Pythonator makes Python coders out of gamers. It runs on a Minetest game server and comes with a companion PyCharm Edu course which teaches gamers how to overcome the obstacles in the game by writing Python programs.

A Pythonator workshop will be held at QSITE conference 2018. Attendees should bring a Windows, Mac or Linux laptop. Android and iPads are not suitable. If you don’t already have the following software installed, please install it prior to attending.

1. Python 3
2. PyCharm Edu v2018.1.2
3. Minetest v0.4.17.1

Also download the courses. Only the first course will be used during the workshop.

1. pythonator_1_easy_minetest_v1.zip
2. pythonator_2_advanced_minetest_v1.zip

Send an email to tim@triptera.com.au to request a free account on the server. Then you can try out the exercises on the server for a few weeks after the completion of the conference.

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Detailed installation – Windows 64 bit

Python 3

From the Python website download Python 3.6.5. Default settings are fine during the install although I recommend users also select “Add Python 3.6 to PATH” which is unticked by default.

PyCharm Edu 2018.1.2

Download and install PyCharm Edu v2018.1.2.
Download the Pythonator companion courses for PyCharm Edu. Do not unzip or extract the companion courses.

• pythonator_1_easy_minetest_v1.zip
• pythonator_2_advanced_minetest_v1.zip

Minetest 0.4.17.1

1. Download Minetest 0.4.17.1.
2. Extract the zip file into your Documents directory so you have a folder Documents\minetest-0.4.17.1-win64.
3. In File Explorer right-click on Documents\minetest-0.4.17.1-win64\bin\minetest.exe and select “Send to > Desktop (Create shortcut)”.

Now you can run Minetest by double-clicking the Minetest icon on your desktop.

 

Detailed installation – Mac

This section is for users of macOS 10.13 who are uncomfortable with using the command line. If you are comfortable using the command line, or running an older version of macOS, see the next section.

Python 3

From the Python website download and install Python 3.6.5. Default settings are fine during the install.

PyCharm Edu 2018.1.2

Download and install PyCharm Edu v2018.1.2.
Download the Pythonator companion courses for PyCharm Edu. Do not unzip or extract the companion courses. Safari users need to ensure Safari doesn’t ‘open “safe” files after downloading’ which automatically unzips these files. This is the bottom setting in the General tab of Safari Preferences…

• pythonator_1_easy_minetest_v1.zip
• pythonator_2_advanced_minetest_v1.zip

Minetest 0.4.17.1

If you are running macOS 10.13 you can download a prebuilt version of minetest 0.4.17.1. To install, open the downloaded dmg file and drag the minetest icon on to the Applications icon. To run the first time right-click the minetest icon in Applications folder and click “Open”. There might be a security warning but you will then be able to click “Open” button.

 

Detailed installation – Mac (using the command line)

This section is for those comfortable with the Mac command line using Terminal application. I prefer installing using Homebrew because it matches the build of minetest to my version of macOS and it is easy to install updates.

Python 3 and Minetest

Type the following in Terminal to install XCode, Homebrew, Python 3 and Minetest if you have not installed them already.

xcode-select --install
/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
brew install python
brew install minetest
open /usr/local/opt/minetest

The last line opens the installed minetest folder in Finder. Double-click the minetest icon. While minetest is running, right-click on the icon in the dock and select “Options > Keep in Dock” to make it easier to run next time.

PyCharm Edu 2018.1.2

Download and install PyCharm Edu v2018.1.2.
Download the Pythonator companion courses for PyCharm Edu. Do not unzip or extract the companion courses.

• pythonator_1_easy_minetest_v1.zip
• pythonator_2_advanced_minetest_v1.zip

Detailed installation – Windows 32 bit

Python 3

From the Python website download Python 3.6.5. Default settings are fine during the install although I recommend users also select “Add Python 3.6 to PATH” which is unticked by default.

PyCharm Edu 2018.1.2

Download and install PyCharm Edu v2018.1.2.
Download the Pythonator companion courses for PyCharm Edu. Do not unzip or extract the companion courses.
pythonator_1_easy_minetest_v1.zip
pythonator_2_advanced_minetest_v1.zip

Minetest 0.4.17.1

1. Download Minetest 0.4.17.1.
2. Extract the zip file into your Documents directory so you have a folder Documents\minetest-0.4.17.1-win32.
3. In File Explorer right-click on Documents\minetest-0.4.17.1-win32\bin\minetest.exe and select “Send to > Desktop (Create shortcut)”.

Now you can run Minetest by double-clicking the Minetest icon on your desktop.

 

Detailed installation – Ubuntu Linux

sudo add-apt-repository ppa:minetestdevs/stable
sudo apt install python3 python3-venv libcanberra-gtk-module minetest 
sudo snap install pycharm-educational --classic
wget https://www.pythonator.com/download/pythonator_1_easy_minetest_v1.zip
wget https://www.pythonator.com/download/pythonator_2_advanced_minetest_v1.zip

To open a course in PyCharm Edu

File menu > Browse Courses > Click the green arrow > Import local course > Select one of the above two files > Click Join

Licence

If you want to run the PyCharm Edu Minetest course developed by Triptera you will need a licence. Licences are free if you are running the course in 2018. Please contact Triptera for a licence. Please provide details where you would like to use the software. The licence covers the “builder_police” mod for Minetest and the “Ninja 2 minetest course” for PyCharm Edu, both of which are available with open source. All other components are covered by free and open source licences. Support is available to assist you setting up the PyCharm Edu Minetest course.

What do students learn

Students doing my PyCharm Edu Minetest course learn the following mathematical concepts

• 3 dimensional coordinate systems
• formulae including uses of integer division and modulo and absolute values

They also learn the following python coding skills

• program flow
• variables
• loops
• conditionals
• data types including ints, strings, lists, tuples, dictionaries, JSON strings
• functions
• modules

Minetest

Minetest is a Minecraft clone allowing players to build block structures in a virtual world. To set up your PyCharm Edu Minetest course server follow instructions at Python programming course using Minetest

Minetest is open source free software which runs on Linux, Mac, Windows plus it even runs on Android, iOS and Haiku. At CoderDojo we used to run this course in Minecraft but have now switched to Minetest because of its many advantages.

• Minetest is free so ninjas don’t have to buy a Minecraft licence.
• Minetest passwords can be set by server op. This is much better than Minecraft which would not ask for the password when ninjas were at home, but as soon as they joined our LAN at CoderDojo Minecraft asked for their password which they couldn’t remember.
• Minetest can run on a LAN with no Internet access. Minecraft users would have to log in to the unreliable library wifi to enter their Minecraft password and then switch networks to our LAN to join the virtual world.
• Minetest is better on low budget hardware. I was running a server on a 2GB RAM Core 2 Duo Linux Mint headless (no monitor) desktop PC.
• Minetest has an excellent modding interface that encourages mods unlike Minecraft which obfuscates its java code to make modding harder. The Lua modding language has surprisingly good performance. I hadn’t used Lua before but I picked it up quite quickly and it is apparently common in other games which need scripting. I did have trouble getting network sockets working in Lua on Windows but eventually solved that problem.

Minetest does not do mobs (monsters and other non player characters) as well as Minecraft. Mobs in Minetest are not native so have to be implemented in mods using the Lua scripting language. This has not been an issue for this course which we run without mobs for better performance.

Op Commands

Running the PyCharm Edu Minetest course is mostly automatic. However there are a few custom commands you can enter through in-game chat to manage the world

/set_player_task player_name task_number
resets a players tasks (replace player_name with player’s name, task_number = 0 to start again)
example /set_player_task tim 1

/set_jail_free_task 1
sets the task a player needs to complete to get out of jail

There are also some useful built-in commands

/help
provides help on chat commands

/help all
lists all the chat commands

/help command
help on a specific chat command. e.g. /help time

/time 6:00
set clock to morning time so players are not in darkness. If this becomes onerous, consider setting the “Time speed” to zero in Settings > Advanced settings > Server / Singleplayer > Game > Time speed

/grant player_name irc_builder
gives a player privileges to use building commands over IRC (should be automatic for new players) will show player’s list of existing privileges.
example /grant tim irc_builder

/revoke player_name irc_builder
opposite of grant

/teleport player_name x y z
move player to new coordinates. e.g. /teleport tim 95 12 20 see help for variations

/setpassword player_name new_password
sets player’s password in Minetest. Password can not be blank or contain spaces if it is to work with ircbuilder.
example /set_password tim sesame

/privs
see what privileges you have

You can even send any of these commands to the server over IRC. Send private messages to the server botnick (eg mtserver). The first message is to login. The second and subsequent messages are the same as the chat commands but replace the / with cmd. Below is an example IRC session. Replace mtuser and mtuserpass with the minetest user and password you want to connect as. The minetest username can be different to the IRC nick name.

login mtuser mtuserpass
cmd privs
cmd time 6:00

You can even use python console to send commands if you don’t have an IRC client. mtuser needs to be the serverop player name

from ircbuilder import MinetestConnection
from coderdojo import ircserver, mtuser, mtuserpass, mtbotnick, channel
mc = MinetestConnection.create(ircserver, mtuser, mtuserpass, mtbotnick, channel)
mc.send_cmd("privs")
mc.send_cmd("time 6:00")

PyCharm Edu is an Integrated Development Environment (IDE) for python which has the additional ability to run courses for learning python programming. It also enables teachers to create those courses. PyCharm Edu is cross platform, running on Linux, Mac and Windows.

At CoderDojo I am mentoring ninjas in coding python so I thought I would try PyCharm Edu. To create a course, I created a series of tasks. Each task is a python program with sections left out to be completed by ninjas (answer placeholders). A task has a task description to explain to the ninjas what to do, and a series of tests to determine when they had completed the task. Each answer placeholder has hints to help solve it, some text which needs to be replaced by the ninja and even the correct answer. The tasks have to provide enough information for the ninja to understand what needed to be done, but not enough that the answer was trivial.

Writing the tests was challenging. The tests needed to check for all possible correct answers. For example, if the correct answer was “x+y” then I should also accept “y+x” or “y + x”. I solved this problem by using the python eval() or exec() to test the value of functions or the effect of statements rather than compare the exact characters typed to the answer.

For example, here is how I used eval() to test for where the correct formula should be (x+y).

def test_formula_1(ninja_answer):
    list_data = [{"x": 5, "y": 15}, {"x": 10, "y": -5}]
    global_data = {}
    correct_answer = "x+y"
    for data in list_data:
        try:
            guess = eval(ninja_answer, global_data, data)
        except NameError:
            failed("NameError: should only be in terms of variables " + ",".join(data.keys()) + " but includes other variables. Your formula: " + ninja_answer)
            return False
        correct = eval(correct_answer, global_data, data)
        if guess != correct:
            failed("Incorrect answer for data " + str(data) + ". Correct answer: " + str(correct) + ". Your answer: " + str(guess) + ". Your formula: " + ninja_answer)
            return False
    return True

The types of tests I used to check for correct answers were

• Exact match – when a string value or number value had to be exact
• Partial match – when only start of string or end of string important
• Formula correct – using eval()
• Statement correct – using exec()
• Printed output correct
• Effect of program – eg results in Minetest world

When the ninja (student) is running the course they have access to a full python IDE, including command completion and debugging. As a teaching aid one of the most useful features is the console where ninjas can test individual python statements. The console has a sub-window showing variables created in the console and their values, great for teaching how variables work.

The ninja can see the code for the current task and a task description describing what they have to do. In the diagram below notice the sections of code with thin rectangles around them. These are the answer placeholders that the ninja needs to replace to solve the task. They shouldn’t need to type outside these rectangles, although they can if they want to embellish the program.

While attempting a task they can do the following actions:

• Get hints on an answer
• Reset the task to undo all their changes
• View the answers (after which they must reset the task)
• Run the program with output going to a local window (ctrl-shift-F10)
• Check the task which assesses how well they have done by running tests
• Advance to next or previous task

Advantages of using PyCharm Edu over web python tutorials or text editors:

• Course can be customised
• Student learns a proper IDE. Useful for developing bigger python projects later
• Python console with variable values display
• Syntax colouring and formatting recommendations
• Command completion
• Logic checking such as:
  • variables declared before used
  • import statements used or missing
  • spelling of function names and variable names
• Python virtual environment support
• Automatic installation of modules listed in requirements.txt either from pypi or LAN
• More reliable and functional than Python IDLE
• Better debugging than Thonny

Problems with PyCharm Edu

I did find some problems with PyCharm Edu. However, Jetbrains have been excellent at responding to my issues in this free software.

• PyCharm Edu is usable but expect occasional hang or lack of responsiveness.
• PyCharm Edu turns off a lot of menu items by default to avoid confusing new students. They can be turned back on in preferences.
• PyCharm Edu and PyCharm Community Edition don’t have the same support for flask or django development found in PyCharm Pro. I was still able to do some flask development.
• Unable to display local images in task descriptions. This feature is apparently coming in an update due in a couple of weeks.
• “Play” button for running tasks mostly didn’t work. However, ctrl-shift-F10 achieved the same functionality reliably.

Conclusion

PyCharm Edu is my choice of tool for teaching python and I am sure most of the problems will be addressed in time.

Do you want to learn at home how to program in python while enjoying the fun of building structures in Minetest? These instructions will help you create your own setup similar to the one used at Coderdojo. First of all, make sure you have finished the instructions for the Minetest client install and the Minetest server install.

The steps to configure your course platform:

1. Install builder_police mod for Minetest.
2. Install courses in PyCharm Edu

To configure your course platform you will need Internet access to download builder_police from github, ircbuilder python module from pypi.org, and the courses from this website.

To run the course you will need Internet access to a public IRC server (e.g., irc.rizon.net) which handles the communications between your python program and Minetest.

Minetest mods

The following commands are to be typed into Git-Bash (Windows) or Terminal (Mac, Linux). Change directory to the minetest mods directory. If the directory doesn’t exist you may have to create it.

cd Documents/minetest-0.5.0-6cfd699b-irc-win64/mods  # Windows 64 bit
cd Library/Application\ Support/minetest/mods # Mac
cd .minetest/mods                             # Linux
git clone https://github.com/timcu/builder_police.git

Now that you have installed the builder_police mod, you need to enable it in Minetest by selecting “configure” for the world, selecting the “builder_police” mod and clicking the “enabled” check box.

Install courses in PyCharm Edu

1. 1. Download the following files without unzipping them. Safari users may have to turn off “Open safe files after downloading” in the “General” tab of the Preferences to stop automatic unzipping.
      • Ninja_1_countdowns_and_number_guessing
      • Ninja_2_minetest_course_v6
   2. Open PyCharm Edu and select “Browse Courses” from the “File” menu.
   3. Underneath the list of courses, click on the small rectangle with an arrow pointing into it and select “Import a local course”.
   4. Select the downloaded file “Ninja_2_minetest_course_v5.zip”.
   5. Once it has imported you can click on the “Join” button in the bottom right hand corner. Joining a course takes a while because PyCharm will set up a virtual environment for your python programming which doesn’t affect other python programs on your computer.
   6. The virtual environment will detect that you need the python module ircbuilder version 0.0.5 or later and give you an option to install or ignore this requirement. Choose “Install requirement”.
   7. To do the course there are some details you need to set so that your python programs can connect to IRC and Minetest. These details are all stored in a file called “coderdojo.py”. In PyCharm, go to the File menu and select “Open…”. Navigate to your home folder, the folder “PyCharmProjects”, then the folder “Ninja 2 minetest course v5”, select “coderdojo.py” and click “OK”.

mtuser = ""      # your minetest username
mtuserpass = ""  # your minetest password. This file is not encrypted so don't use anything you want kept secret. Can't have spaces in it

# The following must match your settings in minetest server > Settings > Advanced Settings > Mods > irc > Basic >
ircserver = ""   # same as IRC server
mtbotnick = ""   # same as Bot nickname
channel = ""     # same as Channel to join

1. 1. You need to fill in the values. Here is an example. Of course, you would need different values for mtuser, mtuserpass and channel.

mtuser = "joe"                   # your minetest username
mtuserpass = "mysecretpassword"  # your minetest password. This file is not encrypted so don't use anything you want kept secret. Can't have spaces in it

# The following must match your settings in minetest server > Settings > Advanced Settings > Mods > irc > Basic >
ircserver = "irc.rizon.net"  # same as IRC server
mtbotnick = "mtserver"       # same as Bot nickname
channel = "##minetest3214"   # same as Channel to join

1. Save this file and you are ready to do the course.

If you want to practice at home building Minetest structures with python programs, you will need to install Minetest server with its mods. Before we start, make sure you have completed the Minetest client install.

The steps to configure the server are:

1. Install git
2. Install mods. irc, irc_commands, irc_builder, signs_lib
3. Configure IRC

Git

Windows users will need to download the latest from https://git-scm.com/ and install. This will also install Git-Bash which is a command line shell similar to those on Mac and Linux.

Linux and Mac users should already have git installed. To test, type the following in the Terminal:

git --version

If it is not installed it will give an error message saying “command not found”. Mac users can download the software from the above site or install it using brew as they did with minetest.

brew install git # Mac

Linux users can install using one of the following if it is not already installed.

apt install git # Ubuntu, Debian

yum install git # Fedora, Centos, Red Hat

Luasocket

The irc mod for minetest requires luasocket. This is difficult to install on windows so I have built a 64 bit version of minetest with irc mod and luasocket already built in. It can be downloaded from minetest-0.5.0-6cfd699b-irc-win64.zip.

On Mac, install luasocket using brew and luarocks.

brew install lua51

luarocks-5.1 install luasocket

On Ubuntu install luasocket using apt and luarocks.

apt install luarocks

luarocks install luasocket

Minetest mods

The following commands are to be typed into Git-Bash (Windows) or Terminal (Mac, Linux). Change directory to the minetest mods directory. If the directory doesn’t exist you may have to create it.

Windows 64 bit

cd Documents/minetest-0.5.0-6cfd699b-irc-win64/mods

Mac

cd Library/Application\ Support/minetest/mods
git clone --recursive https://github.com/minetest-mods/irc.git

Linux

cd .minetest/mods
git clone --recursive https://github.com/minetest-mods/irc.git

Windows / Mac / Linux

git clone https://github.com/ShadowNinja/minetest-irc_commands.git
git clone https://github.com/minetest-mods/signs_lib.git
git clone https://github.com/timcu/irc_builder.git
mv minetest-irc_commands irc_commands

Configure mods and IRC

Every Minetest world in which you want to use these mods needs to have them enabled.

1. Run Minetest.
2. Select [Settings] tab, then [Advanced Settings] button in bottom left
3. Expand: + Server / Singleplayer + Security
4. [Edit] secure.trusted+mods. type in irc
5. Expand: + Mods + irc + Basic
6. [Edit] Bot nickname. For example: mtserver
7. [Edit] IRC server. I like Rizon which has server: irc.rizon.net
8. [Edit] Channel to join. Choose a unique channel . eg ##minetest3214
9. Port number can be 6667 and Auto-connect enabled. Channels starting with ## are generally temporary channels. Remember these settings to use in your python program. Make sure your IRC server allows several connections from the same IP address.
10. From the [Local Game] tab, select your world and click on [Configure]
11. Select mod on the right and click the “enabled” check box above for each of the four
12. Click [Save] button to return to [Local Game] tab
13. Type in a password in green password field and click [Host Game]
14. Users who wish to build structures from python will need privilege irc_builder. After they have logged in grant them this privilege by typing /grant username irc_builder

Program in Python 3

Now you can start to write programs in Python which will build structures in Minetest. Remember to install ircbuilder python module in your python virtual environment so that your program can communicate with IRC and hence with Minetest. You can do this in PyCharm Edu from Settings (Windows) or Preferences (Mac) > Project > Project Interpreter > + (and type in ircbuilder).