News
====
The last full release of the MIT Scheme system was version 7.1.3 in
1991. Since that time, there was a partial release of version 7.2 for
i386/i486 machines and some MIPS R3000 machines. This section
summarizes the changes that have occurred since version 7.1.3. The
changes are divided into two parts: those that were incorporated in the
7.2 partial release, and those that were subsequently incorporated.
Changes from Release 7.2 to 7.3
-------------------------------
This is an abbreviated list of the changes that have been
incorporated in the 7.3 release since the (partial) 7.2 release.
* Support for MS Windows (3.1 and NT).
* Native compiled-code support for DEC Alpha.
* Compiler can now generate C code. This is used to support the Sun
SPARC and IBM RS6000 architectures.
* Support for dynamic loading of compiled C code on several operating
systems, including HP-UX, OSF/1, SunOS 4, and AIX.
* New data structures: red/black trees and weight-balanced trees.
* Redesign of hash tables makes them much faster and somewhat more
flexible.
* Completely new random-number generator. The interface to the
random-number generator has been changed to be like that of Common
Lisp.
* Record abstraction now uses a special "record" type to represent
records (previously it used vectors). `define-structure' now
creates records by default; these records are identical to those
created with the record abstraction.
* `call-with-current-continuation' is now properly tail-recursive.
* New command-line switch `-no-suspend-file' prevents the generation
of `scheme_suspend' files.
* Uncompression of compiled-code debugging information is now
memoized to save time when doing many accesses to the same
information (a common occurrence).
* Constant space now grows automatically when needed.
* New procedures:
call-with-values ;replaces with-values
current-load-pathname
error-output-port
fold-left
fold-right
interaction-i/o-port
notification-output-port
prompt-for-command-char
prompt-for-command-expression
prompt-for-confirmation
prompt-for-evaluated-expression
prompt-for-expression
standard-unparser-method ;replaces unparser/standard-method
stream-first
stream-rest
symbol<?
trace-output-port
* `string-pad-left' now truncates from the left instead of the right.
* Argument to `make-graphics-device' is now a symbol.
* Each REPL now has its own working directory pathname and pathname
defaults. `set-working-directory-pathname!' changes only the value
for the current REPL.
* The definitions of the following procedures have been changed to
implement more useful behavior:
string-capitalized?
string-lower-case?
string-upper-case?
substring-capitalized?
substring-lower-case?
substring-upper-case?
* New Edwin features:
`M-x dabbrev-expand'
`M-x describe-syntax'
`M-x rcs-ci-locked-files'
`M-x rcs-diff'
`M-x rcs-list-locked-files'
`M-x rcs-log'
`M-x recover-file'
`M-x show-parameter-list'
`M-x sort-lines and other sorting commands'
`auto-mode-alist' variable (as in Emacs)
Encryption/decryption of files in `Dired'
Undo upgraded to match GNU Emacs 18.57
Buffers grow/shrink with constant amortized time
Emacs 19 tags support (multiple tags files, inclusion)
* Edwin compression/uncompression commands changed to use `gzip'
instead of `compress'.
* Edwin now has text-properties mechanism that permits implementation
of highlighted and mouse-sensitive regions.
Changes from Release 7.1 to 7.2
-------------------------------
This is an abbreviated list of the changes that were incorporated in
the (partial) 7.2 release since the 7.1 release.
* Support for MS DOS.
* Native compiled-code support for the Intel i386 and i486
architectures.
* Fixes to MIPS compiled-code support MIPS R3000 with large
cache-line sizes.
* Complete redesign of the error system.
* X11 graphics interface redesigned. The new design is smarter about
interaction with the window manager (for example, it implements the
`WM_DELETE_WINDOW' protocol) and has some limited support for event
handling. Windows are now closed when they are reclaimed by the
garbage collector.
* Redesign of I/O ports. New design supports ports that perform both
input and output.
* Ports now have better-defined control over blocking mode and
terminal mode. Flushing of output buffers is not done
automatically, except for the console port.
* New procedures:
*default-pathname-defaults*
->namestring
->truename
close-port
directory-namestring
directory-pathname
directory-pathname-as-file
enough-namestring
enough-pathname
file-access
file-attributes-direct ;same as file-attributes
file-modification-time-direct
file-modification-time-indirect ;same as file-modification-time
file-namestring
file-pathname
file-readable?
host-namestring
i/o-port?
make-generic-i/o-port
make-i/o-port
open-i/o-file
pathname-simplify
pathname-wild?
pathname=?
port/copy
port/input-channel
port/operation
port/operation-names
port/output-channel
port/state
port?
record-copy
record-modifier ;replaces record-updater
set-port/state!
* `with-input-from-file' and `with-output-to-file' no longer close
the port when they are exited abnormally.
* Redefined `#!optional' and `#!rest' to be something distinct from
symbols.
* Strings now accept `"\NNN'" octal character escapes, much like
those in C.
* Redesign of pathname abstraction. New design is very similar to
the Common Lisp pathname abstraction.
* ->PATHNAME no longer accepts a symbol as an argument. Only
strings and pathnames are valid.
* Procedures eliminated:
canonicalize-input-filename
canonicalize-input-pathname
canonicalize-output-filename
canonicalize-output-pathname
canonicalize-overwrite-filename
canonicalize-overwrite-pathname
home-directory-pathname
init-file-truename
pathname->absolute-pathname
pathname->input-truename
pathname->output-truename
pathname->overwrite-truename
pathname->string
pathname-components
pathname-default-host
pathname-directory-path
pathname-directory-string
pathname-name-path
pathname-name-string
pathname-new-host
pathname-relative?
string->pathname
symbol->pathname
* `pathname-default' no longer accepts a HOST argument.
* Representation of pathname directories changed to match
Common Lisp. Directory is now either `#f' or a list of
symbols and strings with first element either `absolute' or
`relative'.
* Unix pathnames now set DEVICE and VERSION to `unspecific'.
`unspecific' now means that the field is not used by the
operating system.
* Parsing rules for unix filenames changed: the file type is
the part of the name after the last dot, if any. If the dot
occurs at the beginning or end of the filename, then it
doesn't count -- in that case there is no type. Thus, names
like `.' and `..' have no type.
* New Edwin features:
`M-x manual-entry'
`M-x outline-mode'
`M-x shell-resync-dirs'
`M-x shell-command'
`M-x shell-command-on-region'
`M-x telnet'
RMAIL summary
RMAIL sort
REPL mode and asynchronous evaluation
Printing commands
``run light'' for evaluation commands
Reading and writing of compressed files (`".Z"' suffix)
Reading and writing of encrypted files (`".KY"' suffix)
Compress/uncompress commands for `Dired'
Support for X protocols: `WM_DELETE_WINDOW' and `WM_TAKE_FOCUS'
Time, load, and mail notification in mode line