
------------------------------------------------------------------------
                      [incr Tcl] - version 1.5
------------------------------------------------------------------------
  This version will only work with Tcl version 7.0 and beyond.
  At this point, it has only been tested with versions 7.0-7.3.

  Please send comments or suggestions to michael.mclennan@att.com.
========================================================================
              Copyright (c) 1993   AT&T Bell Laboratories
========================================================================
Permission to use, copy, modify, and distribute this software and its
documentation for any purpose and without fee is hereby granted,
provided that the above copyright notice appear in all copies and that
both that the copyright notice and warranty disclaimer appear in
supporting documentation, and that the names of AT&T Bell Laboratories
any of their entities not be used in advertising or publicity
pertaining to distribution of the software without specific, written
prior permission.

AT&T disclaims all warranties with regard to this software, including
all implied warranties of merchantability and fitness.  In no event
shall AT&T be liable for any special, indirect or consequential
damages or any damages whatsoever resulting from loss of use, data or
profits, whether in an action of contract, negligence or other
tortuous action, arising out of or in connection with the use or
performance of this software.
========================================================================


Implementation Notes:

[incr Tcl] adds object-oriented programming facilities to Tcl.  It
was NOT designed as yet another whiz-bang object-oriented programming
language; indeed, it is patterned somewhat after C++.  It was designed
to support more structured programming in Tcl.  Scripts that grow
beyond a few thousand lines become extremely difficult to maintain.
[incr Tcl] attacks this problem in the same way that any object-
oriented programming language would, by providing mechanisms for
data encapsulation behind well-defined interfaces.  In many cases,
ideas for new widgets or objects can be prototyped using [incr Tcl],
and if necessary, the code can be translated to C for more efficient
execution; the public (Tcl) interface, however, could remain unchanged.


READ THE INTRO:

A tutorial explanation of [incr Tcl] is presented in the PostScipt
file "Intro.ps".  This tutorial describes a family of "Toaster"
classes that illustrate many of the features available in this package.
Source code for the example classes is provided in "demos/toasters".


INSTALLATION AND TESTING:

  1)  Obtain this distribution from harbor.ecn.purdue.edu:

        ftp harbor.ecn.purdue.edu
        cd pub/tcl/extensions
        binary
        get itcl-1.5.tar.gz
        quit

  2)  Uncompress and untar the distribution:

        uncompress itcl-1.5.tar.Z
        tar xvf itcl-1.5.tar

  3)  Run the configuration script:

        cd itcl-1.5
        ./configure

      or, for systems that don't recognize "#!" in shell scripts:

        cd itcl-1.5
        /bin/sh ./configure

      By default, the configuration script will set things up
      to be installed in "/usr/local".  You can change this by
      specifying a different "prefix" in the "configure" command:

        ./configure --prefix=/your/install/path

      You may be queried for the location of Tcl/Tk include files
      and libraries.  Note that this package also requires the
      path to the Tcl source code, since it requires "tclInt.h"
      and this file is not usually installed with the standard
      include files.

      The "configure" script generates new Makefiles from their
      respective templates (Makefile.in).

      If "configure" can't find something, you can make changes
      to the intermediate "config.status" script, and invoke this
      script to reconfigure the Makefiles:

        vi config.status
        ./config.status

      As a last resort, you can edit the Makefiles in "src/",
      "man/" and "library/" by hand and insert the proper paths.

  4)  Build the libraries and the executables:

        make all

  5)  Test by running the demos:

        cd demos
        ../src/itcl_wish -f coloredit
        ../src/itcl_wish -f listboxes

  6)  Install the libraries (libitcl.a and libitcl.so.1.5) and the
      executables (itcl_sh and itcl_wish), along with the man page
      and library scripts onto your system:

        make install


ADDING [incr Tcl] TO YOUR OWN APPLICATION:

  To add [incr Tcl] facilities to a Tcl application, modify the
  Tcl_AppInit() routine as follows:

  1) Include the "itcl.h" header file near the top of the file
     containing Tcl_AppInit():

       #include "itcl.h"

  2) Within the body of Tcl_AppInit(), add the following lines:

       if (Itcl_Init(interp) == TCL_ERROR) {
           return TCL_ERROR;
       }

  3) Link your application with libitcl.a

  NOTE:  Example files "tclAppInit.c" and "tkAppInit.c" containing
         the changes shown above above are included in this
         distribution.


DEMO CLASSES:

Example classes in the "demos/widgets" directory illustrate how
[incr Tcl] can be used to create new widgets that look (from a
programming standpoint) like normal widgets but are written entirely
in Tcl.  These widgets are defined as object classes, and pack
primitive widgets together to provide higher-level functionality.

Two demos are provided which illustrate how these "mega-widgets"
could be used in a real application:

    demos/listboxes .... Illustrates high-level listboxes:
                           - ListBox
                           - SelectBox
                           - FilteredBox

    demos/coloredit .... Allows colors to be changed in another
                         Tk application.  Illustrates:
                           - FilteredBox
                           - ColorEditor

Once you have created and installed the "itcl_wish" application which
recognizes [incr Tcl] facilities, you can invoke these demos as:

	% cd demos
    % itcl_wish -f listboxes
    % itcl_wish -f coloredit

It is necessary to sit in the "demos" directory when running these
scripts, since they need to access the class definition files that
reside in the "widgets" directory below.


LIBRARY ROUTINES:

The "library" directory contains a few useful Tcl procedures:

    library/itcl_mkindex.tcl .... the usual "auto_mkindex" proc
                                  updated to include [incr Tcl]
                                  classes when building an index

    library/itcl_reload.tcl ..... a series of procedures for
                                  unloading and reloading class
                                  definitions; useful when debugging
                                  [incr Tcl] applications.


SUMMARY:

Widgets provide a natural domain for object-oriented programming
techniques.  They are not, however, the only domain.  I believe that
[incr Tcl] can be used in more diverse applications to add structure
to Tcl programs.  The "itcl_class" mechanism should be used to group
related procedures and their shared data into a neat little package
with a well-defined interface.

Please experiment with this facility and send me your comments.

--Michael

    =--===   ///////////////////////////////////////////////////////////
  =-----====   Michael J. McLennan 2C-226    michael.mclennan@att.com 
 =------=====  AT&T Bell Laboratories
 ==----======  1247 S Cedar Crest Blvd        Phone: (610) 712-2842
  ==========   Allentown, PA  18103             FAX: (610) 712-3843
    ======   ///////////////////////////////////////////////////////////
