Short form of incr Tcl, iTcl is simply a set of object-oriented extensions meant for the Tcl programming language. These extensions are extensively used by all the TCL enthusiasts throughout the world. Generally referred to as the ‘industrial strength’, its name is actually a pun on the C++ language! The iTcl implementations exist both in the form of a standalone independent language (having its own interpreter) as well as a package which can be dynamically loaded by any Tcl application.

Applications created with Tcl Tk have the ability of coming together with great ease. You can create a simple video game in as less as 3-4 hours! A sticky note application can be finished in less than an hour! However, with the applications getting bigger, it’s obvious for their Tcl Tk codes to also become increasingly difficult to comprehend, maintain and extend.

This is where incr Tcl comes into the picture. It provides an extra level of language support, necessary for creation of large Tcl Tk applications. iTcl introduces something known as objects, which function as the different building blocks of applications. Every object is a data bag consisting of a unique set of methods or procedures, which are used for its manipulation. These objects are further organized into different classes, having identical characteristics. These classes are allowed to inherit their functionality from each other. Such object-oriented paradigm results in addition of another organization level, on top of the basic procedural or variable elements. The final resultant code is much easier to comprehend and maintain.

iTcl facilitates usage of namespaces for better organization of variables and commands. Just like Tcl, iTcl also has built-in support for easy integration of the C based codes into the iTcl classes.

The last known release of iTcl provides enhanced performance as well as a host of different features such as:
– The [incr Tk] framework for the creation of mega widgets.
– The mega-widget set [incr Widgets].
– Namespaces for better organization of variables and commands.
– Comprehensive support for easy integration of C++ or C code into the [incr Tcl] classes.

Ever since its introduction in the year 1993, iTcl or incr Tcl has gone on to gain huge popularity among the Tcl Tk enthusiasts, and their development community. Furthermore, the list of applications depending on the incr Tcl is also growing day by day.