------------------------------------------------------------------------
                      [incr Tcl] - version 2.0
------------------------------------------------------------------------
  This version includes tcl7.4p3 / tk4.0p3 upgraded to support
  namespaces, along with [incr Tk] and [incr Widgets].

  Please send comments or suggestions to michael.mclennan@att.com.
========================================================================
           Copyright (c) 1993-1995   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.
========================================================================

 OVERVIEW
------------------------------------------------------------------------
 - What is [incr Tcl]?
 - Getting started
 - Installation
 - Integrating [incr Tcl] with other extensions
 - Acknowledgements
------------------------------------------------------------------------


 What is [incr Tcl]?
------------------------------------------------------------------------
 [incr Tcl] started as a small, object-oriented extension of the
 Tcl language.  It was originally conceived to support more structured
 programming in Tcl.  Tcl scripts that grow beyond a few thousand lines
 become extremely difficult to maintain.  This is because the building
 blocks of vanilla Tcl are procedures and global variables, and all of
 these building blocks must reside in a single global namespace.  There
 is no support for protection or encapsulation.

 [incr Tcl] introduces the notion of objects.  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.

 Among other things, [incr Tcl] can be used to create new widgets that
 look and work like the usual Tk widgets, but are written entirely at
 the Tcl language level (C code is optional).  These "mega-widgets"
 can be created using [incr Tk], a set of base classes which provide
 the core mega-widget functionality.  [incr Widgets] is a set of
 high-level mega-widgets built using [incr Tk].  It has more than
 30 widget classes, and can be used right out of the box to create:

   - fileselectiondialog
   - tabnotebook
   - panedwindow
   - combobox
   - optionmenu
   - scrolledlistbox
   - scrolledframe
   - messagedialog
   - and many others...
 
 Classes and/or related procedures can also be encapsulated in their
 own "namespace".  A namespace is a collection of commands, variables,
 classes and other namespaces that is set apart from the usual global
 scope.  Elements within a namespace can be "private" or "protected",
 so that access to them is restricted.  An "import" command allows all
 of the elements from one namespace to be integrated into another.

 Extension writers will immediately see the benefit of namespaces.
 With vanilla Tcl, each extension must add its commands and variables
 at the global scope.  Extension writers are encouraged to add a unique
 prefix to all of the names in their package, to avoid naming collisions.
 Extensions can now sit in their own namespace of commands and variables,
 and sensitive elements can be protected from accidental access.  For
 example, the current release of [incr Tcl] has a namespace "::itcl"
 for object-oriented support, a namespace "::itk" for mega-widget
 support, and a namespace "::iwidgets" for the [incr Widgets] package.
 Each of these namespaces has its own collection of commands and
 variables.  Developers can then pick and choose among the extensions,
 and integrate the parts that they need for their application by
 importing various namespaces at the global scope.


 Getting started
------------------------------------------------------------------------
 Read the first part of the CHANGES file for a brief overview of
 new commands, and a summary of important changes.  Consult the
 man pages for detailed information on particular commands.

 Check out our web site on WebNet for extra doc and the latest
 news:

     http://www.wn.com/biz/itcl/

 Build and install the package as described below, then check
 out the "catalog" demo in the "iwidgets2.0.0/demos" directory.
 This shows off all of the mega-widgets available in the
 [incr Widgets] package.  The file "iwidgets2.0.0/doc/iwidgets.ps"
 contains a tutorial introduction to the [incr Widgets] package.

 The mega-widget classes in the "iwidgets2.0.0" directory show off
 most of the functionality in this release.  They are excellent
 code examples for creating new widget classes.


 Installation
------------------------------------------------------------------------
  1)  Obtain this distribution from an archive site like this:

        ftp ftp.aud.alcatel.com
        cd pub/tcl/extensions
        binary
        get itcl2.0.tar.gz
        quit

  2)  Uncompress and untar the distribution:

        gunzip itcl2.0.tar.gz
        tar xvf itcl2.0.tar

  3)  Run the configuration script:

        cd itcl2.0
        ./configure

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

        cd itcl2.0
        /bin/sh ./configure

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

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

      You can also add options for a particular "cc" compiler and
      compiler flags:

        ./configure --with-cc=gcc --with-cflags=-g

      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.  From the toplevel
      directory type:

        make all

  5)  Install the libraries, executables, man pages and script files.
      From the toplevel directory type:

        make install

  6)  [incr Tcl] and [incr Tk] can also be built and installed as
      shared libraries on some systems.  If you want to do this,
      you must do an extra step:
      
        cd itcl
        make shared
        cd ../itk
        make shared


 Integrating [incr Tcl] with other extensions
------------------------------------------------------------------------
 [incr Tcl] now requires its own version of Tcl/Tk with support for
 namespaces.  Therefore, you must use the version of Tcl/Tk that
 comes in this distribution as a basis for other applications.
 Hopefully, the namespace support will become a part of the standard
 distribution some day.

 You can add other extensions into the [incr Tcl] package by
 following the usual instructions for Tcl/Tk:

  1) Put the source code for the extension in the directory
     "itcl2.0", at the same level as the directories "tcl7.4"
     and "tk4.0".  You must compile the extension with the
     include files and libraries for the version of Tcl/Tk
     included in this release.

  2) Copy "tclAppInit.c" or "tkAppInit.c" from the standard
     distribution.  Choose the appropriate version according to
     your needs:

       tcl7.4/tclAppInit.c .... Tcl with namespaces
       tk4.0/tkAppInit.c ...... Tcl/Tk with namespaces
       itcl/tclAppInit.c ...... Tcl with namespaces and [incr Tcl]
       itk/tkAppInit.c ........ Tcl/Tk with namespaces and [incr Tcl]/[incr Tk]

  3) Each extension should have an initialization function with a
     name like "XXX_Init()".  The BLT package, for example, has a
     function "Blt_Init()".

     a) Include the declarations for any initialization routines
        at the top of the tclAppInit.c or tkAppInit.c file.

     b) Within the body of Tcl_AppInit(), add a call to the
        initialization routine.  It should look something like this:

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

        In this example we have integrated BLT in with [incr Tcl] and
        [incr Tk].

  4) Link your application with the appropriate libraries:

       libtcl.a ............ Tcl with namespaces
       libtk.a ............. Tk with namespaces
       libitcl.a ........... [incr Tcl]
       libitk.a ............ [incr Tk]
       -lX11 ............... X11 library


 Acknowledgements
------------------------------------------------------------------------
 Thanks to George Howlett for teaching me how namespaces should really
 work.  He has been a constant source of inspiration, and has kept
 a careful watch against many bad ideas.  Jim Ingham fleshed out the
 notion of explicit scoping, and added many nice features to [incr Tk].
 Bill Scott, with a steady stream of bug reports, helped me understand
 the questions that a typical user might have.  He forced me to reinvent
 the paradigm on more than one occasion.

 Thanks to Mark Ulferts, Bill Scott, Bret Schuhmacher, Sue Yockey,
 Alfredo Jahn, John Sigler and other cohorts at DSC Communications Corp.
 With a sketchy overview and a crappy prototype of [incr Tk], they
 managed to build a nice set of mega-widgets.  Their initial designs
 helped me smooth out the rough spots in [incr Tk].

 Thanks to more than 100 beta-testers that helped me polish this release.

 Thanks to Alfredo Jahn and Bret Schuhmacher at WebNet for helping
 to create the [incr Tcl] web site.

 Thanks to Mark Harrison for his enthusiasm and support.  Due in
 large part to his evangelism, I have been able to make [incr Tcl]
 development a mainstream activity.

 And many thanks to my wife Maria and my son Maxwell for putting up
 with all of this.

--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) 712-2773
    ======   ///////////////////////////////////////////////////////////
