People pronounce Tcl as "Tickel". Tcl means Tool Command
Language. Usually, you see Tcl paired with its young brother, Tk. Tk is the Tcl toolkit for building graphical user interfaces.I was first introduced by this cool Tcl language about 3 years ago when I tried to find a solution to automate the
compilation of Quartus II overnight and during the weekend. Basically, I had about twenty
different Quartus II projects to compile and each of them took a few hours to complete due to the large logic usage and strict timing requirement inside the designs. If I didn't automate this process, I would be wasting my time to do the manual push-button compilation after every one or two hours of compilation, which was kind of stupid. So, that was my first purpose of using the Tcl language.However, soon after that, I found out that the Tcl language is not merely a scripting language that is limited for automation process. It can do much more than that, such as file processing, easy interface with the PC serial port without any external DLL, easy construction of GUI, interface with a DLL
written by you or others, etc. Besides that, I also found out that most of the FPGA tools like Quartus II, ISE and famous third-party simulation tool, ModelSim, provide the API and platform for you to command them in Tcl language.One of the reasons people use Tcl language is that the script written in Tcl language works regardless of the operating system
used. It saves the hassle of providing the
software in different versions just to support different OS.If you never heard about the Tcl and are interested with this Tcl language, you can go to ActiveState (www.activestate.com) to download the ActiveTcl software, and it is freely distributed. There are many Tcl application examples that you can easily download from the website for reference. If you would like to know even more details about this cool language, you can read the Practical Programming in Tcl and Tk written by Brent B. Welch, Ken Jones with Jeffrey Hobbs. This Tcl/Tk bestseller comes with a CD-ROM that includes all the examples used in the book and also the ActiveTcl software which may have been outdated. This book (fourth edition) has been my Tcl/Tk bible since I start using Tcl and Tk and it still is.