RELEASE-NOTES

Copyright ©1996, 1997, 1998 The Regents of the University of
California (Regents). All Rights Reserved. 

Permission to use, copy, modify, and distribute this software and its
documentation for educational, research, and not-for-profit purposes,
without fee and without a signed licensing agreement, is hereby
granted, provided that the above copyright notice, this paragraph and
the following two paragraphs appear in all copies, modifications, and
distributions. 

Contact The Office of Technology Licensing, UC Berkeley, 2150 Shattuck
Avenue, Suite 510, Berkeley, CA 94720-1620, (510) 643-7201, for
commercial licensing opportunities. 

IN NO EVENT SHALL REGENTS BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT,
SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING LOST PROFITS,
ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF
REGENTS HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
  
REGENTS SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE.  THE SOFTWARE AND ACCOMPANYING DOCUMENTATION, IF
ANY, PROVIDED HEREUNDER IS PROVIDED "AS IS". REGENTS HAS NO OBLIGATION
TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR
MODIFICATIONS. 


------------------------------------------------------------------------------
# RELEASE-NOTES for SHIFT ProjectVersion: 3.2 

1 SHIFT now compiles properly without the GUI.

2 SHIFT now compiles under IRIX 6.2 with 'cc'.

3 The reference manual has been updated to reflect all outstanding
  changes.

4 EXPORT events are now allowed to be of one of two types: OPEN,
  CLOSED.  See the reference manual for a description.

5 External types may be declared to be used in conjunction with the
  foreign function interface of SHIFT.  See the reference manual for a
  description of the syntax and semantics of these types.

6 The SETUP clause has been added to the global namespace.

7 A new built-in function has been added for run-time 'type'
  checking.  The function 'components(T)' evaluates to a set of type T
  containing all the components that are of type T (or inherited from T).
  See the reference manual for further information.

8 Several bug fixes.

------------------------------------------------------------------------------
# RELEASE-NOTES for SHIFT ProjectVersion: 3.1 

1 All outstanding synchronization bugs have been fixed.

2 Inheritance has been overhauled and is now in line with standard 
  Object Oriented Practice.

3 A new tool has been added, ShiftDoc.  Which produces HTML pages
  directly from comments in SHIFT Code.  Documentation is online at
  HTTP://www.path.berkeley.edu/shift/doc/shiftdocs.html


------------------------------------------------------------------------------
# RELEASE-NOTES for SHIFT 2.11

1 NEW OPERATIONS OVER SETS AND ARRAYS HAVE BEEN INTRODUCED

SHIFT now contains a few new operations which will make it easier to
program while also improving the efficiency of the run time.

1.a Adding and Removing elements from a set can now be accomplished
    using the '+:=' and '-:=' operators. E.g. given

	set(number) S := { 1, 3, 44, 90 };

    the action

	S +:= 56;

    will effectively add the number 56 to the set.
    Previously this effect could have only be achieved by reassigning
    the S slot with a new (union) set.

	S := S + {56};

    which is a rather expensive operation.

    Deleting via '-:=' is analogous.


1b The new operators FIND, COUNT and CHOOSE have been introduced,
   based on the set former syntax.  They will facilitate writing
   programs which need to extract given elements from a set or counting
   how many elements in the set satisfy a given property.  E.g. given
   the previous set 'S', the action

	bign := count { o : o in S | n > 10 };

   will store the number 2 into 'bign'.


2 REFERENCE MANUAL

  The reference manual is now automatically included in the
  distribution.


3 FIXES

  Several bugs fixes went into this distribution.  Most of them should
  be totally transparent to the end user.


------------------------------------------------------------------------------
# RELEASE-NOTES for SHIFT $ProjectVersion: 5.59 $

1 DEPENDENCIES on [incr tcl] and [incr tk] ELIMINATED

The SHIFT GUI (TkShift) does not need [incr tcl] and [incr tk]
anymore.  You do not need to install them in your system before
running TkShift.  However, you still need BLT (most likely the
BLT8.0-unoff version if you are running Tcl 8.0).


2 FOREIGN FUNCTION INTERFACE IMPROVED AND EXPANDED.

You can now declare foreign function (C functions) which accept
pointer parameters in order to simulate copy-in/copy-out operations.

E.g. you can now define a C function which analyzes an array of data
points and returns average, median and standard deviation.

	function statistics(array(number) data_points;
                            number data_points_dim;
                            number out average;
                            number out median;
                            number out stddev)
		 -> number;

The C function will have the following signature

	double
	statistics(double data_points[],
		   double data_points_dim,
		   double* average,
		   double* median,
		   double* stddev);


3 SHIFT API RELEASED

SHIFT now comes with a C API that allows you to run and control SHIFT
simulations from C Programs.  Check the WEB pages at

	http://www.path.berkeley.edu/shift

for extended documentation on this feature.


------------------------------------------------------------------------------
# RELEASE-NOTES for SHIFT ProjectVersion: 3.98

1 SET/ARRAY FORMERS AND RANGES

SHIFT now has set/array formers expressions in the spirit of SETL (if
you know anything about this language.) I.e. you can now write
something like

	...

	define
	  {
	    set(number) s := {x * 2 : x in {2, 4, 6}};
	  }

	...

The result is of course to store '{4, 8, 16}' in 's'.

A different example is the following

	define
	  {
	    array(number) N := [i : i in [0 .. 1000]]
	  }

which generates an array containing all the numbers from 0 to 1000
(the '[ x1 .. x2 ]' form is a 'range'.)

Please consult the reference manual for more information about the
array and set formers.


2 SYNTAX.

This version of SHIFT contains two major non-backward compatible
syntax changes.

The first one is in the 'define' clause of setup and transition
actions.

Whereas in previous SHIFT version you could write

	define
	  {
	     x := 4.3;
	     c := create(component, xd := 8.0);
             s := { create(c1), create(c1) };
          }
        do
          {
		...
	  }

Now you must also specify the type of the variable.  I.e. the previous
example will become:

	define
	  {
	     number x    := 4.3;
	     component c := create(component, xd := 8.0);
             set(c1) s   := { create(c1), create(c1) };
          }
        do
          {
		...
	  }

We believe that this will make the language more consistent.  The scope
rules do not change.

The second change concerns the set up of input/output connections and
synchronizations among several components.

In the previous version of SHIFT, the setup clause could contain the
following statements in a 'do' clause

	...
	do
	  {
	    x := 33.0;                        // 1
	    v(something) := 44.8;             // 2
            y(something) = y(something_else); // 3
	    y:alpha <-> whatever:beta;        // 4
            zz := get_this_from(whatever);    // 5
	  }

The intended sequence of executions would delay the set up of the
"connection" between 'y(something)' and 'y(something_else)' (statement
3) and of the synchronization 4, after the execution of actions 1,2,
and 5.

Since the equation notation is in this case used mostly for making I/O
connections, we decided to make such use explicit.  To achieve this
goal we introduced a new bit of syntax in the form of an extra clause
in the setup where all the I/O connections are made using a new (and
hopefully more explicit) syntax.  The above example would be written
as

	...
	do
	  {
	    x := 33.0;                        // 1
	    v(something) := 44.8;             // 2
            zz := get_this_from(whatever);    // 5
	  }
	connect
	  {	  
            y:alpha <-> whatever:beta;         // 3
            y(something) <- y(something_else); // 4
	  }

The scoping rules do not change, but now the order of "execution" is
explicit and visually immediate.  Note also the use of the new
operator '<-' instead of '='.

It goes without saying that all the old SHIFT programs will have to be
rewritten, but we felt that we are early enough in the distribution
process that this would not affect too many people.


3 PORTS AND COMPATIBILITY

The current version of SHIFT (compiler and runtime only) has been
succesfulyy built on the following architectures using the following
tools

	Machine			OS		Tools
	=======================================================
	Sun SPARC 4m,4u		Solaris 2.5.*	GNU C, GNU Make
				SunOS 4.1.*	GNU C, GNU Make
	-------------------------------------------------------
	Intel x86		FreeBSD		GNU C, GNU Make
	-------------------------------------------------------
	SGI			IRIX 5.3(*)	GNU C, GNU Make
						SGI C, GNU Make
	-------------------------------------------------------
	IBM RS6000		AIX 4.1		GNU C, GNU Make
	=======================================================	

(*) IRIX 6.[23] will be tested soon.


4 KNOWN BUGS AND UNIMPLEMENTED FEATURES

a - '<->' still has some problems due to a leftover bug in the
    implementation of the I/O connections

b - Ranges for 'exists' queries are not yet implemented.


The SHIFT Team, 19970131