[sbcl.git] / NEWS

changes in sbcl-0.6.0 relative to sbcl-0.5.0:

* tidied up "make.sh" script
* tidied up system directory structure
* better "clean.sh" behavior
* added doc/FOR-CMUCL-DEVELOPERS
* many many small tweaks to output format, e.g. removing possibly-confusing
  trailing #\. character in DESCRIBE-INSTANCE
* (EQUALP #\A 'A) no longer signals an error.
* new hashing code, including EQUALP hashing
* tidied up Lisp initialization and toplevel
* initialization files (e.g. /etc/sbclrc and $HOME/.sbclrc)
* command line argument processing
* added POSIX-GETENV function to deal with Unix-ish environment variables
* more-Unixy handling of *STANDARD-INPUT* and other Lisp streams, e.g.
  terminating SBCL on EOF
* non-verbose GC by default
* There is no more "sbcl" shell script; the sbcl file is now the C
  runtime executable (just like CMU CL).
* removed some unused fops, e.g. FOP-UNIFORM-VECTOR, FOP-CHARACTER, and 
  FOP-POP-FOR-EFFECT
* tweaked debug-info.lisp and debug-int.lisp to make the debugger store
  symbol and package information as Lisp native symbol and package objects
  instead of strings naming symbols and strings naming packages. This way,
  whenever packages are renamed (as in warm init), debug information is
  transformed along with everything else.
* tweaked the optimization policy declarations which control the building
  of SBCL itself. Now, among other things, the system no longer saves
  source location debugging information. (This helps two problems at once
  by reducing SBCL size and by keeping SBCL from trying to look for its
  sources -- which may not exist -- when reporting errors.)
* added src/cold/chill.lisp, to let SBCL read its own cold sources for
  debugging and testing purposes
* cleaned up printing, making the printer call PRINT-OBJECT for
  instances, and using PRINT-UNREADABLE-OBJECT for most PRINT-OBJECT
  methods, giving nearly-ANSI behavior
* converted almost all special variables to use *FOO* naming convention
* deleted PARSE-TIME functionality, since it can be done portably
* moved some files out of cold init into warm init
* deleted DEFUN UNDEFINED-VALUE, replaced (UNDEFINED-VALUE) forms
  with (VALUES) forms
* regularized formatting of source files
* added an install.sh script
* fixed ridiculous memory usage of cross-compiler by making
  compiler/alloc.lisp not try to do pooling unless it can hook
  itself into the GC of the cross-compilation host. Now the system
  builds nicely on my old laptop.
* added :SB-ALLOC in target-features.lisp-expr
* deleted mention of :ANSI-DOC from target-features.lisp-expr (since it
  was not implemented)
* re-did condition handling and note reporting in the compiler. Notes
  are no longer handled by signalling conditions. Style warnings
  and warnings are handled more correctly and reported in such a way
  that it's easy to find one or the other in your output (so that you
  can e.g. figure out which of many problems caused COMPILE-FILE to 
  return FAILURE-P).
* changed the severity of several compiler warnings from full WARNING
  to STYLE-WARNING in order to conform with the ANSI spec; also changed
  compiler note reporting so that it doesn't use the condition system
  at all (and hence affects neither FAILURE-P nor WARNINGS-P in the 
  COMPILE-FILE command)
* made PROCLAIM and DECLAIM conform to ANSI. PROCLAIM is now an ordinary
  function. As a consequence, START-BLOCK and END-BLOCK declarations are
  no longer supported, since their implementation was deeply intertwingled
  with the magical, non-ANSI treatment that PROCLAIM received in CMU CL.
* removed bogus "support" for compiler macros named (SETF FOO), and
  removed the compiler macro for SETF INFO (but only after making a fool
  of myself on the cmucl-imp mailing list by posting a bogus patch for
  DEFINE-COMPILER-MACRO..)
* Compiled files containing forms which have side effects on the Lisp
  reader (such as DEFPACKAGE forms) are now handled more correctly.
  (Compiler queuing of top level lambdas has been suppressed by setting
  *TOP-LEVEL-LAMBDA-MAX* to 0. )
* deleted various currently-unused source files, e.g. gengc.lisp. They
  may be added back at some point e.g. when porting to other architectures,
  but until they are it's distracting to distribute them and to try to
  maintain them.
* deleted "UNCROSS couldn't recurse through.." style warnings, since 
  there were so many of them they're just distractions, and UNCROSS is
  known to be able to handle the current sources
* moved PROFILE functionality into TRACE, so that it will be clear
  how the wrapping and unwrapping of functions when you profile them
  interacts with the wrapping and unwrapping of functions when you
  trace them. (Actually, the functionality isn't there yet, but at least
  the interface specification is there. Hopefully, the functionality will
  arrive with some future maintenance release.)
* removed host-oops.lisp
* changed signature of QUIT function to allow UNIX-CODE argument
* fixed READ-SEQUENCE bug
* tweaked verbose GC output so that it looks more like the progress
  output that ANSI specifies for functions like LOAD
* set up the system on sourceforge.com, with home pages, mailing lists, etc.
* added <http://sbcl.sourceforge.com> to the banner information printed by
  the sbcl executable

changes in sbcl-0.6.1 relative to sbcl-0.6.0:

* changed build optimization from (SAFETY 1) to (SAFETY 3) as a short-term
  fix for various type-unsafety bugs, e.g. failures with (LENGTH 123) and
  (MAKE-LIST -1). In the longer term, it ought to become true
  that declarations are assertions even at SAFETY 1. For now, it's not
  quite true even at SAFETY 3, but it's at least more nearly true..
  (Note that this change seems to increases the size of the system by
  O(5%) and to decrease the speed of the compiler by 20% or more.)
* changed ALIEN printing to be much more abbreviated, as a short-term fix
  for the problem of printing dozens of lines of distracting information
  about low-level system machinery as part of the top stack frame
  on entry to the debugger when an undefined function was called.
* tweaked the debugger's use of WITH-STANDARD-IO-SYNTAX so that *PACKAGE*
  is not reset to COMMON-LISP-USER. 
* Compilation of stuff related to dyncount.lisp has been made conditional
  on the :SB-DYNCOUNT target feature, so that the ordinary core system is
  smaller. The various dyncount-related symbols have been moved into
  a new "SB-DYNCOUNT" package.
* tty-inspect.lisp has been renamed to inspect.lisp.
* unix-glibc2.lisp has been renamed to unix.lisp, and the :GLIBC2
  feature has gone away. (When we eventually port to other flavors of 
  libc and/or Unix, we'll try to make the differences between flavors
  invisible at the user level.)
* Various other *FEATURES* tags, and/or their associated conditionals,
  have been removed if obsolescent, or given better documentation, or
  sometimes given more-mnemonic names.

changes in sbcl-0.6.2 relative to sbcl-0.6.1:

* (Note that the way that the PCL macroexpansions were rewritten
  to accommodate the change in DEFGENERIC below breaks binary
  compatibility. That is, fasl files compiled under sbcl-0.6.1 may
  not run under sbcl-0.6.2. Once we get out of alpha releases,
  i.e. hit release 1.0.0, we'll probably try to maintain binary
  compatibility between maintenance releases, e.g. between sbcl-1.4.3
  and sbcl-1.4.4. Until then, however, it might be fairly common
  for maintenance releases to break binary compatibility.)
* A bug in the calculation of WARNINGS-P and FAILURE-P in COMPILE-FILE
  has been fixed.
* The reporting of unhandled signals has been changed to print some
  explanatory text as well as the report form. (Previously only
  the report form was printed.)
* The macroexpansion for DEFGENERIC now DECLAIMs the function that
  it defines, so that the compiler no longer issues undefined function
  warnings for compiled-but-not-yet-loaded generic functions. 
* The CLTL-style "LISP" and "USER" nicknames for the "COMMON-LISP"
  and "COMMON-LISP-USER" packages have been removed. Now only the "CL"
  and "CL-USER" standard nicknames from the "11.1.2 Standardized Packages"
  section of the ANSI spec are supported.
* The "" nickname for the "KEYWORD" package has been removed. 
  The reader still handles symbol tokens which begin with a package marker
  as keywords, but it doesn't expose its mechanism for doing so in the
  (PACKAGE-NICKNAMES (FIND-PACKAGE "KEYWORD")) list.
* The system now issues STYLE-WARNINGs for contradictory TYPE 
  proclamations. (Warnings for contradictory FTYPE proclamations would
  be nice too, but those can't be done usefully unless the type system
  is made smarter about FUNCTION types.)
* The names of source files "*host-*.lisp" and "*target-*.lisp" have been 
  systematized, so that "*target-*.lisp is supposed to exist only on the
  target and imply that there's a related file which exists on the
  host, and *host-*.lisp is supposed to exist only on the host and imply
  that there's a related file which exists on the target. This involves a
  lot of renaming. Hopefully the acute confusion caused by the renaming
  will be justified by the reduction in chronic confusion..
  ** runtime-type.lisp    -> early-target-type.lisp
  ** target-type.lisp     -> late-target-type.lisp
  ** early-host-format.lisp -> early-format.lisp
  ** late-host-format.lisp -> late-format.lisp
  ** host-error.lisp      -> misc-error.lisp
  ** early-error.lisp     -> early-target-error.lisp
  ** late-error.lisp      -> late-target-error.lisp
  ** host-defboot.lisp    -> early-defboot.lisp
  ** code/misc.lisp       -> code/target-misc.lisp
  ** code/host-misc.lisp  -> code/misc.lisp
  ** code/numbers.lisp    -> code/target-numbers.lisp
  ** code/early-numbers.lisp -> numbers.lisp
  ** early-host-type.lisp -> early-type.lisp
  ** late-host-type.lisp  -> late-type.lisp
  ** host-typep.lisp      -> typep.lisp
  ** load.lisp            -> target-load.lisp
  ** host-load.lisp       -> load.lisp
  ** host-disassem.lisp   -> disassem.lisp
  ** host-insts.lisp      -> insts.lisp
  ** byte-comp.lisp       -> target-byte-comp.lisp
  ** host-byte-comp.lisp  -> byte-comp.lisp
  ** host-signal.lisp     -> signal.lisp
  ** host-defstruct.lisp  -> defstruct.lisp
  ** late-target-type.lisp -> deftypes-for-target.lisp
  Furthermore, several other previously target-only files foo.lisp (e.g.
  hash-table.lisp and random.lisp) have been split into a target-and-host
  foo.lisp file and a target-only target-foo.lisp file, with their key type
  definitions in the target-and-host part, so that the cross-compiler will
  know more about target types.
* DEFSTRUCT BACKEND, and the BACKEND-valued *BACKEND* variable, have 
  gone away. In their place are various *BACKEND-FOO* variables
  corresponding to the slots of the old structure.
* A bug which caused the SB-COLD bootstrap-time package to be propagated
  into the target SBCL has been fixed.
* The chill.lisp system for loading cold code into a running SBCL
  now works better.
* Support for the CMU CL "scavenger hook" extension has been removed.
  (It was undocumented and unused in the CMU CL sources that SBCL was
  derived from, and stale in sbcl-0.6.1.)
* Various errors in the cross-compiler type system were detected
  by running the cross-compiler with *TYPE-SYSTEM-INITIALIZED*
  (enabling various consistency checks). Many of them were fixed,
  but some hard problems remain, so the compiler is back to 
  running without *TYPE-SYSTEM-INITIALIZED* for now.
* As part of the cross-compiler type system cleanup, I implemented
  DEF!TYPE and got rid of early-ugly-duplicates.lisp.
* I have started adding UNCROSS calls throughout the type system
  and the INFO database. (Thus perhaps eventually the blanket UNCROSS
  on cross-compiler input files will be able to go away, and various
  kludges with it).
* CONSTANTP now returns true for quoted forms (as explicitly required
  by the ANSI spec).

changes in sbcl-0.6.3 relative to sbcl-0.6.2:

* The system still can't cross-compile itself with
  *TYPE-SYSTEM-INITIALIZED* (and all the consistency checks that
  entails), but at least it can compile more of itself that way
  than it used to be able to, and various buglets which were uncovered
  by trying to cross-compile itself that way have now been fixed.
* This release breaks binary compatibility again. This time 
  at least I've incremented the FASL file format version to 2, so that the
  problem can be detected reliably instead of just causing weird errors.
* various new style warnings:
  ** using DEFUN, DEFMETHOD, or DEFGENERIC to overwrite an old definition
  ** using the deprecated EVAL/LOAD/COMPILE situation names in EVAL-WHEN
  ** using the lexical binding of a variable named in the *FOO* style
* DESCRIBE has been substantially rewritten. It now calls DESCRIBE-OBJECT
  as specified by ANSI.
* *RANDOM-STATE* is no longer automatically initialized from 
  (GET-UNIVERSAL-TIME), but instead from a constant seed. Thus, the
  default behavior of the system is to repeat its behavior every time
  it's run. If you'd like to change this behavior, you can always
  explicitly set the seed from (GET-UNIVERSAL-TIME); whereas under the 
  old convention there was no comparably easy way to get the system to 
  repeat its behavior every time it was run.
* Support for the pre-CLTL2 interpretation of FUNCTION declarations as
  FTYPE declarations has been removed, in favor of their ANSI
  interpretation as TYPE FUNCTION declarations. (See p. 228 of CLTL2.)
* The quantifiers SOME, EVERY, NOTANY, and NOTEVERY no longer cons when
  the types of their sequence arguments can be determined at compile time.
  This is done through a new open code expansion for MAP which eliminates
  consing for (MAP NIL ..), and reduces consing otherwise, when sequence
  argument types can be determined at compile time.
* The optimizer now transforms COERCE into an identity operation when it 
  can prove that the coerced object is already of the correct type. (This 
  can be a win for machine generated code, including the output of other
  optimization transforms, such as the MAP transform above.)
* Credit information has been moved from source file headers into CREDITS.
* Source file headers have been made more standard.
* The CASE macro now compiles without complaining even when it has
  no clauses.

changes in sbcl-0.6.4 relative to sbcl-0.6.3:

* There is now a partial SBCL user manual (with some new text and some
  text cribbed from the CMU CL manual). 
* The beginnings of a profiler have been added (starting with the
  CMU CL profiler and simplifying and cleaning up). Eventually the
  main interface should be through the TRACE macro, but for now, 
  it's still accessed through vaguely CMU-CL-style functions and macros
  exported from the package SB-PROFILE.
* Some problems left over from porting CMU CL to the new
  cross-compilation bootstrap process have been cleaned up:
  ** DISASSEMBLE now works. (There was a problem in using DEFMACRO
     instead of SB!XC:DEFMACRO, compounded by an oversight on my 
     part when getting rid of the compiler *BACKEND* stuff.)
  ** The value of *NULL-TYPE* was screwed up, because it was
     being initialized before the type system knew the final
     definition of the 'NULL type. This screwed up several key
     optimizations in the compiler, causing inefficiency in all sorts
     of places. (I found it because I wanted to understand why
     GET-INTERNAL-RUN-TIME was consing.) 
* fixed a bug in DEFGENERIC which was causing it to overwrite preexisting
  PROCLAIM FTYPE information. Unfortunately this broke binary 
  compatibility again, since now the forms output by DEFGENERIC
  to refer to functions which didn't exist in 0.6.3.
* added declarations so that SB-PCL::USE-CACHING-DFUN-P 
  can use the new (as of 0.6.3) transform for SOME into MAP into 
  inline code
* changed (MOD 1000000) type declarations for Linux timeval.tv_usec slot
  values to (INTEGER 0 1000000), so that the time code will no longer
  occasionally get blown up by Linux returning 1000000 microseconds
* PRINT-UNREADABLE-OBJECT has been tweaked to make the spacing of
  its output conform to the ANSI spec. (Alas, this makes its output
  uglier in the :TYPE T :IDENTITY NIL case, but them's the breaks.)
* A full call to MAP NIL with a single sequence argument no longer conses.
* fixes to problems pointed out by Martin Atzmueller:
  * The manual page no longer talks about multiprocessing as though
    it were currently supported.
  * The ILISP support patches have been removed from the distribution,
    because as of version 5.10.1, ILISP now supports SBCL without us
    having to maintain patches.
* added a modified version of Raymond Toy's recent CMU CL patch for
  EQUALP comparison of HASH-TABLE

changes in sbcl-0.6.5 relative to sbcl-0.6.4:

* Raymond Wiker's patches to port the system to FreeBSD have been merged.
* The build process now looks for GNU make under the default name "gmake",
  instead of "make" as it used to. If GNU make is not available as "gmake"
  on your system, you can change this default behavior by setting the 
  GNUMAKE environment variable.
* Replace #+SB-DOC with #!+SB-DOC in seq.lisp so that the system 
  can build without error under CMU CL.

changes in sbcl-0.6.6 relative to sbcl-0.6.5:

* DESCRIBE no longer tries to call itself recursively to describe
  bound/fbound values, so that it no longer fails on symbols which are
  bound to themselves (like keywords, T, and NIL).
* DESCRIBE now works on generic functions.
* The printer now prints less-screwed-up representations of closures
  (not naively trying to bogusly use the %FUNCTION-NAME accessor on them).
* A private symbol is used instead of the :EMPTY keyword previously 
  used to mark empty slots in hash tables. Thus 
        (DEFVAR *HT* (MAKE-HASH-TABLE))
        (SETF (GETHASH :EMPTY *HT*) :EMPTY)
        (MAPHASH (LAMBDA (K V) (FORMAT T "~&~S ~S~%" K V)))
  now does what ANSI says that it should. (You can still get 
  similar noncompliant behavior if bang on the hash table
  implementation with all the symbols you get back from 
  DO-ALL-SYMBOLS, but at least that's a little harder to do.)
  This breaks binary compatibility, since tests for equality to 
  :EMPTY are wired into things like the macroexpansion of 
  WITH-HASH-TABLE-ITERATOR in FASL files produced by earlier
  implementations.
* There's now a minimal placeholder implementation for CL:STEP,
  as required by ANSI.
* An obscure bug in the interaction of the normal compiler, the byte
  compiler, inlining, and structure predicates has been patched
  by setting the flags for the DEFTRANSFORM of %INSTANCE-TYPEP as
  :WHEN :BOTH (as per Raymond Toy's suggestion on the cmucl-imp@cons.org
  mailing list).
* Missing ordinary arguments in a macro call are now detected even
  when the macro lambda list contains &KEY or &REST.
* The debugger no longer complains about encountering the top of the
  stack when you type "FRAME 0" to explicitly instruct it to go to
  the top of the stack. And it now prints the frame you request even
  if it's the current frame (instead of saying "You are here.").
* As specified by ANSI, the system now always prints keywords
  as #\: followed by SYMBOL-NAME, even when *PACKAGE* is the
  KEYWORD package.
* The default initial SIZE of HASH-TABLEs is now smaller.
* Type information from CLOS class dispatch is now propagated
  into DEFMETHOD bodies, so that e.g.
        (DEFMETHOD FOO ((X SINGLE-FLOAT))
          (+ X 123.0))
  is now basically equivalent to 
        (DEFMETHOD FOO ((X SINGLE-FLOAT))
          (DECLARE (TYPE SINGLE-FLOAT X))
          (+ X 123.0))
  and the compiler can compile (+ X 123.0) as a SINGLE-FLOAT-only
  operation, without having to do run-time type dispatch.
* The macroexpansion of DEFMETHOD has been tweaked so that it has
  reasonable behavior when arguments are declared IGNORE or IGNORABLE.
* Since I don't seem to be making big file reorganizations very often
  any more (and since my archive of sbcl-x.y.zv.tar.bz2 snapshots
  is overflowing my ability to conveniently back them up), I've finally
  checked the system into CVS. (The CVS repository is on my home system,
  not at SourceForge -- putting it on SourceForge might come later.)
* SB-EXT:*GC-NOTIFY-STREAM* has been added, to control where the 
  high-level GC-NOTIFY-FOO functions send their output. (There's
  still very little control of where low-level verbose GC functions
  send their output.) The SB-EXT:*GC-VERBOSE* variable now controls
  less than it used to -- the GC-NOTIFY-FOO functions are now under
  the control of *GC-NOTIFY-STREAM*, not *GC-VERBOSE*.
* The system now stores the version string (LISP-IMPLEMENTATION-VERSION)
  in only one place in the source code, and propagates it automatically
  everywhere that it's needed. Thus e.g. when I bump the version from
  0.6.6 to 0.6.7, I'll only need to modify the sources in one place.
* The C source files now include boilerplate legalese and documentation
  at the head of each file (just as the Lisp source files already did).
* At Dan Barlow's suggestion, the hyperlink from the SBCL website
  to his page will be replaced with a link to his new CLiki service.

changes in sbcl-0.6.7 relative to sbcl-0.6.6:

* The system has been ported to OpenBSD.
* The system now compiles with a simple "sh make.sh" on the systems
  that it's supported on. I.e., now you no longer need to tweak 
  text in the target-features.lisp-expr and symlinks in src/runtime/
  by hand, the make.sh takes care of it for you.
* The system is no longer so grossly inefficient when compiling code
  involving vectors implemented as general (not simple) vectors (VECTOR T),
  so code which dares to use VECTOR-PUSH-EXTEND and FILL-POINTER, or
  which dares to use the various sequence functions on non-simple 
  vectors, takes less of a performance hit.
  * There is now a primitive type predicate VECTOR-T-P
    to test for the (VECTOR T) type, so that e.g.
        (DEFUN FOO (V) (DECLARE (TYPE (VECTOR T) V)) (AREF V 3))
    can now be compiled with some semblance of efficiency. (The old code
    turned the type declaration into a full call to %TYPEP at runtime!)
  * AREF on (VECTOR T) is still not fast, since it's still compiled
    as a full call to SB-KERNEL:DATA-VECTOR-REF, but at least the
    ETYPECASE used in DATA-VECTOR-REF is now compiled reasonably
    efficiently. (The old version made full calls to SUBTYPEP at runtime!)
  * (MAKE-ARRAY 12 :FILL-POINTER T) is now executed less inefficiently,
    without making full calls to SUBTYPEP at runtime.
  (Some analogous efficiency issues for non-simple vectors specialized to
  element types other than T, or for non-simple multidimensional arrays,
  have not been addressed. They could almost certainly be handled the
  same way if anyone is motivated to do so.)
* The changes in array handling break binary compatibility, so
  *BACKEND-FASL-FILE-VERSION* has been bumped to 4.
* (TYPEP (MAKE-ARRAY 12 :FILL-POINTER 4) 'VECTOR) now returns (VALUES T)
  instead of (VALUES T T).
* By following the instructions that Dan Barlow posted to sbcl-devel
  on 2 July 2000, I was able to enable primitive dynamic object
  file loading code for Linux. The full-blown CMU CL LOAD-FOREIGN
  functionality is not implemented (since it calls ld to resolve
  library references automatically, requiring RUN-PROGRAM for its
  implementation), but a simpler SB-EXT:LOAD-1-FOREIGN (which doesn't
  try to resolve library references) is now supported.
* The system now flushes the standard output streams when it terminates,
  unless QUIT is used with the RECKLESSLY-P option set. It also flushes
  them at several other probably-convenient times, e.g. in each pass of
  the toplevel read-eval-print loop, and after evaluating a form given
  as an "--eval" command-line option. (These changes were motivated by a
  discussion of stream flushing issues on cmucl-imp in August 2000.) 
* The source transform for TYPEP of array types no longer assumes
  that an array whose element type is a not-yet-defined type 
  is implemented as an array of T, but instead punts, so that the 
  type will be interpreted at runtime.
* There is now some support for cross-compiling in make.sh: each of
  the phases of make.sh has its own script. (This should be transparent
  to people doing ordinary, non-cross-compile builds.)
* Since my laptop doesn't have hundreds of megabytes of memory like
  my desktop machine, I became more motivated to do some items on
  my to-do list in order to reduce the size of the system a little:
  ** Arrange for various needed-only-at-cold-init things to be
     uninterned after cold init. To support this, those things have
     been renamed from FOO and *FOO* to !FOO and *!FOO* (i.e., all
     symbols with such names are now uninterned after cold init).
  ** Bind SB!C::*TOP-LEVEL-LAMBDA-MAX* to a nonzero value when building
     fasl files for cold load.
  ** Remove the old compiler structure pooling code (which used to 
     be conditional on the target feature :SB-ALLOC) completely.
  ** Redo the representation of some data in cold init to be more compact.
  (I also looked into supporting byte compiled code at bootstrap time,
  which would probably reduce the size of the system a lot, but that
  looked too complicated, so I punted for now.)
* The maximum signal nesting depth in the src/runtime/ support code has
  been reduced from 4096 to 256. (I don't know any reason for the very
  large old value. If the new smaller value turns out to break something,
  I'll probably just bump it back up.)
* PPRINT-LOGICAL-BLOCK is now pickier about the types of its arguments,
  as per ANSI.
* Many, many bugs reported by Peter Van Eynde have been added to
  the BUGS list; some have even been fixed.
* While enabling dynamic object file loading, I tried to make the 
  code easier to understand, renaming various functions and variables
  with less ambiguous names, and changing some function calling
  conventions to be Lispier (e.g. returning NIL instead of 0 for failure).
* While trying to figure out how to do the OpenBSD port, I tried to 
  clean up some of the code in src/runtime/. In particular, I dropped
  support for non-POSIX signal handling, added various comments, 
  tweaked the code to reduce the number of compilation warnings, and
  renamed some files to increase consistency.
* To support the new automatic configuration functionality in make.sh,
  the source file target-features.lisp-expr has been replaced with the
  source file base-target-features.lisp-expr and the machine-generated
  file local-target-features.lisp-expr.
* fixed a stupid quoting error in make.sh so that using CMU CL
  "lisp -batch" as cross-compilation host works again

changes in sbcl-0.6.8 relative to sbcl-0.6.7:

* The system is now under CVS at SourceForge (instead of the
  CVS repository on my home machine).
* The new signal handling code has been tweaked to treat register
  contents as (UNSIGNED-BYTE 32), as the old CMU CL code did,
  instead of (SIGNED-BYTE 32), as the C header files have it. (Code 
  downstream, e.g. in debug-int.lisp, has implicit dependencies
  on the unsignedness of integer representation of machine words, 
  and that caused the system to bomb out with infinite regress
  when trying to recover from type errors involving signed values,
  e.g. (BUTLAST '(1 2 3) -1).)
* (BUTLAST NIL) and (NBUTLAST NIL) now return NIL as they should.
  (This was one of the bugs Peter Van Eynde reported back in July.)
* The system now uses code inspired by Colin Walters' O(N)
  implementation of MAP (from the cmucl-imp@cons.org mailing
  list, 2 September 2000) when it can't use a DEFTRANSFORM to
  inline the MAP operation, and there is more than one
  sequence argument to the MAP call (so that it can't just
  do ETYPECASE once and for all based on the type of the
  single sequence argument). (The old non-inline implementation
  of the general M-argument sequence-of-length-N case required
  O(M*N*N) time when any of the sequence arguments were LISTs.)
* The QUIT :UNIX-CODE keyword argument has been renamed to 
  QUIT :UNIX-STATUS. (The old name still works, but is deprecated.)
* Raymond Wiker's patches to port RUN-PROGRAM from CMU CL to SBCL
  have been added.
* Raymond Wiker's patches to port dynamic loading from Linux to
  FreeBSD have been added.
* The BUGS file is now more nearly up to date, thanks in large part
  to Martin Atzmueller's review of it.
* The debugger now flushes standard output streams before it begins
  its output ("debugger invoked" and so forth).
* The core version number and fasl file version number have both
  been incremented, because of incompatible changes in the layout
  of static symbols.
* FINISH-OUTPUT is now called more consistently on QUIT. (It
  used to not be called for a saved Lisp image.)
* Martin Atzmueller's version of a patch to fix a compiler crash,
  as posted on sbcl-devel 13 September 2000, has been installed.
* Instead of installing Martin Atzmueller's patch for the
  compiler transform for SUBSEQ, I deleted the compiler transform,
  and transforms for some similar consing operations.
* A bug in signal handling which kept TRACE from working on OpenBSD
  has been fixed.
* added enough DEFTRANSFORMs to allow (SXHASH 'FOO) to be optimized
  away by constant folding
* The system now defines its address space constants in one place
  (in the Lisp sources), and propagates them automatically elsewhere
  (through GENESIS and the sbcl.h file). Therefore, patching the
  address map is less unnecessarily tedious and error-prone. The
  Lisp names of address space constants have also been systematized.
* CVS tags like dollar-Header-dollar have been removed from
  the sources, because they have never saved me trouble and
  they've been source of trouble working with patches and other
  diff-related operations.
* fixed the PROG1-vs.-PROGN bug in HANDLER-BIND (reported by 
  ole.rohne@cern.ch on cmucl-help@cons.org 2000-10-25)

changes in sbcl-0.6.9 relative to sbcl-0.6.8:

* DESCRIBE now works on CONDITION objects.
* The debugger now handles errors which arise when trying to print
  *DEBUG-CONDITION*, so that it's less likely to fall into infinite
  regress.
* The build system now uses an additional file, customize-target-features.lisp,
  to allow local modifications to the target *FEATURES* list. (The point of
  this is that now I can set up a custom configuration, e.g. with :SB-SHOW
  debugging features enabled, without having to worry about propagating it
  into everyone's system when I do a "cvs update".) When no
  customize-target-features.lisp file exists, the target *FEATURES* list
  should be constructed the same way as before.
* fixed bugs in DEFCONSTANT ANSI-compatibility:
  ** DEFCONSTANT now tests reassignments using EQL, not EQUAL, in order to 
     warn about behavior which is undefined under the ANSI spec. Note: This
     is specified by ANSI, but it's not very popular with programmers.
     If it causes you problems, take a look at the new SB-INT:DEFCONSTANT-EQX
     macro in the SBCL sources for an example of a workaround which you
     might use to make portable ANSI-standard code which does what you want.
  ** DEFCONSTANT's implementation is now based on EVAL-WHEN instead of on
     pre-ANSI IR1 translation magic, so it does the ANSI-specified thing
     when it's used as a non-toplevel form. (This is required in order
     to implement the DEFCONSTANT-EQX macro.)
  ** (DEFCONSTANT X 1) (DEFVAR X) (SETF X 2) no longer "works".
  ** Unfortunately, non-toplevel DEFCONSTANT forms can still do some
     funny things, due to bugs in the implementation of EVAL-WHEN
     (bug #IR1-3). This probably won't be fixed until 0.7.x. (Fortunately,
     non-toplevel DEFCONSTANTs are uncommon.)
* The core file version number and fasl file version number have been 
  incremented, because the old noncompliant DEFCONSTANT behavior involved
  calling functions which no longer exist, and because I also took the
  opportunity to chop an unsupported slot out of the DEBUG-SOURCE structure.
* fixed bug 1 (error handling before read-eval-print loop starts), and
  redid debugger restarts and related debugger commands somewhat while
  doing so:
  ** The QUIT debugger command is gone, since it did something
     rather different than the SB-EXT:QUIT command, and since it never
     worked properly outside the main toplevel read/eval/print loop.
     Invoking the new TOPLEVEL restart provides the same functionality.
  ** The GO debugger command is also gone, since you can just invoke
     the CONTINUE restart directly instead.
  ** The TOP debugger command is also gone, since it's redundant with the
     FRAME 0 command, and since it interfered with abbreviations for the
     TOPLEVEL restart.
* The system now recovers better from non-PACKAGE values of the *PACKAGE*
  variable.
* The system now understands compound CONS types (e.g. (CONS FIXNUM T))
  as required by ANSI. (thanks to Douglas Crosher's CMU CL patches, with
  some porting work by Martin Atzmueller)
* Martin Atzmueller reviewed the CMU CL mailing lists and came back
  with a boatload of patches which he ported to SBCL. Now that those
  have been applied,
  ** The system tries to make sure that its low-priority messages
     are prefixed by semicolons, to help people who like to use
     syntax highlighting in their ILISP buffer. (This patch
     was originally due to Raymond Toy.)
  ** The system now optimizes INTEGER-LENGTH better, thanks to more
     patches originally written by Raymond Toy.
  ** The compiler understands coercion between single-value and 
     multiple-VALUES type expressions better, getting rid of some very
     weird behavior, thanks to patches originally by Robert MacLachlan
     and Douglas Crosher.
  ** The system understands ANSI-style non-KEYWORD &KEY arguments in 
     lambda lists, thanks to a patch originally by Pierre Mai.
  ** The system no longer bogusly warns about "abbreviated type
     declarations".
  ** The compiler gets less confused by inlining and RETURN-FROM,
     thanks to some patches originally by Tim Moore.
  ** The system no longer hangs when dumping circular lists to fasl
     files, thanks to a patch originally from Douglas Crosher.
* Martin Atzmueller also fixed ROOM, so that it no longer fails with an
  undefined function error.
* gave up on fixing bug 3 (forbidden-by-ANSI warning for type mismatch
  in structure slot initforms) for now, documented workaround instead:-|
* fixed bug 4 (no WARNING for DECLAIM FTYPE of slot accessor function)
* fixed bug 5: added stubs for various Gray stream functions called
  in the not-a-CL:STREAM case, so that even when Gray streams aren't
  installed, at least appropriate type errors are generated
* fixed bug 8: better reporting of various PROGRAM-ERRORs
* fixed bug 9: IGNORE and IGNORABLE now work reasonably and more
  consistently in DEFMETHOD forms. 
* removed bug 21 from BUGS, since Martin Atzmueller points out that 
  it doesn't seem to affect SBCL after all
* The C runtime system now builds with better optimization and many
  fewer warnings, thanks to lots of cleanups by Martin Atzmueller.

changes in sbcl-0.6.10 relative to sbcl-0.6.9:

* A patch from Martin Atzmueller seems to have solved the SIGINT
  problem, and as far as we know, signal-handling now works cleanly.
  (If you find any new bugs, please report them!)
* The system no longer defaults Lisp source file names to types
  ".l", ".cl", or ".lsp", but only to ".lisp". 
* The compiler no longer uses special default file extensions for
  byte-compiled code. (The ANSI definition of COMPILE-FILE-PATHNAME
  seems to expect a single default extension for all compiled code,
  and there's no compelling reason to try to stretch the standard
  to allow two different extensions.) Instead, byte-compiled files
  default to the same extension as native-compiled files.
* Fasl file format version numbers have increased again, because
  a rearrangement of internal implementation packages made some 
  dumped symbols in old fasl files unreadable in new cores.
* DECLARE/DECLAIM/PROCLAIM logic is more nearly ANSI in general, with
  many fewer weird special cases.
* Bug #17 (differing COMPILE-FILE behavior between logical and 
  physical pathnames) has been fixed, and some related misbehavior too,
  thanks to a patch from Martin Atzmueller.
* Bug #30 (reader problems) is gone, thanks to a CMU CL patch
  by Tim Moore, ported to SBCL by Martin Atzmueller.
* Martin Atzmueller fixed several filesystem-related problems,
  including bug #36, in part by porting CMU CL patches, which were
  written in part by Paul Werkowski.
* More compiler warnings in src/runtime/ are gone, thanks to 
  more patches from Martin Atzmueller.
* Martin Atzmueller pointed out that bug 37 was fixed by his patches
  some time ago.

changes in sbcl-0.6.11 relative to sbcl-0.6.10:
* Martin Atzmueller pointed out that bugs #9 and #25 are gone in
  current SBCL.
* bug 34 fixed by Martin Atzmueller: dumping/loading instances works
  better
* fixed bug 40: TYPEP, SUBTYPEP, UPGRADED-ARRAY-ELEMENT-TYPE, 
  and UPGRADED-COMPLEX-PART-TYPE now work better with of compound
  types built from undefined types, e.g. '(VECTOR SOME-UNDEF-TYPE).
* DESCRIBE now works on structure objects again.
* Most function call argument type mismatches are now handled as
  STYLE-WARNINGs instead of full WARNINGs, since the compiler doesn't
  know whether the function will be redefined before the call is
  executed. (The compiler could flag local calls with full WARNINGs,
  as per the ANSI spec "3.2.2.3 Semantic Constraints", but right now
  it doesn't keep track of enough information to know whether calls
  are local in this sense.)
* Compiler output is now more verbose, with messages truncated
  later than before. (There should be some supported way for users
  to override the default verbosity, but I haven't decided how to 
  provide it yet, so this behavior is still controlled by the internal
  SB-C::*COMPILER-ERROR-PRINT-FOO* variables in
  src/compiler/ir1util.lisp.)
* Fasl file format version numbers have increased again, because
  support for the Gray streams extension changes the layout of the
  system's STREAM objects.
* The Gray subclassable streams extension now works, thanks to a 
  patch from Martin Atzmueller.
* The full LOAD-FOREIGN extension (not just the primitive
  LOAD-FOREIGN-1) now works, thanks to a patch from Martin Atzmueller.
* The default behavior of RUN-PROGRAM has changed. Now, unlike CMU CL
  but like most other programs, it defaults to copying the Unix
  environment from the original process instead of starting the
  new process in an empty environment.
* Extensions which manipulate the Unix environment now support
  an :ENVIRONMENT keyword option which doesn't smash case or 
  do other bad things. The CMU-CL-style :ENV option is retained
  for porting convenience.
* LOAD-FOREIGN (and LOAD-1-FOREIGN) now support logical pathnames,
  as per Daniel Barlow's suggestion and Martin Atzmueller's patch

changes in sbcl-0.6.12 relative to sbcl-0.6.11:
* incompatible change: The old SB-EXT:OPTIMIZE-INTERFACE declaration
  is no longer recognized. I apologize for this, because it was
  listed in SB-EXT as a supported extension, but I found that
  its existing behavior was poorly specified, as well as incorrectly
  specified, and it looked like too much of a mess to straighten it
  out. I have enough on my hands trying to get ANSI stuff to work..
* many patches ported from CMU CL by Martin Atzmueller, with 
  half a dozen bug fixes in pretty-printing and the debugger, and
  half a dozen others elsewhere
* fixed bug 13: Floating point infinities are now supported again.
  They might still be a little bit flaky, but thanks to bug reports
  from Nathan Froyd and CMU CL patches from Raymond Toy they're not
  as flaky as they were.
* The --noprogrammer command line option is now supported. (Its
  behavior is slightly different in detail from what the old man
  page claimed it would do, but it's still appropriate under the
  same circumstances that the man page talks about.)
* The :SB-PROPAGATE-FLOAT-TYPE and :SB-PROPAGATE-FUN-TYPE features
  are now supported, and enabled by default. Thus, the compiler can
  handle many floating point and complex operations much less
  inefficiently. (Thus e.g. you can implement a complex FFT
  without consing!)
* The compiler now detects type mismatches between DECLAIM FTYPE 
  and DEFUN better, and implements CHECK-TYPE more correctly, and
  SBCL builds under CMU CL again despite its non-ANSI EVAL-WHEN,
  thanks to patches from Martin Atzmueller.
* various fixes to make the cross-compiler more portable to
  ANSI-conforming-but-different cross-compilation hosts (notably
  Lispworks for Windows, following bug reports from Arthur Lemmens)
* A bug in READ-SEQUENCE for CONCATENATED-STREAM, and a gross
  ANSI noncompliance in DEFMACRO &KEY argument parsing, have been
  fixed thanks to Pierre Mai's CMU CL patches.
* fixes to keep the system from overflowing internal counters when
  it tries to use i/o buffers larger than 16M bytes
* fixed bug 45a: Various internal functions required to support
  complex special functions have been merged from CMU CL sources.
  (When I was first setting up SBCL, I misunderstood a compile-time
  conditional #-OLD-SPECFUN, and so accidentally deleted them.)
* improved support for type intersection and union, fixing bug 12
  (e.g., now (SUBTYPEP 'KEYWORD 'SYMBOL)=>T,T) and some other
  more obscure bugs as well
* some steps toward byte-compiling non-performance-critical
  parts of the system, courtesy of patches from Martin Atzmueller
* Christophe Rhodes has made some debian packages of sbcl at
  <http://www-jcsu.jesus.cam.ac.uk/ftp/pub/debian/lisp>.
  From his sbcl-devel e-mail of 2001-04-08 they're not completely
  stable, but are nonetheless usable. When he's ready, I'd be happy
  to add them to the SourceForge "File Releases" section. (And if
  anyone wants to do RPMs or *BSD packages, they'd be welcome too.)
* new fasl file format version number (because of changes in 
  internal representation of (OR ..) types to accommodate the new
  support for (AND ..) types, among other things)

changes in sbcl-0.6.13 relative to sbcl-0.6.12:
* a port to the Compaq/DEC Alpha CPU, thanks to Dan Barlow
* Martin Atzmueller ported Tim Moore's marvellous CMU CL DISASSEMBLE
  patch, so that DISASSEMBLE output is much nicer.
* The code in the SB-PROFILE package now seems reasonably stable.
  I still haven't decided what the final interface should look like
  (I'd like PROFILE to interact cleanly with TRACE, since both
  facilities use function encapsulation) but if you have a need
  for profiling now, you can probably use it successfully with
  the current CMU-CL-style interface.
* Pathnames and *DEFAULT-DIRECTORY-DEFAULTS* are much more
  ANSI-compliant, thanks to various fixes and tests from Dan Barlow.
  Also, at Dan Barlow's suggestion, TRUENAME on a dangling symbolic
  link now returns the dangling link itself, and for similar
  reasons, TRUENAME on a cyclic symbolic link returns the cyclic
  link itself. (In these cases the old code signalled an error and
  looped endlessly, respectively.) Thus, DIRECTORY now works even
  in the presence of dangling and cyclic symbolic links.
* Compiler trace output (the :TRACE-FILE option to COMPILE-FILE)
  is now a supported extension again, since the consensus on
  sbcl-devel was that it can be useful for ordinary development
  work, not just for debugging SBCL itself.
* The default for SB-EXT:*DERIVE-FUNCTION-TYPES* has changed to
  NIL, i.e. ANSI behavior, i.e. the compiler now recognizes
  that currently-defined functions might be redefined later with 
  different return types. 
* Hash tables can be printed readably, as inspired by CMU CL code
  of Eric Marsden and SBCL code of Martin Atzmueller.
* better error handling in CLOS method combination, thanks to 
  Martin Atzmueller porting Pierre Mai's CMU CL patches
* more overflow fixes for >16Mbyte I/O buffers
* A bug in READ has been fixed, so that now a single Ctrl-D
  character suffices to cause end-of-file on character streams.
  In particular, now you only need one Ctrl-D at the command
  line (not two) to exit SBCL.
* fixed bug 26: ARRAY-DISPLACEMENT now returns (VALUES NIL 0) for 
  undisplaced arrays.
* fixed bug 107 (reported as a CMU CL bug by Erik Naggum on 
  comp.lang.lisp 2001-06-11): (WRITE #*101 :RADIX T :BASE 36) now
  does the right thing.
* The implementation of some type tests, especially for CONDITION
  types, is now tidier and maybe faster, due to CMU CL code
  originally by Douglas Crosher, ported by Martin Atzmueller.
* Some math functions have been fixed, and there are new
  optimizers for deriving the types of COERCE and ARRAY-ELEMENT-TYPE,
  thanks to Raymond Toy's work on CMU CL, ported by Martin Atzmueller.
* (There are also some new optimizers in contrib/*-extras.lisp. Those
  aren't built into sbcl-0.6.13, but are a sneak preview of what's
  likely to be built into sbcl-0.7.0.)
* A bug in COPY-READTABLE was fixed. (Joao Cachopo's patch to CMU
  CL, ported to SBCL by Martin Atzmueller)
* DESCRIBE now gives more information in some cases. (Pierre Mai's
  patch to CMU CL, ported to SBCL by Martin Atzmueller)
* Martin Atzmueller and Bill Newman fixed some bugs in INSPECT.
* There's a new slam.sh hack to shorten the edit/compile/debug
  cycle for low-level changes to SBCL itself, and a new
  :SB-AFTER-XC-CORE target feature to control the generation of
  the after-xc.core file needed by slam.sh.
* minor incompatible change: The ENTRY-POINTS &KEY argument to 
  COMPILE-FILE is no longer supported, so that now every function
  gets an entry point, so that block compilation looks a little
  more like the plain vanilla ANSI section 3.2.2.3 scheme.
* minor incompatible change: SB-EXT:GET-BYTES-CONSED now
  returns the number of bytes consed since the system started,
  rather than the number consed since the first time the function
  was called. (The new definition parallels ANSI functions like
  CL:GET-INTERNAL-RUN-TIME.)
* minor incompatible change: The old CMU-CL-style DIRECTORY options,
  i.e. :ALL, :FOLLOW-LINKS, and :CHECK-FOR-SUBDIRS, are no longer
  supported. Now DIRECTORY always does the abstract Common-Lisp-y
  thing, i.e. :ALL T :FOLLOW-LINKS T :CHECK-FOR-SUBDIRS T.
* Fasl file version numbers are now independent of the target CPU,
  since historically most system changes which required version
  number changes have affected all CPUs equally. Similarly, 
  the byte fasl file version is now equal to the ordinary
  fasl file version.

changes in sbcl-0.7.0 relative to sbcl-0.6.13:
* There are new compiler optimizations for various functions: FIND,
  POSITION, FIND-IF, POSITION-IF, FILL, COERCE, TRUNCATE, FLOOR, and
  CEILING. Mostly these should be transparent, but there's one 
  potentially-annoying problem (bug 117): when the compiler inline
  expands the FIND/POSITION family of functions and does type
  analysis on the result, it can find control paths which have 
  type mismatches, and when it can't prove that they're not taken,
  it will issue WARNINGs about the type mismatches. It's not clear
  how to make the compiler smart enough to fix this in general, but
  a workaround is given in the entry for 117 in the BUGS file.
* The doc/cmucl/ directory, containing old CMU CL documentation,
  is no longer part of the base system. The files which used to 
  be in the doc/cmucl/ directory are now available as
    <ftp://sbcl.sourceforge.net/pub/sbcl/cmucl-docs.tar.bz2>.
* The default value of *BYTES-CONSED-BETWEEN-GCS* has been 
  doubled, to 4 million. (If your application spends a lot of time
  GCing and you have a lot of RAM, you might want to experiment with
  increasing it even more.)
?? The system's handling of top-level forms and EVAL-WHEN is now
  more ANSI-compliant, fixing bugs
    ?? IR1-3 and
    ?? IR1-3a.
  It's also done by much newer code, so there might be some new bugs,
  but hopefully if so they'll be less fundamental and more fixable.
* PPRINT-LOGICAL-BLOCK now copies the *PRINT-LINES* value on entry
  and uses that copy, rather than the current dynamic value, when
  it's trying to decide whether to truncate output . Thus e.g.
     (let ((*print-lines* 50))
       (pprint-logical-block (stream nil)
         (dotimes (i 10)
           (let ((*print-lines* 8))
             (print (aref possiblybigthings i) stream)))))
  should truncate the logical block only at 50 lines, instead of 
  often truncating it at 8 lines.
?? lots of tidying up internally: renaming things so that names are
  more systematic and consistent, converting C macros to inline
  functions, systematizing indentation
* The fasl file version number changed again, for any number of
  good reasons.

planned incompatible changes in 0.7.x:
* The debugger prompt sequence now goes "5]", "5[2]", "5[3]", etc.
  as you get deeper into recursive calls to the debugger command loop,
  instead of the old "5]", "5]]", "5]]]" sequence. (I was motivated
  to do this when squabbles between ILISP and SBCL left me
  very deeply nested in the debugger.)
* The fasl file extension may change, perhaps to ".fasl".
* The default output representation for unprintable ASCII characters 
  which, unlike e.g. #\Newline, don't have names defined in the 
  ANSI Common Lisp standard, may change to their ASCII symbolic
  names: #\Nul, #\Soh, #\Stx, etc.
* INTERNAL-TIME-UNITS-PER-SECOND might increase, e.g. to 1000.
* FASL file extensions change to ".fasl", instead of the various
  CPU-dependent values (".x86f", ".axpf", etc.) inherited from CMU CL.
* MAYBE-INLINE will probably go away at some point, maybe 0.7.x,
  maybe later, in favor of the ANSI-recommended idiom for making
  a function optionally inline.
* When the profiling interface settles down, maybe in 0.7.x, maybe
  later, it might impact TRACE. They both encapsulate functions, and
  it's not clear yet how e.g. UNPROFILE will interact with TRACE
  and UNTRACE. (This shouldn't matter, though, unless you are
  using profiling. If you never profile anything, TRACE should
  continue to behave as before.)
* The BYTE-COMPILE &KEY argument for COMPILE-FILE is deprecated,
  since this behavior can be controlled by (DECLAIM (OPTIMIZE (SPEED 0))).
  ("An ounce of orthogonality is worth a pound of features.")