies
f.rodrigues
f.rodrigues

Reputation: 3587

Multiple Files handling with Codependency - Python

I just finished the tutorial for making a rogue-like-game and I'm on my way to implement freatures.

The problem is, the whole game is a single file with 1k+ lines.

As you can see:

http://roguebasin.roguelikedevelopment.org/index.php?title=Complete_Roguelike_Tutorial,_using_python%2Blibtcod,_part_13_code

I want to divide it in different files/folders to handle the implements better.Maybe a file for each aspect of the game like map/player/npcs/items... but at least divide in Classes/Functions/Main.

The problem is, when I put this in the Main.py:

from Classes import *
from Functions import *

I get 

NameError: name 'libtcod' is not defined

Which is a Module used in Main. Then I tried to import the Main.py in the Classes.py and Functions.py

And get the 

NameError: global name 'MAP_WIDTH' is not defined

MAP_WIDTH is a global variable in Main.py

I also tried to import the whole Main.py in Classes.py and Functions.py

But I get: 

NameError: name 'Fighter' is not defined

Fighter is a Class inside Classes.py

Can anyone help me sort this out so I can start implement freatures.

EDIT: One simple example is:

Main.py

from Functions import *
def plus_one(ab):
    return ab +1

a = 1
b = 2
c = add_things()
print plus_one(c)

Functions.py

from Main import *
def add_things():
    global a,b
    return a + b

It's a simple example, but in the project it get a lot of mutual dependecy between classes/functions and the main file.

Upvotes: 1

Views: 758

Answers (1)

William Denman
William Denman

Reputation: 3154

There are many issues with your code and your planned program architecture. Please read my comment on your post. You need to shore up your knowledge of object oriented programming.

First, it is highly recommended to never use from Classes import *. You should use import Classes. Then to access functions or constants from the module you would use Classes.function_name or Classes.constant. See for more info on how to properly import in Python: http://effbot.org/zone/import-confusion.htm

Second, global variables are not recommended in Python. But if you do need them, you need to remember that in python a global variable means global to a module, not your entire program. Global variables in Python are a strange beast. If you need to read a global variable nothing special is required. However if you want to modify a global variable from within a function, then you must use the global keyword.

Thirdly, what you are doing is called a circle dependancy. Module A, imports Module B and Module B imports Module A. You can define shared functions, classes etc. in a third Module C. Then both A and B can import Module C. You can also defined your constants like MAP_WIDTH in module C and access them from A or B with C.MAP_WIDTH provided you have an import C.

Upvotes: 1

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