$Id$
Changes between 3.0 and 4.0:
----------------------------
* Not released yet.
* New in 3.99.4 prerelease (rev 170):
+ Proper plugin support under Win32 and HP-UX.
+ Compilation fixes.
+ Minor bugs fixed.
* New in 3.99.3 prerelease (rev 157):
+ Minor bugs fixed.
* New in 3.99.2 prerelease (rev 151):
+ Ported to HP-UX.
+ Ported to Windows (both Cygwin and Mingw32) except the plugin system.
+ More bugs fixed.
* New in 3.99.1 prerelease (rev 126):
+ Ported to Mac OS X.
+ Added proper checks for the libraries (libgdbm, X11, Motif, ...).
+ Added a ChangeLog file.
+ libelf is no longer an absolute requirement, though it is still
strongly recommended.
* New in 3.99.0 prerelease (rev 96):
+ libelk, a shared library containing all the Elk scheme interpreter
features.
+ Properly builds with GCC 3.
+ 64 bits clean.
+ Uses autoconf, automake and libtool for greater portability and a
simpler build and installation process.
+ Support for dynamically loadable plugins. Previous versions used the
system's linker to build shared objects at runtime.
+ Massive bugfixing.
+ Dump support was removed because it was too platform-specific and
could not be thoroughly tested. I may enable it again in the future.
Changes between 2.2 and 3.0:
----------------------------
General:
* A new C/C++ Programmer's Manual for Elk is now available
(60+ pages with many examples). See doc/README (item `cprog')
and doc/cprog.
* The documentation has been prepared for translation to HTML
using the (Elk-based) `unroff' package.
* Elk now uses a new Scheme object representation (a `struct' rather
than an `unsigned long') to make it work on 64-bit architectures
and to allow for larger heaps, a wider range of fixnums, and more
first-class Scheme types.
* As a consequence, the `pointer_constant_high_bits' are gone, as
is util/pchb.c.
* Elk has been ported to and tested on these new platforms (config
files are included in the distribution):
DEC/Alpha, OSF/1
HP 9000, HP-UX 10.0
i386/486, BSDI BSD/OS
i386/486, Linux
IBM PowerPC, AIX 4.1
* A number of config files for obsolete platforms have been removed
from the distribution; config files for platforms where Elk 3.0
could not be tested are in config/untested. util/sgihack.c is gone.
* Extension initialization and finalization functions now begin
with `elk_init_' rather than just `init_' to avoid name conflicts.
* The directory `contrib' has been removed from the distribution,
as most of the contributions either were no longer maintained
or have been made an official part of the distribution.
contrib/eval-string is now available as lib/misc/elk-eval.c.
* Site/platform-specific information such as the various X11 `load
libraries', machine name, operating system name, as well as the
Elk version number are now available as Scheme variables in
scm/siteinfo.scm. The file is created automatically and can be
loaded via `(require 'siteinfo)'.
* Most of the improvements in scm/debug-new.scm have been merged
into the baseline debug.scm and the former has been removed.
The inspector now starts at the correct frame when called after
an error.
* examples/CC/class.c is a simple Elk extension demonstrating
encapsulation of a C++ class in a Scheme type.
* The file README has been renamed ROADMAP; RELEASE is now README.
Interpreter kernel:
* Many bugs have been fixed, and the code has been made `64-bit clean'.
* New functions for application writers to read/set the `error tag'
displayed in error messages and the application name (Get_Error_Tag,
Set_Error_Tag, Set_App_Name).
* When dynamically loading objects, the C++ static constructors are
now called _before_ all extension initializers. Ditto for C++
destructors and extension finalizers.
* New function for application/extension writers to load a file
whose name is given as a C string (Load_File).
* Load_Source_Port has been made `official' and may be used from
outside the interpreter.
* New functions for application/extension writers to convert
Scheme numbers to C unsigned int/long: Get_Unsigned,
Get_Unsigned_Long, Get_Exact_Unsigned, Get_Exact_Unsigned_Long.
New function Get_Exact_Long.
* The `round' primitive now rounds to even for numbers halfway
between two integers.
* The reader doesn't impose a limit on the length of strings and
symbols any longer.
* The dynamic loading implementations now use the environment
variable TMPDIR if present.
* `dump' now works under SGI Irix 5.x.
* New constants ELK_MINOR and ELK_MAJOR for application/extension
writers.
* Symbols containing special characters now print correctly when
output with `write'.
* Various optimizations in the interpreter's inner loop to compensate
for the performance loss caused by the struct-based object
representation on some platforms.
Extensions:
* The X11 extensions now work with X11 Release 6, Sun OpenWindows 3.x,
and Sun Motif.
* Extension-specific include files (unix.h, xlib.h, xt.h) are now
installed in a subdirectory $install_dir/include/extensions
for use by applications.
* The object files for Athena or Motif widgets are now loaded
by means of `require'.
* New POSIX-style regular expression extension (see doc/regexp and
examples/regexp).
* The file hunk.c has been removed from lib/misc, as it no longer
serves any purpose.
* Several bugs have been fixed in the UNIX and X11 extensions.
Changes between 2.1 and 2.2:
----------------------------
General:
* Elk ported to new platforms: SGI Irix 5.1, HP-UX 9.0
* All Scheme files now end with the suffix `.scm'
* Introduced new symbols in the config files to be used by the
UNIX extension
* Reorganized the include files. Split external declarations
into `private' (intern.h) and `public' (extern.h) declarations
to be used by extensions
* It's no longer necessary to specify multiple destination
directories in the site file (only install_dir; subdirectories
are created automatically)
* `init_objects' is gone from the site file, see INSTALL for a
new, simpler way to link extensions or an application with Elk
statically
* New directory $install_dir/lib is created with files module.o,
standalone.o and shell scripts linkscheme, makedl, and ldflags
(see INSTALL)
* Elk can now be used by applications that must have their own
main() function. See INSTALL for details.
Interpreter kernel:
* New primitives to allow blocking of signals from within Scheme
code: disable-interrupts, enable-interrupts
* Changed Disable_Interrupts and Enable_Interrupts macros to
allow nesting and to handle signals used by extensions
(specifically by the new UNIX extension)
* Extended representation of continuations to carry current
interrupt nesting level and restore it when being called
* (Re-)enable interrupts in toplevel on error
* Added default signal handlers for SIGPIPE and SIGHUP to clean
up temporary files
* New primitive: `features'
* `require' now appends .scm to feature name to obtain file name
(if no file name has been specified and if the feature name
doesn't have a suffix yet)
* Features elk:dump and elk:load-object are provided by the
interpreter if dump and dynamic loading are supported
* Implemented Register_Onfork() and Call_Onfork() to provide
`fork handlers' (used, for instance, by the UNIX extension)
* Added fork handlers to the dynamic loading implementations to
create links for the temporary files
* Added a close function to I/O ports to allow for pipe-based ports
* New primitive: char-ready?
* Added a check to the code that restarts a dumped interpreter
to detect that the start address of the stack has been moved
with respect to the original invocation (this happens between
Sun-4c and Sun-4m architectures, for instance)
* Modified math.c to implement the distinction between exact and
inexact numbers as required by the language definition
* New primitives: exact->inexact, inexact->exact
* The number prefixes #e and #i are now supported
* Floating point numbers are no longer automatically reduced to
integers; new conversion function Make_Flonum(double) in
addition to Make_Reduced_Flonum(double)
* Added new conversion functions to cleanly distinguish between
C ints and longs: Get_Long(Object), Make_Long(long),
Make_Unsigned_Long(unsigned long), and functions to convert
bignums from/to C longs
* New conversion functions for exact integers:
Get_Exact_Integer(Object) and Get_Exact_Long(Object)
* Removed the unique `void' type; #v is now converted into the empty
symbol by the reader; void? remains for compatibility
* Implemented reader table for #-syntax
* New function Define_Reader() to allow extensions to register
their own read syntaxes (used by the new bitstring extension)
* Exported parts of the reader to simplify writing new reader
functions in extensions
* New functions/macros to convert Scheme strings and/or symbols
into C strings (to be used by extension writers): Get_String,
Get_Strsym, Get_String_Stack, Get_Strsym_Stack; see src/cstring.c
* Now obsolete: Declare_C_Strings, Dispose_C_Strings, Make_C_String
* Bug fixes:
o fixed a few bugs in the implementation of continuations and
tail call optimization and in the generational, incremental
garbage collector
o there was a bug in the interaction between the garbage
collector and `dump'
o identified additional critical sections to be protected
from delivery of signals
o initscheme.scm wasn't resolved against the load-path
o quasiquotation now also works for vectors (kudos to
Tor Lillqvist for suggesting a simple fix)
o a bug in src/load-ld.c could cause the first static variable
in a dynamically loaded .o file to not be zeroed
Extensions:
* New UNIX extension; see doc/unix for the reference manual and
examples/unix for a few demonstration programs
* New record extension; see doc/record for the reference manual.
The `struct' extension is now obsolete
* New arbitrary-length bitstring extension; see doc/bitstring
for the manual
Changes between 2.0 and 2.1:
----------------------------
General:
* New configuration files for the 386/486-PC running 386BSD and
DOS/DJGPP, for Suns running Solaris 2.1 (SunOS 5.1, and for
the Convex C230 running ConvexOS.
* Reorganized the config files and the site file to allow for
configuration of the generational, incremental garbage collector
* Introduced several new symbols in the config files to simplify
installation on several systems
* Added new targets to all Makefiles to allow `cross-localization'
of the source tree (see comments in DOS section in MACHINES)
Interpreter kernel:
* Added a generational, incremental garbage collector
* New primitives: garbage-collect-status, collect-incremental
* Reorganized the source files to accommodate the new garbage
collector and to separate garbage collector specific code
from code common to both garbage collectors
* Empty list no longer counts as false; added primitive
`empty-list-is-false-for-backward-compatibility'
* Changed delimiter character in load-path argument of -p option
from comma to colon
* Initialize load-path from ELK_LOADPATH environment variable
(if present)
* Added argument to -v option to control which messages to print
(linker command, init/finit functions)
* It's no longer considered an error if an object file contains
no initializers
* Completely rewritten implementations of `dump' for ELF (SysVR4,
Solaris 2.x), ECOFF (Ultrix, Irix), and HP9000 a.out formats;
the HP version now correctly handles shared libraries
* Added support for dynamic loading under SysVR4 and Solaris 2.x
(see comments in MACHINES)
* Added code to read symbol table of object files on the Convex
* Bug fixes:
o dynamic-wind was completely broken; fixed it
o fixed a bug in the code that checks for the stack growing
direction (caused dumped images to crash on startup)
o fixed a bug in the equal? predicate (could enter an
infinite loop when applied to environments)
* Fixed a number of portability problems, among them:
o added O_BINARY flag to open() calls and "b" mode to fopen()
calls where necessary
o added support for the many different ways to purge a file
pointer and tty file descriptor (src/read.c, src/print.c)
* Integrated the functionality of the `libutil.a' library from
older releases into the interpreter kernel (conversion of
symbols and lists of symbols to bit masks and vice versa;
routines to manage a pool of weak pointers to objects, used
mainly by the Elk X extensions
Extensions:
* Removed libutil.a (lib/util/*); moved the code into the
interpreter kernel (src/terminate.c; src/symbol.c); removed
libutil.a from the default load-libraries
* Renamed lib/misc/c++.[co] to lib/misc/newhandler.[co] (c++.c isn't
a valid filename under DOS)
* Added finit function to lib/misc/monitor.c to switch off
monitoring and write mon.out on exit
Elk/X:
* The X extensions are no longer pre-linked against the required
X libraries (by means of ld -r); resolving against system libs
now always takes place at load time
* make-gcontext and copy-gcontext now can be called with a drawable
(i.e. pixmap or window)
* New primitives: alloc-color alloc-named-color
* Removed window-unique-id primitive
* Fixed a few bugs in the Xt extension (editres now works with
Scheme programs); removed an artificial limitation
* Defined a GC visit function for widgets that visits each widget's
parents and the children of composite widgets
* Added support for Motif gadgets
Changes between 1.5 and 2.0:
----------------------------
General:
* The build and install process has been improved significantly (see
file INSTALL)
* Added a new directory "config" that holds the system-specific
configuration files and the site-file
* Added a build shell script and a unified Makefile to all
directories; "build" creates the ``real'' Makefiles containing
system- and site-specific details during the make process
* Added install, lint, clean, and distclean targets to all
Makefiles
* Placed files that are needed during runtime (dynamically loadable
object files, Scheme files, the interpreter itself) into separate
directories; added "make install" to put files there
* Simplified porting Elk to new systems (assembly language support
and a stack-extending version of "alloca" are no longer required)
* Tested on several new systems (IBM RS/6000, HP9000/700, SGI,
Sony; see the file MACHINES)
* Placed new files CONTRIBUTORS, MIGRATE, and TODO into the toplevel
directory of the distribution
* Added a directory "util" that contains tools to simplify porting
Elk to new environments and other utilities that are useful on
some systems
* Added a directory "scripts" that holds the shell scripts used
to link instances of the interpreter and extensions.
* Removed "stk" directory with test programs (no longer needed)
* Added ANSI C prototypes and C++ "extern C" to all include files
Interpreter kernel:
* Placed include files into a separate directory (include)
* Reorganized the source files (separate source files for different
a.out formats and different dynamic loading mechanisms)
* Changed the way new Scheme objects are allocated to support the
generational garbage collector (not yet present in Elk)
* Rewrote the code implementing continuations to support full
call/cc on all machines
* Fixed tail recursion optimization
* Added support for POSIX signals (as alternative to BSD reliable
signals)
* Removed several artificial limitations (such as max. number of
before-GC and after-GC functions and statically GC-linked objects)
* Removed code that depended on max. number of open files per process
* Added bi-directional ports (input-output-ports); new primitive:
open-input-output-port
* New primitive: port-line-number
* Reader now prints line number on syntax error
* Max. length of a pathname is now determined correctly (using the
POSIX incantations if applicable)
* Added code to support dynamic loading under HP-UX (src/load-shl.c)
* Added code to call extension finalization functions and C++
destructors on termination
* Fixed and improved the code to call extension initialization
functions and C++ constructors on startup or when loading
extensions
* Improved the mechanism to suppress initialization of statically
linked extensions on startup ("dont_init_if_name" in config/site)
* Can use ANSI "atexit" as alternative to redefining "exit"
* Added option -p to specify load path
* Scheme file "initscheme" is now loaded before the toplevel is
loaded
* Changed "rand" to use rand() if random() isn't there
* re-entrant-continuations? primitive is no longer needed (returns
always #t now)
* Added a general mechanism to register termination functions for
individual objects (e.g. to close files on GC); see src/terminate.c
* linkscheme shell script improved; added code to support the
stupid AIX linker
* Fixed numerous things that caused lint or "gcc -ansi" to complain
* Changed the dynamic loading, "dump", and a.out symbol table reading
code in numerous places to make it work on new systems and to make
it more readable and maintainable
Extensions:
* Combined lib/util/symbol.o and lib/util/objects.o into new library
libutil.a; put this library into the default "load-libraries"
* Moved lib/util/string.c and lib/util/string.h into the interpreter
* Moved files from lib directory into new subdirectory "misc"
* Added POSIX sysconf stuff to unix.c to determine max. number of
open files per process
Elk/X:
* Made the code mostly "lint clean" and "gcc -ansi clean"
* Fixed bogus variable definitions in xlib.h and xt.h
* Xlib: added support for client-message event
* Xt: added code to avoid a bug in Motif 1.1.4
* Xt: added optional "mask" argument to context-add-input
* Removed site-dependent information from scm/xwidgets (file is
now created from scm/xwidgets.src during the build process)
* Renamed widget .d files that were longer than 14 characters;
added ALIASES file for each widget set containing mappings from
real widget names to short names
Documentation:
* Added sub-directory "paper" containing a draft version of a
paper about Elk
User-contributed extensions:
* A foreign function interface, an Elk Shell, and a vector extension
have been contributed by J. P. Lewis (contrib/zelk).
Changes between 1.4 and 1.5:
----------------------------
General:
* Added a "contrib" directory for user-contributed extensions
that I have not fully tested and/or integrated into Elk
* Renamed ORIGIN to COPYRIGHT
Interpreter kernel:
* Added support for the Amiga, A/UX and System V Release 4
(ELF a.out format)
* Added special load-library for MIPS (-lc_G0)
* Extension-interface: replaced Val() by Var_Set()/Var_Get()
* Modified load, autoload, and require so that multiple .o-files
can be loaded simultaneously
* Added -1+ as a synonym for 1-
* Bug fixes:
o fixed a GC-related bug
o fixed a bug that occurred when allocating a very large heap
o fixed a bug in case-insensitive string comparison
o fixed a bug in macro "when"
o changed and clarified semantics of print-depth/print-length
* IEEE 1178/R^4RS compatibility:
o replaced close-port by close-input-port and close-output-port
o added primitives caaaar .. cddddr
o added peek-char primitive
o added -i option for case-insensitive operation
* Removed -bc option
* Removed CBREAK-hack in read-char
Elk/X:
* Fixed several GC-related bugs (objects belonging to Xlib/Xt are
no longer terminated by garbage collector when unreferenced)
* Fixed a bug in the interface to the Grip widget
* Modified code to load widgets to make use of new capability to
load multiple .o-files
Documentation:
* Interpreter kernel: documented new functions, clarified
some sections
* Xlib/Xt: documented X-related behavior of garbage collector,
pointed out GC-related pitfalls
Changes between 1.3 and 1.4:
----------------------------
Interpreter kernel:
* Support for the NeXT machines added
* New primitive list? provided
* Two bugs in the tail recursion code fixed
* -v option to trace /bin/ld-calls
* man-page written
Elk/X:
* Tested under X11R5
* X11R3 and earlier versions are no longer supported
* The HP-widget code has been removed from the distribution
* New Xlib-primitives: install-colormap uninstall-colormap
list-installed-colormaps xlib-release-5-or-later?
* Xt interface now supports actions and accelerator tables
* Bug in set-context-fallback-resources! fixed
* New Xt-functions: widget-name widget-translate-coordinates
application-initialize context-add-action install-accelerators
install-all-accelerators xt-release-5-or-later?
* Support for new widget classes: menubutton panner porthole repeater
simplemenu sme smebsb smeline stripchart tree
* vpaned renamed to paned
* Example programs have been moved into a new examples directory
with sub-directories for Scheme, Xlib, Xaw, Motif
* New Xaw example programs that demonstrate the new widget classes,
accelerators, actions, etc.
Other extensions:
* Interface to the GNU gdbm-library