There are dozens (maybe hundreds) of computer programming languages.
Some are written for special purposes (like controlling a telescope or a car engine), some are written to be used by any kind of application. Most computer languages can only be used on a single computer, or one very like the one that is used to write the program. For example, a program designed to run on a Mac won't run on Windows unless the programmers modify it for Windows.
The language we'll learn in these lessons is called Tcl/Tk. Tcl/Tk is a general purpose programming language that allow the same program to be run on computers using Microsoft Windows, Linux, Unix, or MAC OS without any modifications.
This is useful if you want to share your latest nifty game with your friends.
The main program we'll use is called
wish. This stands
WIndowing SHell. It's called a shell because it
wraps around a Tcl/Tk program the way a clam shell wraps around a clam.
Technically, it's called an interpreter, because it interprets
the Tcl/Tk commands and translates them into CPU commands.
The first thing you'll need in order to use Tcl/Tk programming language
wish interpreter that converts Tcl/Tk commands to
the computer's on and off values.
You can download this program from
Click this link, then select the free ActiveTcl distribution link to download the ActiveTcl for your computer. You may need to go through a few more pages to finally find the download page.
If you need help installing a program, or information about your computer, ask a parent or teacher for help.
ActiveTcl and then come back to this page.
Ready to continue?
There are lots of ways to start programming a computer, but the easiest way is to let a program help you.
The earliest computers had a bunch of switches on the front, and you'd program them by setting the switch on or off then clicking a button to store the values in the memory. This got old very quickly.
Just as people have been making better and better computer languages over the years, they've been making better and better tools for the computer programmer to use to write the programs.
ActiveState created a program that will make learning Tcl/Tk easier, and best of all, they give it away for free.
You can download the Komodo Edit program from
Do that now, and install it on your computer.
This installs the computer programs that understand the Tcl/Tk language and convert those commands into data values the computer can understand.
In the next lesson we'll see how to run Komodo Edit and write our first simple game.