Please send Guile bug reports to bug-guile@gnu.org.
\f
+Changes since Guile 1.4:
+
+* Changes to the distribution
+
+** New modules (oop goops) etc
+
+The new modules
+
+ (oop goops)
+ (oop goops describe)
+ (oop goops save)
+ (oop goops active-slot)
+ (oop goops composite-slot)
+
+plus some GOOPS utility modules have been added.
+
+* Changes to the stand-alone interpreter
+
+** GOOPS has been merged into Guile
+
+The Guile Object Oriented Programming System has been integrated into
+Guile.
+
+Type
+
+ (use-modules (oop goops))
+
+access GOOPS bindings.
+
+We're now ready to try some basic GOOPS functionality.
+
+Generic functions
+
+ (define-method (+ (x <string>) (y <string>))
+ (string-append x y))
+
+ (+ 1 2) --> 3
+ (+ "abc" "de") --> "abcde"
+
+User-defined types
+
+ (define-class <2D-vector> ()
+ (x #:init-value 0 #:accessor x-component #:init-keyword #:x)
+ (y #:init-value 0 #:accessor y-component #:init-keyword #:y))
+
+ (define-method write ((obj <2D-vector>) port)
+ (display (format #f "<~S, ~S>" (x-component obj) (y-component obj))
+ port))
+
+ (define v (make <2D-vector> #:x 3 #:y 4))
+ v --> <3, 4>
+
+ (define-method + ((x <2D-vector>) (y <2D-vector>))
+ (make <2D-vector>
+ #:x (+ (x-component x) (x-component y))
+ #:y (+ (y-component x) (y-component y))))
+
+ (+ v v) --> <6, 8>
+
+Asking for the type of an object
+
+ (class-of v) --> #<<class> <2D-vector> 40241ac0>
+ <2D-vector> --> #<<class> <2D-vector> 40241ac0>
+ (class-of 1) --> #<<class> <integer> 401b2a98>
+ <integer> --> #<<class> <integer> 401b2a98>
+
+ (is-a? v <2D-vector>) --> #t
+
+See further in the GOOPS tutorial available in the guile-doc
+distribution in info (goops.info) and texinfo formats.
+
+** It's now possible to create modules with controlled environments
+
+Example:
+
+(use-modules (ice-9 safe))
+(define m (make-safe-module))
+;;; m will now be a module containing only a safe subset of R5RS
+(eval-in-module '(+ 1 2) m) --> 3
+(eval-in-module 'load m) --> ERROR: Unbound variable: load
+
+* Changes to Scheme functions and syntax
+
+** New function `make-object-property'
+
+This function returns a new `procedure with setter' P that can be used
+to attach a property to objects. When calling P as
+
+ (set! (P obj) val)
+
+where `obj' is any kind of object, it attaches `val' to `obj' in such
+a way that it can be retrieved by calling P as
+
+ (P obj)
+
+This function will replace procedure properties, symbol properties and
+source properties eventually.
+
+** Module (ice-9 optargs) now uses keywords instead of `#&'.
+
+Instead of #&optional, #&key, etc you should now use #:optional,
+#:key, etc. Since #:optional is a keyword, you can write it as just
+:optional when (read-set! keywords 'prefix) is active.
+
+The old reader syntax `#&' is still supported, but deprecated. It
+will be removed in the next release.
+
+** Backward incompatible change: eval EXP ENVIRONMENT-SPECIFIER
+
+`eval' is now R5RS, that is it takes two arguments.
+The second argument is an environment specifier, i.e. either
+
+ (scheme-report-environment 5)
+ (null-environment 5)
+ (interaction-environment)
+
+or
+
+ any module.
+
+** New define-module option: pure
+
+Tells the module system not to include any bindings from the root
+module.
+
+Example:
+
+(define-module (totally-empty-module)
+ :pure)
+
+** New define-module option: export NAME1 ...
+
+Export names NAME1 ...
+
+This option is required if you want to be able to export bindings from
+a module which doesn't import one of `define-public' or `export'.
+
+Example:
+
+(define-module (foo)
+ :pure
+ :use-module (ice-9 r5rs)
+ :export (bar))
+
+;;; Note that we're pure R5RS below this point!
+
+(define (bar)
+ ...)
+
+** Deprecated: scm_make_shared_substring
+
+Explicit shared substrings will disappear from Guile.
+
+Instead, "normal" strings will be implemented using sharing
+internally, combined with a copy-on-write strategy.
+
+** Deprecated: scm_read_only_string_p
+
+The concept of read-only strings will disappear in next release of
+Guile.
+
+** Deprecated: scm_sloppy_memq, scm_sloppy_memv, scm_sloppy_member
+
+Instead, use scm_memq, scm_memv, scm_member.
+
+** New function: port? X
+
+Returns a boolean indicating whether X is a port. Equivalent to
+`(or (input-port? X) (output-port? X))'.
+
+** New function: port-for-each proc
+
+Apply PROC to each port in the Guile port table in turn. The
+return value is unspecified.
+
+** New function: dup2 oldfd newfd
+
+A simple wrapper for the `dup2' system call. Copies the file
+descriptor OLDFD to descriptor number NEWFD, replacing the
+previous meaning of NEWFD. Both OLDFD and NEWFD must be integers.
+Unlike for dup->fdes or primitive-move->fdes, no attempt is made
+to move away ports which are using NEWFD\n". The return value is
+unspecified.
+
+** New function: close-fdes fd
+
+A simple wrapper for the `close' system call. Close file
+descriptor FD, which must be an integer. Unlike close (*note
+close: Ports and File Descriptors.), the file descriptor will be
+closed even if a port is using it. The return value is
+unspecified.
+
+** Deprecated: close-all-ports-except. This was intended for closing
+ports in a child process after a fork, but it has the undesirable side
+effect of flushing buffers. port-for-each is more flexible.
+
+** The (ice-9 popen) module now attempts to set up file descriptors in
+the child process from the current Scheme ports, instead of using the
+current values of file descriptors 0, 1, and 2 in the parent process.
+
+* Changes to the gh_ interface
+
+* Changes to the scm_ interface
+
+** New function: scm_init_guile ()
+
+In contrast to scm_boot_guile, scm_init_guile will return normally
+after initializing Guile. It is not available on all systems, tho.
+
+** New functions: scm_primitive_make_property
+ scm_primitive_property_ref
+ scm_primitive_property_set_x
+ scm_primitive_property_del_x
+
+These functions implement a new way to deal with object properties.
+See libguile/properties.c for their documentation.
+
+** New function: scm_done_free (long size)
+
+This function is the inverse of scm_done_malloc. Use it to report the
+amount of smob memory you free. The previous method, which involved
+calling scm_done_malloc with negative argument, was somewhat
+unintuitive (and is still available, of course).
+
+** New global variable scm_gc_running_p introduced.
+
+Use this variable to find out if garbage collection is being executed. Up to
+now applications have used scm_gc_heap_lock to test if garbage collection was
+running, which also works because of the fact that up to know only the garbage
+collector has set this variable. But, this is an implementation detail that
+may change. Further, scm_gc_heap_lock is not set throughout gc, thus the use
+of this variable is (and has been) not fully safe anyway.
+
+** New macros: SCM_BITVECTOR_MAX_LENGTH, SCM_UVECTOR_MAX_LENGTH
+
+Use these instead of SCM_LENGTH_MAX.
+
+** New macros: SCM_CONTINUATION_LENGTH, SCM_CCLO_LENGTH, SCM_STACK_LENGTH,
+SCM_STRING_LENGTH, SCM_SYMBOL_LENGTH, SCM_UVECTOR_LENGTH,
+SCM_BITVECTOR_LENGTH, SCM_VECTOR_LENGTH.
+
+Use these instead of SCM_LENGTH.
+
+** New macros: SCM_SET_CONTINUATION_LENGTH, SCM_SET_STRING_LENGTH,
+SCM_SET_SYMBOL_LENGTH, SCM_SET_VECTOR_LENGTH, SCM_SET_UVECTOR_LENGTH,
+SCM_SET_BITVECTOR_LENGTH
+
+Use these instead of SCM_SETLENGTH
+
+** New macros: SCM_STRING_CHARS, SCM_SYMBOL_CHARS, SCM_CCLO_BASE,
+SCM_VECTOR_BASE, SCM_UVECTOR_BASE, SCM_BITVECTOR_BASE, SCM_COMPLEX_MEM,
+SCM_ARRAY_MEM
+
+Use these instead of SCM_CHARS, SCM_UCHARS, SCM_ROCHARS, SCM_ROUCHARS or
+SCM_VELTS.
+
+** New macros: SCM_SET_BIGNUM_BASE, SCM_SET_STRING_CHARS,
+SCM_SET_SYMBOL_CHARS, SCM_SET_UVECTOR_BASE, SCM_SET_BITVECTOR_BASE,
+SCM_SET_VECTOR_BASE
+
+Use these instead of SCM_SETCHARS.
+
+** New macro: SCM_BITVECTOR_P
+
+** New macro: SCM_STRING_COERCE_0TERMINATION_X
+
+Use instead of SCM_COERCE_SUBSTR.
+
+** Deprecated macros: SCM_OUTOFRANGE, SCM_NALLOC, SCM_HUP_SIGNAL,
+SCM_INT_SIGNAL, SCM_FPE_SIGNAL, SCM_BUS_SIGNAL, SCM_SEGV_SIGNAL,
+SCM_ALRM_SIGNAL, SCM_GC_SIGNAL, SCM_TICK_SIGNAL, SCM_SIG_ORD,
+SCM_ORD_SIG, SCM_NUM_SIGS, SCM_SYMBOL_SLOTS, SCM_SLOTS, SCM_SLOPPY_STRINGP,
+SCM_VALIDATE_STRINGORSUBSTR, SCM_FREEP, SCM_NFREEP, SCM_CHARS, SCM_UCHARS,
+SCM_VALIDATE_ROSTRING, SCM_VALIDATE_ROSTRING_COPY,
+SCM_VALIDATE_NULLORROSTRING_COPY, SCM_ROLENGTH, SCM_LENGTH, SCM_HUGE_LENGTH,
+SCM_SUBSTRP, SCM_SUBSTR_STR, SCM_SUBSTR_OFFSET, SCM_COERCE_SUBSTR,
+SCM_ROSTRINGP, SCM_RWSTRINGP, SCM_VALIDATE_RWSTRING, SCM_ROCHARS,
+SCM_ROUCHARS, SCM_SETLENGTH, SCM_SETCHARS, SCM_LENGTH_MAX
+
+Use SCM_ASSERT_RANGE or SCM_VALIDATE_XXX_RANGE instead of SCM_OUTOFRANGE.
+Use scm_memory_error instead of SCM_NALLOC.
+Use SCM_STRINGP instead of SCM_SLOPPY_STRINGP.
+Use SCM_VALIDATE_STRING instead of SCM_VALIDATE_STRINGORSUBSTR.
+Use SCM_FREE_CELL_P instead of SCM_FREEP/SCM_NFREEP
+Use a type specific accessor macro instead of SCM_CHARS/SCM_UCHARS.
+Use a type specific accessor instead of SCM(_|_RO|_HUGE_)LENGTH.
+Use SCM_VALIDATE_(SYMBOL|STRING) instead of SCM_VALIDATE_ROSTRING.
+Use SCM_STRING_COERCE_0TERMINATION_X instead of SCM_COERCE_SUBSTR.
+Use SCM_STRINGP or SCM_SYMBOLP instead of SCM_ROSTRINGP.
+Use SCM_STRINGP instead of SCM_RWSTRINGP.
+Use SCM_VALIDATE_STRING instead of SCM_VALIDATE_RWSTRING.
+Use SCM_STRING_CHARS instead of SCM_ROCHARS.
+Use SCM_STRING_UCHARS instead of SCM_ROUCHARS.
+Use a type specific setter macro instead of SCM_SETLENGTH.
+Use a type specific setter macro instead of SCM_SETCHARS.
+Use a type specific length macro instead of SCM_LENGTH_MAX.
+
+** Removed function: scm_struct_init
+
+** Deprecated function: scm_call_catching_errors
+
+Use scm_catch or scm_lazy_catch from throw.[ch] instead.
+
+** Deprecated function: scm_strhash
+
+Use scm_string_hash instead.
+
+** Deprecated function: scm_vector_set_length_x
+
+Instead, create a fresh vector of the desired size and copy the contents.
+
+** scm_gensym has changed prototype
+
+scm_gensym now only takes one argument.
+
+** New function: scm_gentemp (SCM prefix, SCM obarray)
+
+The builtin `gentemp' has now become a primitive.
+
+** Deprecated type tags: scm_tc7_ssymbol, scm_tc7_msymbol, scm_tcs_symbols,
+scm_tc7_lvector
+
+There is now only a single symbol type scm_tc7_symbol.
+The tag scm_tc7_lvector was not used anyway.
+
+\f
Changes since Guile 1.3.4:
* Changes to the distribution
These are likely to become separate modules some day.
-** Added new configure option --enable-debug-freelist
+** New configure option --enable-debug-freelist
This enables a debugging version of SCM_NEWCELL(), and also registers
an extra primitive, the setter `gc-set-debug-check-freelist!'.
slow down the interpreter dramatically, so the setter should be used to
turn on this extra processing only when necessary.
+** New configure option --enable-debug-malloc
+
+Include code for debugging of calls to scm_must_malloc/realloc/free.
+
+Checks that
+
+1. objects freed by scm_must_free has been mallocated by scm_must_malloc
+2. objects reallocated by scm_must_realloc has been allocated by
+ scm_must_malloc
+3. reallocated objects are reallocated with the same what string
+
+But, most importantly, it records the number of allocated objects of
+each kind. This is useful when searching for memory leaks.
+
+A Guile compiled with this option provides the primitive
+`malloc-stats' which returns an alist with pairs of kind and the
+number of objects of that kind.
+
+** All includes are now referenced relative to the root directory
+
+Since some users have had problems with mixups between Guile and
+system headers, we have decided to always refer to Guile headers via
+their parent directories. This essentially creates a "private name
+space" for Guile headers. This means that the compiler only is given
+-I options for the root build and root source directory.
+
+** Header files kw.h and genio.h have been removed.
+
+** The module (ice-9 getopt-gnu-style) has been removed.
+
+** New module (ice-9 documentation)
+
+Implements the interface to documentation strings associated with
+objects.
+
* Changes to the stand-alone interpreter
+** New command line option --debug
+
+Start Guile with debugging evaluator and backtraces enabled.
+
+This is useful when debugging your .guile init file or scripts.
+
+** New help facility
+
+Usage: (help NAME) gives documentation about objects named NAME (a symbol)
+ (help REGEXP) ditto for objects with names matching REGEXP (a string)
+ (help ,EXPR) gives documentation for object returned by EXPR
+ (help) gives this text
+
+`help' searches among bindings exported from loaded modules, while
+`apropos' searches among bindings visible from the "current" module.
+
+Examples: (help help)
+ (help cons)
+ (help "output-string")
+
+** `help' and `apropos' now prints full module names
+
** Dynamic linking now uses libltdl from the libtool package.
The old system dependent code for doing dynamic linking has been
to specify a name like "libfoo", without any directories and
extensions.
+** Guile COOP threads are now compatible with LinuxThreads
+
+Previously, COOP threading wasn't possible in applications linked with
+Linux POSIX threads due to their use of the stack pointer to find the
+thread context. This has now been fixed with a workaround which uses
+the pthreads to allocate the stack.
+
** New primitives: `pkgdata-dir', `site-dir', `library-dir'
** Positions of erring expression in scripts
(The first options enables the debugging evaluator.
The second enables backtraces.)
+** Part of module system symbol lookup now implemented in C
+
+The eval closure of most modules is now implemented in C. Since this
+was one of the bottlenecks for loading speed, Guile now loads code
+substantially faster than before.
+
** Attempting to get the value of an unbound variable now produces
an exception with a key of 'unbound-variable instead of 'misc-error.
** The initial default output port is now unbuffered if it's using a
tty device. Previously in this situation it was line-buffered.
+** gc-thunk is deprecated
+
+gc-thunk will be removed in next release of Guile. It has been
+replaced by after-gc-hook.
+
+** New hook: after-gc-hook
+
+after-gc-hook takes over the role of gc-thunk. This hook is run at
+the first SCM_TICK after a GC. (Thus, the code is run at the same
+point during evaluation as signal handlers.)
+
+Note that this hook should be used only for diagnostic and debugging
+purposes. It is not certain that it will continue to be well-defined
+when this hook is run in the future.
+
+C programmers: Note the new C level hooks scm_before_gc_c_hook,
+scm_before_sweep_c_hook, scm_after_gc_c_hook.
+
+** Improvements to garbage collector
+
+Guile 1.4 has a new policy for triggering heap allocation and
+determining the sizes of heap segments. It fixes a number of problems
+in the old GC.
+
+1. The new policy can handle two separate pools of cells
+ (2-word/4-word) better. (The old policy would run wild, allocating
+ more and more memory for certain programs.)
+
+2. The old code would sometimes allocate far too much heap so that the
+ Guile process became gigantic. The new code avoids this.
+
+3. The old code would sometimes allocate too little so that few cells
+ were freed at GC so that, in turn, too much time was spent in GC.
+
+4. The old code would often trigger heap allocation several times in a
+ row. (The new scheme predicts how large the segments needs to be
+ in order not to need further allocation.)
+
+All in all, the new GC policy will make larger applications more
+efficient.
+
+The new GC scheme also is prepared for POSIX threading. Threads can
+allocate private pools of cells ("clusters") with just a single
+function call. Allocation of single cells from such a cluster can
+then proceed without any need of inter-thread synchronization.
+
+** New environment variables controlling GC parameters
+
+GUILE_MAX_SEGMENT_SIZE Maximal segment size
+ (default = 2097000)
+
+Allocation of 2-word cell heaps:
+
+GUILE_INIT_SEGMENT_SIZE_1 Size of initial heap segment in bytes
+ (default = 360000)
+
+GUILE_MIN_YIELD_1 Minimum number of freed cells at each
+ GC in percent of total heap size
+ (default = 40)
+
+Allocation of 4-word cell heaps
+(used for real numbers and misc other objects):
+
+GUILE_INIT_SEGMENT_SIZE_2, GUILE_MIN_YIELD_2
+
+(See entry "Way for application to customize GC parameters" under
+ section "Changes to the scm_ interface" below.)
+
+** Guile now implements reals using 4-word cells
+
+This speeds up computation with reals. (They were earlier allocated
+with `malloc'.) There is still some room for optimizations, however.
+
+** Some further steps toward POSIX thread support have been taken
+
+*** Guile's critical sections (SCM_DEFER/ALLOW_INTS)
+don't have much effect any longer, and many of them will be removed in
+next release.
+
+*** Signals
+are only handled at the top of the evaluator loop, immediately after
+I/O, and in scm_equalp.
+
+*** The GC can allocate thread private pools of pairs.
+
* Changes to Scheme functions and syntax
+** close-input-port and close-output-port are now R5RS
+
+These procedures have been turned into primitives and have R5RS behaviour.
+
** New procedure: simple-format PORT MESSAGE ARG1 ...
(ice-9 boot) makes `format' an alias for `simple-format' until possibly
** New procedure: port-closed? PORT
Returns #t if PORT is closed or #f if it is open.
+** Deprecated: list*
+
+The list* functionality is now provided by cons* (SRFI-1 compliant)
+
+** New procedure: cons* ARG1 ARG2 ... ARGn
+
+Like `list', but the last arg provides the tail of the constructed list,
+returning (cons ARG1 (cons ARG2 (cons ... ARGn))).
+
+Requires at least one argument. If given one argument, that argument
+is returned as result.
+
+This function is called `list*' in some other Schemes and in Common LISP.
+
+** Removed deprecated: serial-map, serial-array-copy!, serial-array-map!
+
+** New procedure: object-documentation OBJECT
+
+Returns the documentation string associated with OBJECT. The
+procedure uses a caching mechanism so that subsequent lookups are
+faster.
+
+Exported by (ice-9 documentation).
+
+** module-name now returns full names of modules
+
+Previously, only the last part of the name was returned (`session' for
+`(ice-9 session)'). Ex: `(ice-9 session)'.
+
+* Changes to the gh_ interface
+
+** Deprecated: gh_int2scmb
+
+Use gh_bool2scm instead.
+
* Changes to the scm_ interface
** Guile primitives now carry docstrings!
Thanks to Greg Badros!
-** Guile primitives are defined in a new way: GUILE_PROC/GUILE_PROC1
+** Guile primitives are defined in a new way: SCM_DEFINE/SCM_DEFINE1/SCM_PROC
-Now Guile primitives are defined using the GUILE_PROC/GUILE_PROC1 macros
-and must contain a docstring that is extracted into foo.doc using a new
+Now Guile primitives are defined using the SCM_DEFINE/SCM_DEFINE1/SCM_PROC
+macros and must contain a docstring that is extracted into foo.doc using a new
guile-doc-snarf script (that uses guile-doc-snarf.awk).
+However, a major overhaul of these macros is scheduled for the next release of
+guile.
+
** Guile primitives use a new technique for validation of arguments
SCM_VALIDATE_* macros are defined to ease the redundancy and improve
** All (nearly?) K&R prototypes for functions replaced with ANSI C equivalents.
+** New macros: SCM_PACK, SCM_UNPACK
+
+Compose/decompose an SCM value.
+
+The SCM type is now treated as an abstract data type and may be defined as a
+long, a void* or as a struct, depending on the architecture and compile time
+options. This makes it easier to find several types of bugs, for example when
+SCM values are treated as integers without conversion. Values of the SCM type
+should be treated as "atomic" values. These macros are used when
+composing/decomposing an SCM value, either because you want to access
+individual bits, or because you want to treat it as an integer value.
+
+E.g., in order to set bit 7 in an SCM value x, use the expression
+
+ SCM_PACK (SCM_UNPACK (x) | 0x80)
+
+** The name property of hooks is deprecated.
+Thus, the use of SCM_HOOK_NAME and scm_make_hook_with_name is deprecated.
+
+You can emulate this feature by using object properties.
+
+** Deprecated macros: SCM_INPORTP, SCM_OUTPORTP, SCM_CRDY, SCM_ICHRP,
+SCM_ICHR, SCM_MAKICHR, SCM_SETJMPBUF, SCM_NSTRINGP, SCM_NRWSTRINGP,
+SCM_NVECTORP
+
+These macros will be removed in a future release of Guile.
+
+** The following types, functions and macros from numbers.h are deprecated:
+scm_dblproc, SCM_UNEGFIXABLE, SCM_FLOBUFLEN, SCM_INEXP, SCM_CPLXP, SCM_REAL,
+SCM_IMAG, SCM_REALPART, scm_makdbl, SCM_SINGP, SCM_NUM2DBL, SCM_NO_BIGDIG
+
+Further, it is recommended not to rely on implementation details for guile's
+current implementation of bignums. It is planned to replace this
+implementation with gmp in the future.
+
** Port internals: the rw_random variable in the scm_port structure
must be set to non-zero in any random access port. In recent Guile
releases it was only set for bidirectional random-access ports.
chars requires further hacking that depends on the characteristics
of the ptob.
+** Deprecated functions: scm_fseek, scm_tag
+
+These functions are no longer used and will be removed in a future version.
+
** The scm_sysmissing procedure is no longer used in libguile.
Unless it turns out to be unexpectedly useful to somebody, it will be
removed in a future version.
currently executing threads, nor call the destructor function
associated with the key.
+** New function: scm_c_hook_init (scm_c_hook_t *HOOK, void *HOOK_DATA, scm_c_hook_type_t TYPE)
+
+Initialize a C level hook HOOK with associated HOOK_DATA and type
+TYPE. (See scm_c_hook_run ().)
+
+** New function: scm_c_hook_add (scm_c_hook_t *HOOK, scm_c_hook_function_t FUNC, void *FUNC_DATA, int APPENDP)
+
+Add hook function FUNC with associated FUNC_DATA to HOOK. If APPENDP
+is true, add it last, otherwise first. The same FUNC can be added
+multiple times if FUNC_DATA differ and vice versa.
+
+** New function: scm_c_hook_remove (scm_c_hook_t *HOOK, scm_c_hook_function_t FUNC, void *FUNC_DATA)
+
+Remove hook function FUNC with associated FUNC_DATA from HOOK. A
+function is only removed if both FUNC and FUNC_DATA matches.
+
+** New function: void *scm_c_hook_run (scm_c_hook_t *HOOK, void *DATA)
+
+Run hook HOOK passing DATA to the hook functions.
+
+If TYPE is SCM_C_HOOK_NORMAL, all hook functions are run. The value
+returned is undefined.
+
+If TYPE is SCM_C_HOOK_OR, hook functions are run until a function
+returns a non-NULL value. This value is returned as the result of
+scm_c_hook_run. If all functions return NULL, NULL is returned.
+
+If TYPE is SCM_C_HOOK_AND, hook functions are run until a function
+returns a NULL value, and NULL is returned. If all functions returns
+a non-NULL value, the last value is returned.
+
+** New C level GC hooks
+
+Five new C level hooks has been added to the garbage collector.
+
+ scm_before_gc_c_hook
+ scm_after_gc_c_hook
+
+are run before locking and after unlocking the heap. The system is
+thus in a mode where evaluation can take place. (Except that
+scm_before_gc_c_hook must not allocate new cells.)
+
+ scm_before_mark_c_hook
+ scm_before_sweep_c_hook
+ scm_after_sweep_c_hook
+
+are run when the heap is locked. These are intended for extension of
+the GC in a modular fashion. Examples are the weaks and guardians
+modules.
+
+** Way for application to customize GC parameters
+
+The application can set up other default values for the GC heap
+allocation parameters
+
+ GUILE_INIT_HEAP_SIZE_1, GUILE_MIN_YIELD_1,
+ GUILE_INIT_HEAP_SIZE_2, GUILE_MIN_YIELD_2,
+ GUILE_MAX_SEGMENT_SIZE,
+
+by setting
+
+ scm_default_init_heap_size_1, scm_default_min_yield_1,
+ scm_default_init_heap_size_2, scm_default_min_yield_2,
+ scm_default_max_segment_size
+
+respectively before callong scm_boot_guile.
+
+(See entry "New environment variables ..." in section
+"Changes to the stand-alone interpreter" above.)
+
+** scm_protect_object/scm_unprotect_object now nest
+
+This means that you can call scm_protect_object multiple times on an
+object and count on the object being protected until
+scm_unprotect_object has been call the same number of times.
+
+The functions also have better time complexity.
+
+Still, it is usually possible to structure the application in a way
+that you don't need to use these functions. For example, if you use a
+protected standard Guile list to keep track of live objects rather
+than some custom data type, objects will die a natural death when they
+are no longer needed.
+
+** Deprecated type tags: scm_tc16_flo, scm_tc_flo, scm_tc_dblr, scm_tc_dblc
+
+Guile does not provide the float representation for inexact real numbers any
+more. Now, only doubles are used to represent inexact real numbers. Further,
+the tag names scm_tc_dblr and scm_tc_dblc have been changed to scm_tc16_real
+and scm_tc16_complex, respectively.
+
+** Removed deprecated type scm_smobfuns
+
+** Removed deprecated function scm_newsmob
+
+** Warning: scm_make_smob_type_mfpe might become deprecated in a future release
+
+There is an ongoing discussion among the developers whether to
+deprecate `scm_make_smob_type_mfpe' or not. Please use the current
+standard interface (scm_make_smob_type, scm_set_smob_XXX) in new code
+until this issue has been settled.
+
+** Removed deprecated type tag scm_tc16_kw
+
+** Added type tag scm_tc16_keyword
+
+(This was introduced already in release 1.3.4 but was not documented
+ until now.)
+
+** gdb_print now prints "*** Guile not initialized ***" until Guile initialized
+
* Changes to system call interfaces:
** The "select" procedure now tests port buffers for the ability to
** New constants: vtable-index-layout, vtable-index-vtable, vtable-index-printer
-** There is now a fourth (optional) argument to make-vtable-vtable and
- make-struct when constructing new types (vtables). This argument
- initializes field vtable-index-printer of the vtable.
+** There is now a third optional argument to make-vtable-vtable
+ (and fourth to make-struct) when constructing new types (vtables).
+ This argument initializes field vtable-index-printer of the vtable.
** The detection of circular references has been extended to structs.
That is, a structure that -- in the process of being printed -- prints