Project 1: The IDLE Development Environment

Due date: Tuesday, April 8, 2025

Foreword

One of primary objectives of this course is for students to develop the ability to read documentations effectively. Therefore, in guiding you through the setup of your development environment for IDLE, we will not in this document be providing detailed step-by-step instructions, as you may customarily have found in previous classes. File paths and commands may be slightly off and need to be edited, and/or there may be commands you need to run that are not listed in the writeup. We hope that you will be able to use documentation and other resources allowed by this course to fill in the gaps!

Submitting Your Project (Read This First!)

In addition to viewing this developer’s guide on our web page, you should also have received a version of this guide as a Markdown file, which you will be editing and submitting for credit.

Once you accept the GitHub assignment (described in a later section), please create a file called SETUP.md in the Lib/idlelib sub-directory of the repository. Here’s what to do with it for this project–

You will create three headers in this file.

  1. Process: In this section, you should list out the steps that you took to complete this project, such as the commands you followed, things you had to look up, etc. As you work through this guide, please add details and descriptions that you think will help future developers follow the setup process to the markdown file. You should also include several screenshots for each step as you do it on your machine. Think of this document to be a guide for future developers to also set up their development environment. They should be able to refer to this section to see how you built the source code.

  2. Bugs Encountered: Record any unexpected issues that you dealt with while following the guide so that future developers know how to handle them if they encounter the same issues. If you did not encounter any issue/bugs, please describe the relevant details of your process/machine for replication.

  3. What I Learned: At the start of this project, you likely do not understand all there is to know about setting up the code base for development. So you should reflect on what new things you learned as you set up your environment, and record them in this document.

Once you complete this project, your completed development environment setup is what you will continue to use for the upcoming individual projects. So make sure you get started early!

How To Submit

DO NOT add SETUP.md directly in your main branch! Instead, create a separate git branch, create SETUP.md in this branch, and create a pull request for that branch in your own repository. We will be reviewing your pull request for grading.

Project Summary

The source code for IDLE is located within the official CPython repository, which is the reference implementation of the Python programming language. Since we would like to avoid working directly on our operating system’s installation of Python1, we will create our own working copy of Python as the foundation of our development environment.

This guide was created with the author’s experience from creating a development environment on the following setup:

  • Ubuntu 22.04 LTS
  • gcc 11.3.0
  • Visual Studio Code
  • git 2.34.1

For the most part, we will be referring to Python’s own Developer’s Guide. We will highlight several most relevant sections of the official documentation, as well as the order in which you should follow them. This document assumes reasonable familiarity with Python, git, and the command line interface in a UNIX-bassed environment such as Linux or MacOS.

IMPORTANT:

If you have a Windows machine, it is highly recommended that you install Windows Subsystem for Linux (WSL 2) so you can work in a UNIX- based environment. The staff members can only provide very limited support for students working in a native Windows environment.

Downloading the Codebase

The first step is to download the source code for CPython onto your machine for local development.

Here, instead of following the official Python developer’s guide, we have created our own master copy of the CPython code base, which we will distribute through GitHub Classroom.

Accept the GitHub Classroom Assignment here: GitHub Classroom Invitation

Once you accept the GitHub Classroom assignment, you should have your own repository containing the CPython source code.

You will then need to use git to clone the repository to your own machine.

If you do not have git installed: follow this guide.

Note: Do NOT follow the “Get the source code” section of the official Python Developer’s Guide! Use our own GitHub Classroom repository instead.

Building Your Own Python

Before compiling our Python interpreter from the source code, we will need to install some additional OS dependencies for certain modules to work properly. The most important one we need is the tkinter package2. To install them on your system, follow this section of the official guide:

Now that the necessary dependencies have been installed, we can go ahead and build our working copy of Python. Follow this section of the official guide:

Fow now, you can stick to the default configuration flags recommended by the guide.

Note that since we have already installed all the ncessary dependencies, you should not see the list of extension modules that have not been built as mentioned in the guide. Instead, you should see something like:

Note: Deepfreeze may have added some global objects,
      so run 'make regen-global-objects' if necessary.
Checked 111 modules (30 built-in, 80 shared, 1 n/a on linux-x86_64, 0 disabled, 0 missing,
0 failed on import)

Once you have the “working build” as mentioned int he documentation, you should run it to check that you have indeed successfully built Python with the extension modules. For example, to check for the tkinter module, run the compiled Python interpreter in the terminal, and try–

$ ./python
Python 3.14.0a6+ (heads/main:2cdc518, ...) [GCC 11.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import tkinter
>>>

If all went well, you should be able to successfully import the tkinter module without any exceptions thrown.

Running IDLE

Once all that is set up, you can now run IDLE with your own Python that is separate from the OS version. Navigate to the CPython repository where your python executable is, and start IDLE from the terminal like so:

$ cd ~/CPython  # go to the CPython repo
$ ./python -m idlelib

You should now see the IDLE program starting as it normally would.

Setting Up Your Editor

You can use whichever editor you prefer, but if you do not personally have a strong preference, we would highly recommend you to follow this guide to set up Visual Studio Code as your primary editor.

Note: If you choose not to follow this guide for VSCode, you should still figure out how to select the correct Python interpreter for the language server in your editor to work properly.

Warning: For submission, if you choose not to use VSCode, please document your process for setting up your choice of editor in SETUP.md!

Visual Studio Code (VSCode) has in recent years become one of the most popular code editors in the industry.

One of the many reasons for its enormous popularity is its extensive support for a wide range of programming languages through extensions. For Python development, the Python extension, and almost a necessity for working with large code bases3.

Once you have VSCode and the Python extension installed on your machine, you can navigate to the directory where you cloned the CPython repository, and open the directory containing the source code for IDLE: CPython/Lib/idlelib.

The first thing you should do is setting the Python interpreter for your workspace. You should set the Python executable you just compiled in the CPython repository as the interpreter. (Use the “Enter interpreter path…” option here, since our own copy of Python likely won’t show up as one of the defaults, which include your system’s global Python installations.)

Once the interpreter is set, you should see the change reflected in the status bar at the bottom of the VSCode window. The Python version displayed there should be the same as if you ran ./python --version with your own Python executable in the CPython directory, something like:

$ ./python --version
Python 3.14.0

  1. Python is an interpreted language, and many different versions of the Python interpreter may exist simultaneously in one system. Your operating system, particularly MacOS or Linux, likely comes with both a Python 2 and Python 3 interpreter installed. ↩

  2. The tkinter package (“Tk interface”) is the standard Python interface to the Tcl/Tk GUI toolkit. Both Tk and tkinter are available on most Unix platforms, including macOS, as well as on Windows systems. ↩

  3. Hey, that’s the name of this class! ↩