[incr Tcl] is an object system for the Tcl programming language.

[incr Tcl] provides the extra language support needed to build large Tcl/Tk
applications. It introduces the notion of objects, which act as building
blocks for an application. Each object is a bag of data with a set of
procedures or "methods" that are used to manipulate it. Objects are
organized into "classes" with identical characteristics, and classes can
inherit functionality from one another. This object-oriented paradigm adds
another level of organization on top of the basic variable/procedure
elements, and the resulting code is easier to understand and maintain.

It should follow without mentioning that this package depends upon the Tcl
packages from your Slackware 13.1 distribution disk being installed.

As well, [incr Tcl], as part of its build process, looks into the Tcl
sources for some header files.  This means that in order to compile [incr
Tcl] that the Slackware Tcl source package needs to be present.  You can
either download the Slackware Tcl source package from a slackware mirror
using the provided link or copy the tcl8.5.8-src.tar.xz file from your
Slackware install disk.  The tcl8.5.8-src.tar.xz source file should be in
the same directory as the itcl.Slackbuild script, and the Slackbuild script
will unpack the tcl8.5.8-src.tar.xz source file automatically as part of the
[incr Tcl] build process.  Once [incr Tcl] is built and installed, the Tcl