1 Guile NEWS --- history of user-visible changes. -*- text -*-
2 Copyright (C) 1996, 1997 Free Software Foundation, Inc.
3 See the end for copying conditions.
5 Please send Guile bug reports to bug-guile@gnu.org.
7 Changes since Guile 1.2:
9 * Changes to the distribution
11 ** We renamed the SCHEME_LOAD_PATH environment variable to GUILE_LOAD_PATH.
12 To avoid conflicts, programs should name environment variables after
13 themselves, except when there's a common practice establishing some
16 For now, Guile supports both GUILE_LOAD_PATH and SCHEME_LOAD_PATH,
17 giving the former precedence, and printing a warning message if the
18 latter is set. Guile 1.4 will not recognize SCHEME_LOAD_PATH at all.
20 ** The header files related to multi-byte characters have been removed.
21 They were: libguile/extchrs.h and libguile/mbstrings.h. Any C code
22 which referred to these explicitly will probably need to be rewritten,
23 since the support for the variant string types has been removed; see
26 ** The header files append.h and sequences.h have been removed. These
27 files implemented non-R4RS operations which would encourage
28 non-portable programming style and less easy-to-read code.
30 * Changes to the stand-alone interpreter
32 ** New procedures have been added to implement a "batch mode":
34 *** Function: batch-mode?
36 Returns a boolean indicating whether the interpreter is in batch
39 *** Function: set-batch-mode?! ARG
41 If ARG is true, switches the interpreter to batch mode. The `#f'
42 case has not been implemented.
44 ** Guile now provides full command-line editing, when run interactively.
45 To use this feature, you must have the readline library installed.
46 The Guile build process will notice it, and automatically include
49 The readline library is available via anonymous FTP from any GNU
50 mirror site; the canonical location is "ftp://prep.ai.mit.edu/pub/gnu".
52 ** the-last-stack is now a fluid.
54 * Changes to the procedure for linking libguile with your programs
56 ** You can now use the 'build-guile' utility to link against Guile.
58 Guile now includes a command-line utility called 'build-guile', which
59 writes to its standard output a list of flags which you must pass to
60 the linker to link against the Guile library. The flags include
61 '-lguile' itself, and any other libraries the Guile library depends
64 For example, here is a Makefile rule that builds a program named 'foo'
65 from the object files ${FOO_OBJECTS}, and links them against Guile:
68 ${CC} ${CFLAGS} ${FOO_OBJECTS} `build-guile link` -o foo
70 Previous Guile releases recommended that you use autoconf to detect
71 which of a predefined set of libraries were present on your system.
72 It is more robust to use build-guile, since it records exactly which
73 libraries the installed Guile library requires.
76 * Changes to Scheme functions and syntax
78 ** Multi-byte strings have been removed, as have multi-byte and wide
79 ports. We felt that these were the wrong approach to
80 internationalization support.
82 ** New function: readline [PROMPT]
83 Read a line from the terminal, and allow the user to edit it,
84 prompting with PROMPT. READLINE provides a large set of Emacs-like
85 editing commands, lets the user recall previously typed lines, and
86 works on almost every kind of terminal, including dumb terminals.
88 READLINE assumes that the cursor is at the beginning of the line when
89 it is invoked. Thus, you can't print a prompt yourself, and then call
90 READLINE; you need to package up your prompt as a string, pass it to
91 the function, and let READLINE print the prompt itself. This is
92 because READLINE needs to know the prompt's screen width.
94 For Guile to provide this function, you must have the readline library
95 installed on your system.
97 See also ADD-HISTORY function.
99 ** New function: add-history STRING
100 Add STRING as the most recent line in the history used by the READLINE
101 command. READLINE does not add lines to the history itself; you must
102 call ADD-HISTORY to make previous input available to the user.
104 ** New module (ice-9 getopt-gnu-style): Parse command-line arguments.
106 This module provides some simple argument parsing. It exports one
109 Function: getopt-gnu-style ARG-LS
110 Parse a list of program arguments into an alist of option
113 Each item in the list of program arguments is examined to see if
114 it meets the syntax of a GNU long-named option. An argument like
115 `--MUMBLE' produces an element of the form (MUMBLE . #t) in the
116 returned alist, where MUMBLE is a keyword object with the same
117 name as the argument. An argument like `--MUMBLE=FROB' produces
118 an element of the form (MUMBLE . FROB), where FROB is a string.
120 As a special case, the returned alist also contains a pair whose
121 car is the symbol `rest'. The cdr of this pair is a list
122 containing all the items in the argument list that are not options
123 of the form mentioned above.
125 The argument `--' is treated specially: all items in the argument
126 list appearing after such an argument are not examined, and are
127 returned in the special `rest' list.
129 This function does not parse normal single-character switches.
130 You will need to parse them out of the `rest' list yourself.
132 ** macro-eval! is removed. Use local-eval instead.
134 ** Some magic has been added to the printer to better handle user
135 written printing routines (like record printers, closure printers).
137 The problem is that these user written routines must have access to
138 the current `print-state' to be able to handle fancy things like
139 detection of circular references. These print-states have to be
140 passed to the builtin printing routines (display, write, etc) to
141 properly continue the print chain.
143 We didn't want to change all existing print code so that it
144 explicitely passes thru a print state in addition to a port. Instead,
145 we extented the possible values that the builtin printing routines
146 accept as a `port'. In addition to a normal port, they now also take
147 a pair of a normal port and a print-state. Printing will go to the
148 port and the print-state will be used to control the detection of
149 circular references, etc. If the builtin function does not care for a
150 print-state, it is simply ignored.
152 User written callbacks are now called with such a pair as their
153 `port', but because every function now accepts this pair as a PORT
154 argument, you don't have to worry about that. In fact, it is probably
155 safest to not check for these pairs.
157 However, it is sometimes necessary to continue a print chain on a
158 different port, for example to get a intermediate string
159 representation of the printed value, mangle that string somehow, and
160 then to finally print the mangled string. Use the new function
162 inherit-print-state OLD-PORT NEW-PORT
164 for this. It constructs a new `port' that prints to NEW-PORT but
165 inherits the print-state of OLD-PORT.
167 ** struct-vtable-offset renamed to vtable-offset-user
169 ** New constants: vtable-index-layout, vtable-index-vtable, vtable-index-printer
171 ** There is now a fourth (optional) argument to make-vtable-vtable and
172 make-struct when constructing new types (vtables). This argument
173 initializes field vtable-index-printer of the vtable.
175 ** The detection of circular references has been extended to structs.
176 That is, a structure that -- in the process of being printed -- prints
177 itself does not lead to infinite recursion.
179 ** There is now some basic support for fluids. Please read
180 "libguile/fluid.h" to find out more. It is accessible from Scheme with
181 the following functions and macros:
185 Create a new fluid object. Fluids are not special variables or
186 some other extension to the semantics of Scheme, but rather
187 ordinary Scheme objects. You can store them into variables (that
188 are still lexically scoped, of course) or into any other place you
189 like. Every fluid has a initial value of `#f'.
193 Test whether OBJ is a fluid.
195 Function: fluid-ref FLUID
196 Function: fluid-set! FLUID VAL
198 Access/modify the fluid FLUID. Modifications are only visible
199 within the current dynamic root (that includes threads).
201 Function: with-fluids* FLUIDS VALUES THUNK
203 FLUIDS is a list of fluids and VALUES a corresponding list of
204 values for these fluids. Before THUNK gets called the values are
205 installed in the fluids and the old values of the fluids are
206 saved in the VALUES list. When the flow of control leaves THUNK
207 or reenters it, the values get swapped again. You might think of
208 this as a `safe-fluid-excursion'. Note that the VALUES list is
209 modified by `with-fluids*'.
211 Macro: with-fluids ((FLUID VALUE) ...) FORM ...
213 The same as `with-fluids*' but with a different syntax. It looks
214 just like `let', but both FLUID and VALUE are evaluated. Remember,
215 fluids are not special variables but ordinary objects. FLUID
216 should evaluate to a fluid.
218 ** Changes to system call interfaces:
220 *** close-port, close-input-port and close-output-port now return a
221 boolean instead of an `unspecified' object. #t means that the port
222 was successfully closed, while #f means it was already closed. It is
223 also now possible for these procedures to raise an exception if an
224 error occurs (some errors from write can be delayed until close.)
226 *** the first argument to chmod, fcntl, ftell and fseek can now be a
229 *** the third argument to fcntl is now optional.
231 *** the first argument to chown can now be a file descriptor or a port.
233 *** the argument to stat can now be a port.
235 *** The following new procedures have been added (most use scsh
238 *** procedure: close PORT/FD
239 Similar to close-port (*note close-port: Closing Ports.), but also
240 works on file descriptors. A side effect of closing a file
241 descriptor is that any ports using that file descriptor are moved
242 to a different file descriptor and have their revealed counts set
245 *** procedure: port->fdes PORT
246 Returns the integer file descriptor underlying PORT. As a side
247 effect the revealed count of PORT is incremented.
249 *** procedure: fdes->ports FDES
250 Returns a list of existing ports which have FDES as an underlying
251 file descriptor, without changing their revealed counts.
253 *** procedure: fdes->inport FDES
254 Returns an existing input port which has FDES as its underlying
255 file descriptor, if one exists, and increments its revealed count.
256 Otherwise, returns a new input port with a revealed count of 1.
258 *** procedure: fdes->outport FDES
259 Returns an existing output port which has FDES as its underlying
260 file descriptor, if one exists, and increments its revealed count.
261 Otherwise, returns a new output port with a revealed count of 1.
263 The next group of procedures perform a `dup2' system call, if NEWFD
264 (an integer) is supplied, otherwise a `dup'. The file descriptor to be
265 duplicated can be supplied as an integer or contained in a port. The
266 type of value returned varies depending on which procedure is used.
268 All procedures also have the side effect when performing `dup2' that
269 any ports using NEWFD are moved to a different file descriptor and have
270 their revealed counts set to zero.
272 *** procedure: dup->fdes PORT/FD [NEWFD]
273 Returns an integer file descriptor.
275 *** procedure: dup->inport PORT/FD [NEWFD]
276 Returns a new input port using the new file descriptor.
278 *** procedure: dup->outport PORT/FD [NEWFD]
279 Returns a new output port using the new file descriptor.
281 *** procedure: dup PORT/FD [NEWFD]
282 Returns a new port if PORT/FD is a port, with the same mode as the
283 supplied port, otherwise returns an integer file descriptor.
285 *** procedure: dup->port PORT/FD MODE [NEWFD]
286 Returns a new port using the new file descriptor. MODE supplies a
287 mode string for the port (*note open-file: File Ports.).
289 *** procedure: setenv NAME VALUE
290 Modifies the environment of the current process, which is also the
291 default environment inherited by child processes.
293 If VALUE is `#f', then NAME is removed from the environment.
294 Otherwise, the string NAME=VALUE is added to the environment,
295 replacing any existing string with name matching NAME.
297 The return value is unspecified.
299 *** procedure: truncate-file OBJ SIZE
300 Truncates the file referred to by OBJ to at most SIZE bytes. OBJ
301 can be a string containing a file name or an integer file
302 descriptor or port open for output on the file. The underlying
303 system calls are `truncate' and `ftruncate'.
305 The return value is unspecified.
307 *** procedure: setvbuf PORT MODE [SIZE]
308 Set the buffering mode for PORT. MODE can be:
316 block buffered, using a newly allocated buffer of SIZE bytes.
317 However if SIZE is zero or unspecified, the port will be made
320 This procedure should not be used after I/O has been performed with
323 Ports are usually block buffered by default, with a default buffer
324 size. Procedures e.g., *Note open-file: File Ports, which accept a
325 mode string allow `0' to be added to request an unbuffered port.
327 *** procedure: fsync PORT/FD
328 Copies any unwritten data for the specified output file descriptor
329 to disk. If PORT/FD is a port, its buffer is flushed before the
330 underlying file descriptor is fsync'd. The return value is
333 *** procedure: open-fdes PATH FLAGS [MODES]
334 Similar to `open' but returns a file descriptor instead of a port.
336 *** procedure: execle PATH ENV [ARG] ...
337 Similar to `execl', but the environment of the new process is
338 specified by ENV, which must be a list of strings as returned by
339 the `environ' procedure.
341 This procedure is currently implemented using the `execve' system
342 call, but we call it `execle' because of its Scheme calling
345 *** procedure: strerror ERRNO
346 Returns the Unix error message corresponding to ERRNO, an integer.
348 *** procedure: primitive-exit [STATUS]
349 Terminate the current process without unwinding the Scheme stack.
350 This is would typically be useful after a fork. The exit status
351 is STATUS if supplied, otherwise zero.
354 Returns an object with information about real and processor time.
355 The following procedures accept such an object as an argument and
356 return a selected component:
359 The current real time, expressed as time units relative to an
363 The CPU time units used by the calling process.
366 The CPU time units used by the system on behalf of the
370 The CPU time units used by terminated child processes of the
371 calling process, whose status has been collected (e.g., using
375 Similarly, the CPU times units used by the system on behalf of
376 terminated child processes.
378 ** Removed: list-length
379 ** Removed: list-append, list-append!
380 ** Removed: list-reverse, list-reverse!
382 ** array-map renamed to array-map!
384 ** serial-array-map renamed to serial-array-map!
386 ** catch doesn't take #f as first argument any longer
388 Previously, it was possible to pass #f instead of a key to `catch'.
389 That would cause `catch' to pass a jump buffer object to the procedure
390 passed as second argument. The procedure could then use this jump
391 buffer objekt as an argument to throw.
393 This mechanism has been removed since its utility doesn't motivate the
394 extra complexity it introduces.
396 * Changes to the gh_ interface
398 ** The gh_enter function now takes care of loading the Guile startup files.
399 gh_enter works by calling scm_boot_guile; see the remarks below.
401 ** Function: void gh_write (SCM x)
403 Write the printed representation of the scheme object x to the current
404 output port. Corresponds to the scheme level `write'.
406 ** gh_list_length renamed to gh_length.
408 ** vector handling routines
410 Several major changes. In particular, gh_vector() now resembles
411 (vector ...) (with a caveat -- see manual), and gh_make_vector() now
412 exists and behaves like (make-vector ...). gh_vset() and gh_vref()
413 have been renamed gh_vector_set_x() and gh_vector_ref(). Some missing
414 vector-related gh_ functions have been implemented.
416 ** pair and list routines
418 Implemented several of the R4RS pair and list functions that were
421 ** gh_scm2doubles, gh_doubles2scm, gh_doubles2dvect
423 New function. Converts double arrays back and forth between Scheme
426 * Changes to the scm_ interface
428 ** The function scm_boot_guile now takes care of loading the startup files.
430 Guile's primary initialization function, scm_boot_guile, now takes
431 care of loading `boot-9.scm', in the `ice-9' module, to initialize
432 Guile, define the module system, and put together some standard
433 bindings. It also loads `init.scm', which is intended to hold
434 site-specific initialization code.
436 Since Guile cannot operate properly until boot-9.scm is loaded, there
437 is no reason to separate loading boot-9.scm from Guile's other
438 initialization processes.
440 This job used to be done by scm_compile_shell_switches, which didn't
441 make much sense; in particular, it meant that people using Guile for
442 non-shell-like applications had to jump through hoops to get Guile
443 initialized properly.
445 ** The function scm_compile_shell_switches no longer loads the startup files.
446 Now, Guile always loads the startup files, whenever it is initialized;
447 see the notes above for scm_boot_guile and scm_load_startup_files.
449 ** Function: scm_load_startup_files
450 This new function takes care of loading Guile's initialization file
451 (`boot-9.scm'), and the site initialization file, `init.scm'. Since
452 this is always called by the Guile initialization process, it's
453 probably not too useful to call this yourself, but it's there anyway.
455 ** The semantics of smob marking have changed slightly.
457 The smob marking function (the `mark' member of the scm_smobfuns
458 structure) is no longer responsible for setting the mark bit on the
459 smob. The generic smob handling code in the garbage collector will
460 set this bit. The mark function need only ensure that any other
461 objects the smob refers to get marked.
463 Note that this change means that the smob's GC8MARK bit is typically
464 already set upon entry to the mark function. Thus, marking functions
465 which look like this:
468 if (SCM_GC8MARKP (ptr))
470 SCM_SETGC8MARK (ptr);
471 ... mark objects to which the smob refers ...
474 are now incorrect, since they will return early, and fail to mark any
475 other objects the smob refers to. Some code in the Guile library used
479 ** Function: int scm_internal_select (int fds,
483 struct timeval *timeout);
485 This is a replacement for the `select' function provided by the OS.
486 It enables I/O blocking and sleeping to happen for one cooperative
487 thread without blocking other threads. It also avoids busy-loops in
488 these situations. It is intended that all I/O blocking and sleeping
489 will finally go through this function. Currently, this function is
490 only available on systems providing `gettimeofday' and `select'.
492 ** Function: SCM scm_internal_stack_catch (SCM tag,
493 scm_catch_body_t body,
495 scm_catch_handler_t handler,
498 A new sibling to the other two C level `catch' functions
499 scm_internal_catch and scm_internal_lazy_catch. Use it if you want
500 the stack to be saved automatically into the variable `the-last-stack'
501 (scm_the_last_stack_var) on error. This is necessary if you want to
502 use advanced error reporting, such as calling scm_display_error and
503 scm_display_backtrace. (They both take a stack object as argument.)
505 ** Function: SCM scm_spawn_thread (scm_catch_body_t body,
507 scm_catch_handler_t handler,
510 Spawns a new thread. It does a job similar to
511 scm_call_with_new_thread but takes arguments more suitable when
512 spawning threads from application C code.
514 ** The hook scm_error_callback has been removed. It was originally
515 intended as a way for the user to install his own error handler. But
516 that method works badly since it intervenes between throw and catch,
517 thereby changing the semantics of expressions like (catch #t ...).
518 The correct way to do it is to use one of the C level catch functions
519 in throw.c: scm_internal_catch/lazy_catch/stack_catch.
521 ** Removed functions:
523 scm_obj_length, scm_list_length, scm_list_append, scm_list_append_x,
524 scm_list_reverse, scm_list_reverse_x
526 ** New macros: SCM_LISTn where n is one of the integers 0-9.
528 These can be used for pretty list creation from C. The idea is taken
529 from Erick Gallesio's STk.
531 ** scm_array_map renamed to scm_array_map_x
533 ** mbstrings are now removed
535 This means that the type codes scm_tc7_mb_string and
536 scm_tc7_mb_substring has been removed.
538 ** The macros SCM_TYP7D and SCM_TYP7SD has been removed.
540 ** The macro SCM_TYP7S has taken the role of the old SCM_TYP7D
542 SCM_TYP7S now masks away the bit which distinguishes substrings from
545 ** All genio functions changed names and interfaces; new functions are
546 scm_putc, scm_puts, scm_lfwrite, scm_getc, scm_ungetc, and
549 ** scm_catch_body_t: Backward incompatible change!
551 Body functions to scm_internal_catch and friends do not any longer
552 take a second argument. This is because it is no longer possible to
553 pass a #f arg to catch.
556 Changes in Guile 1.2 (released Tuesday, June 24 1997):
558 * Changes to the distribution
560 ** Nightly snapshots are now available from ftp.red-bean.com.
561 The old server, ftp.cyclic.com, has been relinquished to its rightful
564 Nightly snapshots of the Guile development sources are now available via
565 anonymous FTP from ftp.red-bean.com, as /pub/guile/guile-snap.tar.gz.
567 Via the web, that's: ftp://ftp.red-bean.com/pub/guile/guile-snap.tar.gz
568 For getit, that's: ftp.red-bean.com:/pub/guile/guile-snap.tar.gz
570 ** To run Guile without installing it, the procedure has changed a bit.
572 If you used a separate build directory to compile Guile, you'll need
573 to include the build directory in SCHEME_LOAD_PATH, as well as the
574 source directory. See the `INSTALL' file for examples.
576 * Changes to the procedure for linking libguile with your programs
578 ** The standard Guile load path for Scheme code now includes
579 $(datadir)/guile (usually /usr/local/share/guile). This means that
580 you can install your own Scheme files there, and Guile will find them.
581 (Previous versions of Guile only checked a directory whose name
582 contained the Guile version number, so you had to re-install or move
583 your Scheme sources each time you installed a fresh version of Guile.)
585 The load path also includes $(datadir)/guile/site; we recommend
586 putting individual Scheme files there. If you want to install a
587 package with multiple source files, create a directory for them under
590 ** Guile 1.2 will now use the Rx regular expression library, if it is
591 installed on your system. When you are linking libguile into your own
592 programs, this means you will have to link against -lguile, -lqt (if
593 you configured Guile with thread support), and -lrx.
595 If you are using autoconf to generate configuration scripts for your
596 application, the following lines should suffice to add the appropriate
597 libraries to your link command:
599 ### Find Rx, quickthreads and libguile.
600 AC_CHECK_LIB(rx, main)
601 AC_CHECK_LIB(qt, main)
602 AC_CHECK_LIB(guile, scm_shell)
604 The Guile 1.2 distribution does not contain sources for the Rx
605 library, as Guile 1.0 did. If you want to use Rx, you'll need to
606 retrieve it from a GNU FTP site and install it separately.
608 * Changes to Scheme functions and syntax
610 ** The dynamic linking features of Guile are now enabled by default.
611 You can disable them by giving the `--disable-dynamic-linking' option
614 (dynamic-link FILENAME)
616 Find the object file denoted by FILENAME (a string) and link it
617 into the running Guile application. When everything works out,
618 return a Scheme object suitable for representing the linked object
619 file. Otherwise an error is thrown. How object files are
620 searched is system dependent.
622 (dynamic-object? VAL)
624 Determine whether VAL represents a dynamically linked object file.
626 (dynamic-unlink DYNOBJ)
628 Unlink the indicated object file from the application. DYNOBJ
629 should be one of the values returned by `dynamic-link'.
631 (dynamic-func FUNCTION DYNOBJ)
633 Search the C function indicated by FUNCTION (a string or symbol)
634 in DYNOBJ and return some Scheme object that can later be used
635 with `dynamic-call' to actually call this function. Right now,
636 these Scheme objects are formed by casting the address of the
637 function to `long' and converting this number to its Scheme
640 (dynamic-call FUNCTION DYNOBJ)
642 Call the C function indicated by FUNCTION and DYNOBJ. The
643 function is passed no arguments and its return value is ignored.
644 When FUNCTION is something returned by `dynamic-func', call that
645 function and ignore DYNOBJ. When FUNCTION is a string (or symbol,
646 etc.), look it up in DYNOBJ; this is equivalent to
648 (dynamic-call (dynamic-func FUNCTION DYNOBJ) #f)
650 Interrupts are deferred while the C function is executing (with
651 SCM_DEFER_INTS/SCM_ALLOW_INTS).
653 (dynamic-args-call FUNCTION DYNOBJ ARGS)
655 Call the C function indicated by FUNCTION and DYNOBJ, but pass it
656 some arguments and return its return value. The C function is
657 expected to take two arguments and return an `int', just like
660 int c_func (int argc, char **argv);
662 ARGS must be a list of strings and is converted into an array of
663 `char *'. The array is passed in ARGV and its size in ARGC. The
664 return value is converted to a Scheme number and returned from the
665 call to `dynamic-args-call'.
667 When dynamic linking is disabled or not supported on your system,
668 the above functions throw errors, but they are still available.
670 Here is a small example that works on GNU/Linux:
672 (define libc-obj (dynamic-link "libc.so"))
673 (dynamic-args-call 'rand libc-obj '())
675 See the file `libguile/DYNAMIC-LINKING' for additional comments.
677 ** The #/ syntax for module names is depreciated, and will be removed
678 in a future version of Guile. Instead of
686 The latter syntax is more consistent with existing Lisp practice.
688 ** Guile now does fancier printing of structures. Structures are the
689 underlying implementation for records, which in turn are used to
690 implement modules, so all of these object now print differently and in
691 a more informative way.
693 The Scheme printer will examine the builtin variable *struct-printer*
694 whenever it needs to print a structure object. When this variable is
695 not `#f' it is deemed to be a procedure and will be applied to the
696 structure object and the output port. When *struct-printer* is `#f'
697 or the procedure return `#f' the structure object will be printed in
698 the boring #<struct 80458270> form.
700 This hook is used by some routines in ice-9/boot-9.scm to implement
701 type specific printing routines. Please read the comments there about
704 One of the more specific uses of structs are records. The printing
705 procedure that could be passed to MAKE-RECORD-TYPE is now actually
706 called. It should behave like a *struct-printer* procedure (described
709 ** Guile now supports a new R4RS-compliant syntax for keywords. A
710 token of the form #:NAME, where NAME has the same syntax as a Scheme
711 symbol, is the external representation of the keyword named NAME.
712 Keyword objects print using this syntax as well, so values containing
713 keyword objects can be read back into Guile. When used in an
714 expression, keywords are self-quoting objects.
716 Guile suports this read syntax, and uses this print syntax, regardless
717 of the current setting of the `keyword' read option. The `keyword'
718 read option only controls whether Guile recognizes the `:NAME' syntax,
719 which is incompatible with R4RS. (R4RS says such token represent
722 ** Guile has regular expression support again. Guile 1.0 included
723 functions for matching regular expressions, based on the Rx library.
724 In Guile 1.1, the Guile/Rx interface was removed to simplify the
725 distribution, and thus Guile had no regular expression support. Guile
726 1.2 again supports the most commonly used functions, and supports all
727 of SCSH's regular expression functions.
729 If your system does not include a POSIX regular expression library,
730 and you have not linked Guile with a third-party regexp library such as
731 Rx, these functions will not be available. You can tell whether your
732 Guile installation includes regular expression support by checking
733 whether the `*features*' list includes the `regex' symbol.
737 By default, Guile supports POSIX extended regular expressions. That
738 means that the characters `(', `)', `+' and `?' are special, and must
739 be escaped if you wish to match the literal characters.
741 This regular expression interface was modeled after that implemented
742 by SCSH, the Scheme Shell. It is intended to be upwardly compatible
743 with SCSH regular expressions.
745 **** Function: string-match PATTERN STR [START]
746 Compile the string PATTERN into a regular expression and compare
747 it with STR. The optional numeric argument START specifies the
748 position of STR at which to begin matching.
750 `string-match' returns a "match structure" which describes what,
751 if anything, was matched by the regular expression. *Note Match
752 Structures::. If STR does not match PATTERN at all,
753 `string-match' returns `#f'.
755 Each time `string-match' is called, it must compile its PATTERN
756 argument into a regular expression structure. This operation is
757 expensive, which makes `string-match' inefficient if the same regular
758 expression is used several times (for example, in a loop). For better
759 performance, you can compile a regular expression in advance and then
760 match strings against the compiled regexp.
762 **** Function: make-regexp STR [FLAGS]
763 Compile the regular expression described by STR, and return the
764 compiled regexp structure. If STR does not describe a legal
765 regular expression, `make-regexp' throws a
766 `regular-expression-syntax' error.
768 FLAGS may be the bitwise-or of one or more of the following:
770 **** Constant: regexp/extended
771 Use POSIX Extended Regular Expression syntax when interpreting
772 STR. If not set, POSIX Basic Regular Expression syntax is used.
773 If the FLAGS argument is omitted, we assume regexp/extended.
775 **** Constant: regexp/icase
776 Do not differentiate case. Subsequent searches using the
777 returned regular expression will be case insensitive.
779 **** Constant: regexp/newline
780 Match-any-character operators don't match a newline.
782 A non-matching list ([^...]) not containing a newline matches a
785 Match-beginning-of-line operator (^) matches the empty string
786 immediately after a newline, regardless of whether the FLAGS
787 passed to regexp-exec contain regexp/notbol.
789 Match-end-of-line operator ($) matches the empty string
790 immediately before a newline, regardless of whether the FLAGS
791 passed to regexp-exec contain regexp/noteol.
793 **** Function: regexp-exec REGEXP STR [START [FLAGS]]
794 Match the compiled regular expression REGEXP against `str'. If
795 the optional integer START argument is provided, begin matching
796 from that position in the string. Return a match structure
797 describing the results of the match, or `#f' if no match could be
800 FLAGS may be the bitwise-or of one or more of the following:
802 **** Constant: regexp/notbol
803 The match-beginning-of-line operator always fails to match (but
804 see the compilation flag regexp/newline above) This flag may be
805 used when different portions of a string are passed to
806 regexp-exec and the beginning of the string should not be
807 interpreted as the beginning of the line.
809 **** Constant: regexp/noteol
810 The match-end-of-line operator always fails to match (but see the
811 compilation flag regexp/newline above)
813 **** Function: regexp? OBJ
814 Return `#t' if OBJ is a compiled regular expression, or `#f'
817 Regular expressions are commonly used to find patterns in one string
818 and replace them with the contents of another string.
820 **** Function: regexp-substitute PORT MATCH [ITEM...]
821 Write to the output port PORT selected contents of the match
822 structure MATCH. Each ITEM specifies what should be written, and
823 may be one of the following arguments:
825 * A string. String arguments are written out verbatim.
827 * An integer. The submatch with that number is written.
829 * The symbol `pre'. The portion of the matched string preceding
830 the regexp match is written.
832 * The symbol `post'. The portion of the matched string
833 following the regexp match is written.
835 PORT may be `#f', in which case nothing is written; instead,
836 `regexp-substitute' constructs a string from the specified ITEMs
839 **** Function: regexp-substitute/global PORT REGEXP TARGET [ITEM...]
840 Similar to `regexp-substitute', but can be used to perform global
841 substitutions on STR. Instead of taking a match structure as an
842 argument, `regexp-substitute/global' takes two string arguments: a
843 REGEXP string describing a regular expression, and a TARGET string
844 which should be matched against this regular expression.
846 Each ITEM behaves as in REGEXP-SUBSTITUTE, with the following
849 * A function may be supplied. When this function is called, it
850 will be passed one argument: a match structure for a given
851 regular expression match. It should return a string to be
854 * The `post' symbol causes `regexp-substitute/global' to recurse
855 on the unmatched portion of STR. This *must* be supplied in
856 order to perform global search-and-replace on STR; if it is
857 not present among the ITEMs, then `regexp-substitute/global'
858 will return after processing a single match.
862 A "match structure" is the object returned by `string-match' and
863 `regexp-exec'. It describes which portion of a string, if any, matched
864 the given regular expression. Match structures include: a reference to
865 the string that was checked for matches; the starting and ending
866 positions of the regexp match; and, if the regexp included any
867 parenthesized subexpressions, the starting and ending positions of each
870 In each of the regexp match functions described below, the `match'
871 argument must be a match structure returned by a previous call to
872 `string-match' or `regexp-exec'. Most of these functions return some
873 information about the original target string that was matched against a
874 regular expression; we will call that string TARGET for easy reference.
876 **** Function: regexp-match? OBJ
877 Return `#t' if OBJ is a match structure returned by a previous
878 call to `regexp-exec', or `#f' otherwise.
880 **** Function: match:substring MATCH [N]
881 Return the portion of TARGET matched by subexpression number N.
882 Submatch 0 (the default) represents the entire regexp match. If
883 the regular expression as a whole matched, but the subexpression
884 number N did not match, return `#f'.
886 **** Function: match:start MATCH [N]
887 Return the starting position of submatch number N.
889 **** Function: match:end MATCH [N]
890 Return the ending position of submatch number N.
892 **** Function: match:prefix MATCH
893 Return the unmatched portion of TARGET preceding the regexp match.
895 **** Function: match:suffix MATCH
896 Return the unmatched portion of TARGET following the regexp match.
898 **** Function: match:count MATCH
899 Return the number of parenthesized subexpressions from MATCH.
900 Note that the entire regular expression match itself counts as a
901 subexpression, and failed submatches are included in the count.
903 **** Function: match:string MATCH
904 Return the original TARGET string.
906 *** Backslash Escapes
908 Sometimes you will want a regexp to match characters like `*' or `$'
909 exactly. For example, to check whether a particular string represents
910 a menu entry from an Info node, it would be useful to match it against
911 a regexp like `^* [^:]*::'. However, this won't work; because the
912 asterisk is a metacharacter, it won't match the `*' at the beginning of
913 the string. In this case, we want to make the first asterisk un-magic.
915 You can do this by preceding the metacharacter with a backslash
916 character `\'. (This is also called "quoting" the metacharacter, and
917 is known as a "backslash escape".) When Guile sees a backslash in a
918 regular expression, it considers the following glyph to be an ordinary
919 character, no matter what special meaning it would ordinarily have.
920 Therefore, we can make the above example work by changing the regexp to
921 `^\* [^:]*::'. The `\*' sequence tells the regular expression engine
922 to match only a single asterisk in the target string.
924 Since the backslash is itself a metacharacter, you may force a
925 regexp to match a backslash in the target string by preceding the
926 backslash with itself. For example, to find variable references in a
927 TeX program, you might want to find occurrences of the string `\let\'
928 followed by any number of alphabetic characters. The regular expression
929 `\\let\\[A-Za-z]*' would do this: the double backslashes in the regexp
930 each match a single backslash in the target string.
932 **** Function: regexp-quote STR
933 Quote each special character found in STR with a backslash, and
934 return the resulting string.
936 *Very important:* Using backslash escapes in Guile source code (as
937 in Emacs Lisp or C) can be tricky, because the backslash character has
938 special meaning for the Guile reader. For example, if Guile encounters
939 the character sequence `\n' in the middle of a string while processing
940 Scheme code, it replaces those characters with a newline character.
941 Similarly, the character sequence `\t' is replaced by a horizontal tab.
942 Several of these "escape sequences" are processed by the Guile reader
943 before your code is executed. Unrecognized escape sequences are
944 ignored: if the characters `\*' appear in a string, they will be
945 translated to the single character `*'.
947 This translation is obviously undesirable for regular expressions,
948 since we want to be able to include backslashes in a string in order to
949 escape regexp metacharacters. Therefore, to make sure that a backslash
950 is preserved in a string in your Guile program, you must use *two*
951 consecutive backslashes:
953 (define Info-menu-entry-pattern (make-regexp "^\\* [^:]*"))
955 The string in this example is preprocessed by the Guile reader before
956 any code is executed. The resulting argument to `make-regexp' is the
957 string `^\* [^:]*', which is what we really want.
959 This also means that in order to write a regular expression that
960 matches a single backslash character, the regular expression string in
961 the source code must include *four* backslashes. Each consecutive pair
962 of backslashes gets translated by the Guile reader to a single
963 backslash, and the resulting double-backslash is interpreted by the
964 regexp engine as matching a single backslash character. Hence:
966 (define tex-variable-pattern (make-regexp "\\\\let\\\\=[A-Za-z]*"))
968 The reason for the unwieldiness of this syntax is historical. Both
969 regular expression pattern matchers and Unix string processing systems
970 have traditionally used backslashes with the special meanings described
971 above. The POSIX regular expression specification and ANSI C standard
972 both require these semantics. Attempting to abandon either convention
973 would cause other kinds of compatibility problems, possibly more severe
974 ones. Therefore, without extending the Scheme reader to support
975 strings with different quoting conventions (an ungainly and confusing
976 extension when implemented in other languages), we must adhere to this
977 cumbersome escape syntax.
979 * Changes to the gh_ interface
981 * Changes to the scm_ interface
983 * Changes to system call interfaces:
985 ** The value returned by `raise' is now unspecified. It throws an exception
988 *** A new procedure `sigaction' can be used to install signal handlers
990 (sigaction signum [action] [flags])
992 signum is the signal number, which can be specified using the value
995 If action is omitted, sigaction returns a pair: the CAR is the current
996 signal hander, which will be either an integer with the value SIG_DFL
997 (default action) or SIG_IGN (ignore), or the Scheme procedure which
998 handles the signal, or #f if a non-Scheme procedure handles the
999 signal. The CDR contains the current sigaction flags for the handler.
1001 If action is provided, it is installed as the new handler for signum.
1002 action can be a Scheme procedure taking one argument, or the value of
1003 SIG_DFL (default action) or SIG_IGN (ignore), or #f to restore
1004 whatever signal handler was installed before sigaction was first used.
1005 Flags can optionally be specified for the new handler (SA_RESTART is
1006 always used if the system provides it, so need not be specified.) The
1007 return value is a pair with information about the old handler as
1010 This interface does not provide access to the "signal blocking"
1011 facility. Maybe this is not needed, since the thread support may
1012 provide solutions to the problem of consistent access to data
1015 *** A new procedure `flush-all-ports' is equivalent to running
1016 `force-output' on every port open for output.
1018 ** Guile now provides information on how it was built, via the new
1019 global variable, %guile-build-info. This variable records the values
1020 of the standard GNU makefile directory variables as an assocation
1021 list, mapping variable names (symbols) onto directory paths (strings).
1022 For example, to find out where the Guile link libraries were
1023 installed, you can say:
1025 guile -c "(display (assq-ref %guile-build-info 'libdir)) (newline)"
1028 * Changes to the scm_ interface
1030 ** The new function scm_handle_by_message_noexit is just like the
1031 existing scm_handle_by_message function, except that it doesn't call
1032 exit to terminate the process. Instead, it prints a message and just
1033 returns #f. This might be a more appropriate catch-all handler for
1034 new dynamic roots and threads.
1037 Changes in Guile 1.1 (released Friday, May 16 1997):
1039 * Changes to the distribution.
1041 The Guile 1.0 distribution has been split up into several smaller
1043 guile-core --- the Guile interpreter itself.
1044 guile-tcltk --- the interface between the Guile interpreter and
1045 Tcl/Tk; Tcl is an interpreter for a stringy language, and Tk
1046 is a toolkit for building graphical user interfaces.
1047 guile-rgx-ctax --- the interface between Guile and the Rx regular
1048 expression matcher, and the translator for the Ctax
1049 programming language. These are packaged together because the
1050 Ctax translator uses Rx to parse Ctax source code.
1052 This NEWS file describes the changes made to guile-core since the 1.0
1055 We no longer distribute the documentation, since it was either out of
1056 date, or incomplete. As soon as we have current documentation, we
1061 * Changes to the stand-alone interpreter
1063 ** guile now accepts command-line arguments compatible with SCSH, Olin
1064 Shivers' Scheme Shell.
1066 In general, arguments are evaluated from left to right, but there are
1067 exceptions. The following switches stop argument processing, and
1068 stash all remaining command-line arguments as the value returned by
1069 the (command-line) function.
1070 -s SCRIPT load Scheme source code from FILE, and exit
1071 -c EXPR evalute Scheme expression EXPR, and exit
1072 -- stop scanning arguments; run interactively
1074 The switches below are processed as they are encountered.
1075 -l FILE load Scheme source code from FILE
1076 -e FUNCTION after reading script, apply FUNCTION to
1077 command line arguments
1078 -ds do -s script at this point
1079 --emacs enable Emacs protocol (experimental)
1080 -h, --help display this help and exit
1081 -v, --version display version information and exit
1082 \ read arguments from following script lines
1084 So, for example, here is a Guile script named `ekko' (thanks, Olin)
1085 which re-implements the traditional "echo" command:
1087 #!/usr/local/bin/guile -s
1090 (map (lambda (arg) (display arg) (display " "))
1094 (main (command-line))
1096 Suppose we invoke this script as follows:
1098 ekko a speckled gecko
1100 Through the magic of Unix script processing (triggered by the `#!'
1101 token at the top of the file), /usr/local/bin/guile receives the
1102 following list of command-line arguments:
1104 ("-s" "./ekko" "a" "speckled" "gecko")
1106 Unix inserts the name of the script after the argument specified on
1107 the first line of the file (in this case, "-s"), and then follows that
1108 with the arguments given to the script. Guile loads the script, which
1109 defines the `main' function, and then applies it to the list of
1110 remaining command-line arguments, ("a" "speckled" "gecko").
1112 In Unix, the first line of a script file must take the following form:
1114 #!INTERPRETER ARGUMENT
1116 where INTERPRETER is the absolute filename of the interpreter
1117 executable, and ARGUMENT is a single command-line argument to pass to
1120 You may only pass one argument to the interpreter, and its length is
1121 limited. These restrictions can be annoying to work around, so Guile
1122 provides a general mechanism (borrowed from, and compatible with,
1123 SCSH) for circumventing them.
1125 If the ARGUMENT in a Guile script is a single backslash character,
1126 `\', Guile will open the script file, parse arguments from its second
1127 and subsequent lines, and replace the `\' with them. So, for example,
1128 here is another implementation of the `ekko' script:
1130 #!/usr/local/bin/guile \
1134 (for-each (lambda (arg) (display arg) (display " "))
1138 If the user invokes this script as follows:
1140 ekko a speckled gecko
1142 Unix expands this into
1144 /usr/local/bin/guile \ ekko a speckled gecko
1146 When Guile sees the `\' argument, it replaces it with the arguments
1147 read from the second line of the script, producing:
1149 /usr/local/bin/guile -e main -s ekko a speckled gecko
1151 This tells Guile to load the `ekko' script, and apply the function
1152 `main' to the argument list ("a" "speckled" "gecko").
1154 Here is how Guile parses the command-line arguments:
1155 - Each space character terminates an argument. This means that two
1156 spaces in a row introduce an empty-string argument.
1157 - The tab character is not permitted (unless you quote it with the
1158 backslash character, as described below), to avoid confusion.
1159 - The newline character terminates the sequence of arguments, and will
1160 also terminate a final non-empty argument. (However, a newline
1161 following a space will not introduce a final empty-string argument;
1162 it only terminates the argument list.)
1163 - The backslash character is the escape character. It escapes
1164 backslash, space, tab, and newline. The ANSI C escape sequences
1165 like \n and \t are also supported. These produce argument
1166 constituents; the two-character combination \n doesn't act like a
1167 terminating newline. The escape sequence \NNN for exactly three
1168 octal digits reads as the character whose ASCII code is NNN. As
1169 above, characters produced this way are argument constituents.
1170 Backslash followed by other characters is not allowed.
1172 * Changes to the procedure for linking libguile with your programs
1174 ** Guile now builds and installs a shared guile library, if your
1175 system support shared libraries. (It still builds a static library on
1176 all systems.) Guile automatically detects whether your system
1177 supports shared libraries. To prevent Guile from buildisg shared
1178 libraries, pass the `--disable-shared' flag to the configure script.
1180 Guile takes longer to compile when it builds shared libraries, because
1181 it must compile every file twice --- once to produce position-
1182 independent object code, and once to produce normal object code.
1184 ** The libthreads library has been merged into libguile.
1186 To link a program against Guile, you now need only link against
1187 -lguile and -lqt; -lthreads is no longer needed. If you are using
1188 autoconf to generate configuration scripts for your application, the
1189 following lines should suffice to add the appropriate libraries to
1192 ### Find quickthreads and libguile.
1193 AC_CHECK_LIB(qt, main)
1194 AC_CHECK_LIB(guile, scm_shell)
1196 * Changes to Scheme functions
1198 ** Guile Scheme's special syntax for keyword objects is now optional,
1199 and disabled by default.
1201 The syntax variation from R4RS made it difficult to port some
1202 interesting packages to Guile. The routines which accepted keyword
1203 arguments (mostly in the module system) have been modified to also
1204 accept symbols whose names begin with `:'.
1206 To change the keyword syntax, you must first import the (ice-9 debug)
1208 (use-modules (ice-9 debug))
1210 Then you can enable the keyword syntax as follows:
1211 (read-set! keywords 'prefix)
1213 To disable keyword syntax, do this:
1214 (read-set! keywords #f)
1216 ** Many more primitive functions accept shared substrings as
1217 arguments. In the past, these functions required normal, mutable
1218 strings as arguments, although they never made use of this
1221 ** The uniform array functions now operate on byte vectors. These
1222 functions are `array-fill!', `serial-array-copy!', `array-copy!',
1223 `serial-array-map', `array-map', `array-for-each', and
1226 ** The new functions `trace' and `untrace' implement simple debugging
1227 support for Scheme functions.
1229 The `trace' function accepts any number of procedures as arguments,
1230 and tells the Guile interpreter to display each procedure's name and
1231 arguments each time the procedure is invoked. When invoked with no
1232 arguments, `trace' returns the list of procedures currently being
1235 The `untrace' function accepts any number of procedures as arguments,
1236 and tells the Guile interpreter not to trace them any more. When
1237 invoked with no arguments, `untrace' untraces all curretly traced
1240 The tracing in Guile has an advantage over most other systems: we
1241 don't create new procedure objects, but mark the procedure objects
1242 themselves. This means that anonymous and internal procedures can be
1245 ** The function `assert-repl-prompt' has been renamed to
1246 `set-repl-prompt!'. It takes one argument, PROMPT.
1247 - If PROMPT is #f, the Guile read-eval-print loop will not prompt.
1248 - If PROMPT is a string, we use it as a prompt.
1249 - If PROMPT is a procedure accepting no arguments, we call it, and
1250 display the result as a prompt.
1251 - Otherwise, we display "> ".
1253 ** The new function `eval-string' reads Scheme expressions from a
1254 string and evaluates them, returning the value of the last expression
1255 in the string. If the string contains no expressions, it returns an
1258 ** The new function `thunk?' returns true iff its argument is a
1259 procedure of zero arguments.
1261 ** `defined?' is now a builtin function, instead of syntax. This
1262 means that its argument should be quoted. It returns #t iff its
1263 argument is bound in the current module.
1265 ** The new syntax `use-modules' allows you to add new modules to your
1266 environment without re-typing a complete `define-module' form. It
1267 accepts any number of module names as arguments, and imports their
1268 public bindings into the current module.
1270 ** The new function (module-defined? NAME MODULE) returns true iff
1271 NAME, a symbol, is defined in MODULE, a module object.
1273 ** The new function `builtin-bindings' creates and returns a hash
1274 table containing copies of all the root module's bindings.
1276 ** The new function `builtin-weak-bindings' does the same as
1277 `builtin-bindings', but creates a doubly-weak hash table.
1279 ** The `equal?' function now considers variable objects to be
1280 equivalent if they have the same name and the same value.
1282 ** The new function `command-line' returns the command-line arguments
1283 given to Guile, as a list of strings.
1285 When using guile as a script interpreter, `command-line' returns the
1286 script's arguments; those processed by the interpreter (like `-s' or
1287 `-c') are omitted. (In other words, you get the normal, expected
1288 behavior.) Any application that uses scm_shell to process its
1289 command-line arguments gets this behavior as well.
1291 ** The new function `load-user-init' looks for a file called `.guile'
1292 in the user's home directory, and loads it if it exists. This is
1293 mostly for use by the code generated by scm_compile_shell_switches,
1294 but we thought it might also be useful in other circumstances.
1296 ** The new function `log10' returns the base-10 logarithm of its
1299 ** Changes to I/O functions
1301 *** The functions `read', `primitive-load', `read-and-eval!', and
1302 `primitive-load-path' no longer take optional arguments controlling
1303 case insensitivity and a `#' parser.
1305 Case sensitivity is now controlled by a read option called
1306 `case-insensitive'. The user can add new `#' syntaxes with the
1307 `read-hash-extend' function (see below).
1309 *** The new function `read-hash-extend' allows the user to change the
1310 syntax of Guile Scheme in a somewhat controlled way.
1312 (read-hash-extend CHAR PROC)
1313 When parsing S-expressions, if we read a `#' character followed by
1314 the character CHAR, use PROC to parse an object from the stream.
1315 If PROC is #f, remove any parsing procedure registered for CHAR.
1317 The reader applies PROC to two arguments: CHAR and an input port.
1319 *** The new functions read-delimited and read-delimited! provide a
1320 general mechanism for doing delimited input on streams.
1322 (read-delimited DELIMS [PORT HANDLE-DELIM])
1323 Read until we encounter one of the characters in DELIMS (a string),
1324 or end-of-file. PORT is the input port to read from; it defaults to
1325 the current input port. The HANDLE-DELIM parameter determines how
1326 the terminating character is handled; it should be one of the
1329 'trim omit delimiter from result
1330 'peek leave delimiter character in input stream
1331 'concat append delimiter character to returned value
1332 'split return a pair: (RESULT . TERMINATOR)
1334 HANDLE-DELIM defaults to 'peek.
1336 (read-delimited! DELIMS BUF [PORT HANDLE-DELIM START END])
1337 A side-effecting variant of `read-delimited'.
1339 The data is written into the string BUF at the indices in the
1340 half-open interval [START, END); the default interval is the whole
1341 string: START = 0 and END = (string-length BUF). The values of
1342 START and END must specify a well-defined interval in BUF, i.e.
1343 0 <= START <= END <= (string-length BUF).
1345 It returns NBYTES, the number of bytes read. If the buffer filled
1346 up without a delimiter character being found, it returns #f. If the
1347 port is at EOF when the read starts, it returns the EOF object.
1349 If an integer is returned (i.e., the read is successfully terminated
1350 by reading a delimiter character), then the HANDLE-DELIM parameter
1351 determines how to handle the terminating character. It is described
1352 above, and defaults to 'peek.
1354 (The descriptions of these functions were borrowed from the SCSH
1355 manual, by Olin Shivers and Brian Carlstrom.)
1357 *** The `%read-delimited!' function is the primitive used to implement
1358 `read-delimited' and `read-delimited!'.
1360 (%read-delimited! DELIMS BUF GOBBLE? [PORT START END])
1362 This returns a pair of values: (TERMINATOR . NUM-READ).
1363 - TERMINATOR describes why the read was terminated. If it is a
1364 character or the eof object, then that is the value that terminated
1365 the read. If it is #f, the function filled the buffer without finding
1366 a delimiting character.
1367 - NUM-READ is the number of characters read into BUF.
1369 If the read is successfully terminated by reading a delimiter
1370 character, then the gobble? parameter determines what to do with the
1371 terminating character. If true, the character is removed from the
1372 input stream; if false, the character is left in the input stream
1373 where a subsequent read operation will retrieve it. In either case,
1374 the character is also the first value returned by the procedure call.
1376 (The descriptions of this function was borrowed from the SCSH manual,
1377 by Olin Shivers and Brian Carlstrom.)
1379 *** The `read-line' and `read-line!' functions have changed; they now
1380 trim the terminator by default; previously they appended it to the
1381 returned string. For the old behavior, use (read-line PORT 'concat).
1383 *** The functions `uniform-array-read!' and `uniform-array-write!' now
1384 take new optional START and END arguments, specifying the region of
1385 the array to read and write.
1387 *** The `ungetc-char-ready?' function has been removed. We feel it's
1388 inappropriate for an interface to expose implementation details this
1391 ** Changes to the Unix library and system call interface
1393 *** The new fcntl function provides access to the Unix `fcntl' system
1396 (fcntl PORT COMMAND VALUE)
1397 Apply COMMAND to PORT's file descriptor, with VALUE as an argument.
1398 Values for COMMAND are:
1400 F_DUPFD duplicate a file descriptor
1401 F_GETFD read the descriptor's close-on-exec flag
1402 F_SETFD set the descriptor's close-on-exec flag to VALUE
1403 F_GETFL read the descriptor's flags, as set on open
1404 F_SETFL set the descriptor's flags, as set on open to VALUE
1405 F_GETOWN return the process ID of a socket's owner, for SIGIO
1406 F_SETOWN set the process that owns a socket to VALUE, for SIGIO
1407 FD_CLOEXEC not sure what this is
1409 For details, see the documentation for the fcntl system call.
1411 *** The arguments to `select' have changed, for compatibility with
1412 SCSH. The TIMEOUT parameter may now be non-integral, yielding the
1413 expected behavior. The MILLISECONDS parameter has been changed to
1414 MICROSECONDS, to more closely resemble the underlying system call.
1415 The RVEC, WVEC, and EVEC arguments can now be vectors; the type of the
1416 corresponding return set will be the same.
1418 *** The arguments to the `mknod' system call have changed. They are
1421 (mknod PATH TYPE PERMS DEV)
1422 Create a new file (`node') in the file system. PATH is the name of
1423 the file to create. TYPE is the kind of file to create; it should
1424 be 'fifo, 'block-special, or 'char-special. PERMS specifies the
1425 permission bits to give the newly created file. If TYPE is
1426 'block-special or 'char-special, DEV specifies which device the
1427 special file refers to; its interpretation depends on the kind of
1428 special file being created.
1430 *** The `fork' function has been renamed to `primitive-fork', to avoid
1431 clashing with various SCSH forks.
1433 *** The `recv' and `recvfrom' functions have been renamed to `recv!'
1434 and `recvfrom!'. They no longer accept a size for a second argument;
1435 you must pass a string to hold the received value. They no longer
1436 return the buffer. Instead, `recv' returns the length of the message
1437 received, and `recvfrom' returns a pair containing the packet's length
1438 and originating address.
1440 *** The file descriptor datatype has been removed, as have the
1441 `read-fd', `write-fd', `close', `lseek', and `dup' functions.
1442 We plan to replace these functions with a SCSH-compatible interface.
1444 *** The `create' function has been removed; it's just a special case
1447 *** There are new functions to break down process termination status
1448 values. In the descriptions below, STATUS is a value returned by
1451 (status:exit-val STATUS)
1452 If the child process exited normally, this function returns the exit
1453 code for the child process (i.e., the value passed to exit, or
1454 returned from main). If the child process did not exit normally,
1455 this function returns #f.
1457 (status:stop-sig STATUS)
1458 If the child process was suspended by a signal, this function
1459 returns the signal that suspended the child. Otherwise, it returns
1462 (status:term-sig STATUS)
1463 If the child process terminated abnormally, this function returns
1464 the signal that terminated the child. Otherwise, this function
1467 POSIX promises that exactly one of these functions will return true on
1468 a valid STATUS value.
1470 These functions are compatible with SCSH.
1472 *** There are new accessors and setters for the broken-out time vectors
1473 returned by `localtime', `gmtime', and that ilk. They are:
1475 Component Accessor Setter
1476 ========================= ============ ============
1477 seconds tm:sec set-tm:sec
1478 minutes tm:min set-tm:min
1479 hours tm:hour set-tm:hour
1480 day of the month tm:mday set-tm:mday
1481 month tm:mon set-tm:mon
1482 year tm:year set-tm:year
1483 day of the week tm:wday set-tm:wday
1484 day in the year tm:yday set-tm:yday
1485 daylight saving time tm:isdst set-tm:isdst
1486 GMT offset, seconds tm:gmtoff set-tm:gmtoff
1487 name of time zone tm:zone set-tm:zone
1489 *** There are new accessors for the vectors returned by `uname',
1490 describing the host system:
1493 ============================================== ================
1494 name of the operating system implementation utsname:sysname
1495 network name of this machine utsname:nodename
1496 release level of the operating system utsname:release
1497 version level of the operating system utsname:version
1498 machine hardware platform utsname:machine
1500 *** There are new accessors for the vectors returned by `getpw',
1501 `getpwnam', `getpwuid', and `getpwent', describing entries from the
1502 system's user database:
1505 ====================== =================
1506 user name passwd:name
1507 user password passwd:passwd
1510 real name passwd:gecos
1511 home directory passwd:dir
1512 shell program passwd:shell
1514 *** There are new accessors for the vectors returned by `getgr',
1515 `getgrnam', `getgrgid', and `getgrent', describing entries from the
1516 system's group database:
1519 ======================= ============
1520 group name group:name
1521 group password group:passwd
1523 group members group:mem
1525 *** There are new accessors for the vectors returned by `gethost',
1526 `gethostbyaddr', `gethostbyname', and `gethostent', describing
1530 ========================= ===============
1531 official name of host hostent:name
1532 alias list hostent:aliases
1533 host address type hostent:addrtype
1534 length of address hostent:length
1535 list of addresses hostent:addr-list
1537 *** There are new accessors for the vectors returned by `getnet',
1538 `getnetbyaddr', `getnetbyname', and `getnetent', describing internet
1542 ========================= ===============
1543 official name of net netent:name
1544 alias list netent:aliases
1545 net number type netent:addrtype
1546 net number netent:net
1548 *** There are new accessors for the vectors returned by `getproto',
1549 `getprotobyname', `getprotobynumber', and `getprotoent', describing
1553 ========================= ===============
1554 official protocol name protoent:name
1555 alias list protoent:aliases
1556 protocol number protoent:proto
1558 *** There are new accessors for the vectors returned by `getserv',
1559 `getservbyname', `getservbyport', and `getservent', describing
1563 ========================= ===============
1564 official service name servent:name
1565 alias list servent:aliases
1566 port number servent:port
1567 protocol to use servent:proto
1569 *** There are new accessors for the sockaddr structures returned by
1570 `accept', `getsockname', `getpeername', `recvfrom!':
1573 ======================================== ===============
1574 address format (`family') sockaddr:fam
1575 path, for file domain addresses sockaddr:path
1576 address, for internet domain addresses sockaddr:addr
1577 TCP or UDP port, for internet sockaddr:port
1579 *** The `getpwent', `getgrent', `gethostent', `getnetent',
1580 `getprotoent', and `getservent' functions now return #f at the end of
1581 the user database. (They used to throw an exception.)
1583 Note that calling MUMBLEent function is equivalent to calling the
1584 corresponding MUMBLE function with no arguments.
1586 *** The `setpwent', `setgrent', `sethostent', `setnetent',
1587 `setprotoent', and `setservent' routines now take no arguments.
1589 *** The `gethost', `getproto', `getnet', and `getserv' functions now
1590 provide more useful information when they throw an exception.
1592 *** The `lnaof' function has been renamed to `inet-lnaof'.
1594 *** Guile now claims to have the `current-time' feature.
1596 *** The `mktime' function now takes an optional second argument ZONE,
1597 giving the time zone to use for the conversion. ZONE should be a
1598 string, in the same format as expected for the "TZ" environment variable.
1600 *** The `strptime' function now returns a pair (TIME . COUNT), where
1601 TIME is the parsed time as a vector, and COUNT is the number of
1602 characters from the string left unparsed. This function used to
1603 return the remaining characters as a string.
1605 *** The `gettimeofday' function has replaced the old `time+ticks' function.
1606 The return value is now (SECONDS . MICROSECONDS); the fractional
1607 component is no longer expressed in "ticks".
1609 *** The `ticks/sec' constant has been removed, in light of the above change.
1611 * Changes to the gh_ interface
1613 ** gh_eval_str() now returns an SCM object which is the result of the
1616 ** gh_scm2str() now copies the Scheme data to a caller-provided C
1619 ** gh_scm2newstr() now makes a C array, copies the Scheme data to it,
1620 and returns the array
1622 ** gh_scm2str0() is gone: there is no need to distinguish
1623 null-terminated from non-null-terminated, since gh_scm2newstr() allows
1624 the user to interpret the data both ways.
1626 * Changes to the scm_ interface
1628 ** The new function scm_symbol_value0 provides an easy way to get a
1629 symbol's value from C code:
1631 SCM scm_symbol_value0 (char *NAME)
1632 Return the value of the symbol named by the null-terminated string
1633 NAME in the current module. If the symbol named NAME is unbound in
1634 the current module, return SCM_UNDEFINED.
1636 ** The new function scm_sysintern0 creates new top-level variables,
1637 without assigning them a value.
1639 SCM scm_sysintern0 (char *NAME)
1640 Create a new Scheme top-level variable named NAME. NAME is a
1641 null-terminated string. Return the variable's value cell.
1643 ** The function scm_internal_catch is the guts of catch. It handles
1644 all the mechanics of setting up a catch target, invoking the catch
1645 body, and perhaps invoking the handler if the body does a throw.
1647 The function is designed to be usable from C code, but is general
1648 enough to implement all the semantics Guile Scheme expects from throw.
1650 TAG is the catch tag. Typically, this is a symbol, but this function
1651 doesn't actually care about that.
1653 BODY is a pointer to a C function which runs the body of the catch;
1654 this is the code you can throw from. We call it like this:
1655 BODY (BODY_DATA, JMPBUF)
1657 BODY_DATA is just the BODY_DATA argument we received; we pass it
1658 through to BODY as its first argument. The caller can make
1659 BODY_DATA point to anything useful that BODY might need.
1660 JMPBUF is the Scheme jmpbuf object corresponding to this catch,
1661 which we have just created and initialized.
1663 HANDLER is a pointer to a C function to deal with a throw to TAG,
1664 should one occur. We call it like this:
1665 HANDLER (HANDLER_DATA, THROWN_TAG, THROW_ARGS)
1667 HANDLER_DATA is the HANDLER_DATA argument we recevied; it's the
1668 same idea as BODY_DATA above.
1669 THROWN_TAG is the tag that the user threw to; usually this is
1670 TAG, but it could be something else if TAG was #t (i.e., a
1671 catch-all), or the user threw to a jmpbuf.
1672 THROW_ARGS is the list of arguments the user passed to the THROW
1675 BODY_DATA is just a pointer we pass through to BODY. HANDLER_DATA
1676 is just a pointer we pass through to HANDLER. We don't actually
1677 use either of those pointers otherwise ourselves. The idea is
1678 that, if our caller wants to communicate something to BODY or
1679 HANDLER, it can pass a pointer to it as MUMBLE_DATA, which BODY and
1680 HANDLER can then use. Think of it as a way to make BODY and
1681 HANDLER closures, not just functions; MUMBLE_DATA points to the
1684 Of course, it's up to the caller to make sure that any data a
1685 MUMBLE_DATA needs is protected from GC. A common way to do this is
1686 to make MUMBLE_DATA a pointer to data stored in an automatic
1687 structure variable; since the collector must scan the stack for
1688 references anyway, this assures that any references in MUMBLE_DATA
1691 ** The new function scm_internal_lazy_catch is exactly like
1692 scm_internal_catch, except:
1694 - It does not unwind the stack (this is the major difference).
1695 - If handler returns, its value is returned from the throw.
1696 - BODY always receives #f as its JMPBUF argument (since there's no
1697 jmpbuf associated with a lazy catch, because we don't unwind the
1700 ** scm_body_thunk is a new body function you can pass to
1701 scm_internal_catch if you want the body to be like Scheme's `catch'
1702 --- a thunk, or a function of one argument if the tag is #f.
1704 BODY_DATA is a pointer to a scm_body_thunk_data structure, which
1705 contains the Scheme procedure to invoke as the body, and the tag
1706 we're catching. If the tag is #f, then we pass JMPBUF (created by
1707 scm_internal_catch) to the body procedure; otherwise, the body gets
1710 ** scm_handle_by_proc is a new handler function you can pass to
1711 scm_internal_catch if you want the handler to act like Scheme's catch
1712 --- call a procedure with the tag and the throw arguments.
1714 If the user does a throw to this catch, this function runs a handler
1715 procedure written in Scheme. HANDLER_DATA is a pointer to an SCM
1716 variable holding the Scheme procedure object to invoke. It ought to
1717 be a pointer to an automatic variable (i.e., one living on the stack),
1718 or the procedure object should be otherwise protected from GC.
1720 ** scm_handle_by_message is a new handler function to use with
1721 `scm_internal_catch' if you want Guile to print a message and die.
1722 It's useful for dealing with throws to uncaught keys at the top level.
1724 HANDLER_DATA, if non-zero, is assumed to be a char * pointing to a
1725 message header to print; if zero, we use "guile" instead. That
1726 text is followed by a colon, then the message described by ARGS.
1728 ** The return type of scm_boot_guile is now void; the function does
1729 not return a value, and indeed, never returns at all.
1731 ** The new function scm_shell makes it easy for user applications to
1732 process command-line arguments in a way that is compatible with the
1733 stand-alone guile interpreter (which is in turn compatible with SCSH,
1736 To use the scm_shell function, first initialize any guile modules
1737 linked into your application, and then call scm_shell with the values
1738 of ARGC and ARGV your `main' function received. scm_shell will add
1739 any SCSH-style meta-arguments from the top of the script file to the
1740 argument vector, and then process the command-line arguments. This
1741 generally means loading a script file or starting up an interactive
1742 command interpreter. For details, see "Changes to the stand-alone
1745 ** The new functions scm_get_meta_args and scm_count_argv help you
1746 implement the SCSH-style meta-argument, `\'.
1748 char **scm_get_meta_args (int ARGC, char **ARGV)
1749 If the second element of ARGV is a string consisting of a single
1750 backslash character (i.e. "\\" in Scheme notation), open the file
1751 named by the following argument, parse arguments from it, and return
1752 the spliced command line. The returned array is terminated by a
1755 For details of argument parsing, see above, under "guile now accepts
1756 command-line arguments compatible with SCSH..."
1758 int scm_count_argv (char **ARGV)
1759 Count the arguments in ARGV, assuming it is terminated by a null
1762 For an example of how these functions might be used, see the source
1763 code for the function scm_shell in libguile/script.c.
1765 You will usually want to use scm_shell instead of calling this
1768 ** The new function scm_compile_shell_switches turns an array of
1769 command-line arguments into Scheme code to carry out the actions they
1770 describe. Given ARGC and ARGV, it returns a Scheme expression to
1771 evaluate, and calls scm_set_program_arguments to make any remaining
1772 command-line arguments available to the Scheme code. For example,
1773 given the following arguments:
1775 -e main -s ekko a speckled gecko
1777 scm_set_program_arguments will return the following expression:
1779 (begin (load "ekko") (main (command-line)) (quit))
1781 You will usually want to use scm_shell instead of calling this
1784 ** The function scm_shell_usage prints a usage message appropriate for
1785 an interpreter that uses scm_compile_shell_switches to handle its
1786 command-line arguments.
1788 void scm_shell_usage (int FATAL, char *MESSAGE)
1789 Print a usage message to the standard error output. If MESSAGE is
1790 non-zero, write it before the usage message, followed by a newline.
1791 If FATAL is non-zero, exit the process, using FATAL as the
1792 termination status. (If you want to be compatible with Guile,
1793 always use 1 as the exit status when terminating due to command-line
1796 You will usually want to use scm_shell instead of calling this
1799 ** scm_eval_0str now returns SCM_UNSPECIFIED if the string contains no
1800 expressions. It used to return SCM_EOL. Earth-shattering.
1802 ** The macros for declaring scheme objects in C code have been
1803 rearranged slightly. They are now:
1805 SCM_SYMBOL (C_NAME, SCHEME_NAME)
1806 Declare a static SCM variable named C_NAME, and initialize it to
1807 point to the Scheme symbol whose name is SCHEME_NAME. C_NAME should
1808 be a C identifier, and SCHEME_NAME should be a C string.
1810 SCM_GLOBAL_SYMBOL (C_NAME, SCHEME_NAME)
1811 Just like SCM_SYMBOL, but make C_NAME globally visible.
1813 SCM_VCELL (C_NAME, SCHEME_NAME)
1814 Create a global variable at the Scheme level named SCHEME_NAME.
1815 Declare a static SCM variable named C_NAME, and initialize it to
1816 point to the Scheme variable's value cell.
1818 SCM_GLOBAL_VCELL (C_NAME, SCHEME_NAME)
1819 Just like SCM_VCELL, but make C_NAME globally visible.
1821 The `guile-snarf' script writes initialization code for these macros
1822 to its standard output, given C source code as input.
1824 The SCM_GLOBAL macro is gone.
1826 ** The scm_read_line and scm_read_line_x functions have been replaced
1827 by Scheme code based on the %read-delimited! procedure (known to C
1828 code as scm_read_delimited_x). See its description above for more
1831 ** The function scm_sys_open has been renamed to scm_open. It now
1832 returns a port instead of an FD object.
1834 * The dynamic linking support has changed. For more information, see
1835 libguile/DYNAMIC-LINKING.
1840 User-visible changes from Thursday, September 5, 1996 until Guile 1.0
1843 * Changes to the 'guile' program:
1845 ** Guile now loads some new files when it starts up. Guile first
1846 searches the load path for init.scm, and loads it if found. Then, if
1847 Guile is not being used to execute a script, and the user's home
1848 directory contains a file named `.guile', Guile loads that.
1850 ** You can now use Guile as a shell script interpreter.
1852 To paraphrase the SCSH manual:
1854 When Unix tries to execute an executable file whose first two
1855 characters are the `#!', it treats the file not as machine code to
1856 be directly executed by the native processor, but as source code
1857 to be executed by some interpreter. The interpreter to use is
1858 specified immediately after the #! sequence on the first line of
1859 the source file. The kernel reads in the name of the interpreter,
1860 and executes that instead. It passes the interpreter the source
1861 filename as its first argument, with the original arguments
1862 following. Consult the Unix man page for the `exec' system call
1863 for more information.
1865 Now you can use Guile as an interpreter, using a mechanism which is a
1866 compatible subset of that provided by SCSH.
1868 Guile now recognizes a '-s' command line switch, whose argument is the
1869 name of a file of Scheme code to load. It also treats the two
1870 characters `#!' as the start of a comment, terminated by `!#'. Thus,
1871 to make a file of Scheme code directly executable by Unix, insert the
1872 following two lines at the top of the file:
1874 #!/usr/local/bin/guile -s
1877 Guile treats the argument of the `-s' command-line switch as the name
1878 of a file of Scheme code to load, and treats the sequence `#!' as the
1879 start of a block comment, terminated by `!#'.
1881 For example, here's a version of 'echo' written in Scheme:
1883 #!/usr/local/bin/guile -s
1885 (let loop ((args (cdr (program-arguments))))
1888 (display (car args))
1889 (if (pair? (cdr args))
1891 (loop (cdr args)))))
1894 Why does `#!' start a block comment terminated by `!#', instead of the
1895 end of the line? That is the notation SCSH uses, and although we
1896 don't yet support the other SCSH features that motivate that choice,
1897 we would like to be backward-compatible with any existing Guile
1898 scripts once we do. Furthermore, if the path to Guile on your system
1899 is too long for your kernel, you can start the script with this
1903 exec /really/long/path/to/guile -s "$0" ${1+"$@"}
1906 Note that some very old Unix systems don't support the `#!' syntax.
1909 ** You can now run Guile without installing it.
1911 Previous versions of the interactive Guile interpreter (`guile')
1912 couldn't start up unless Guile's Scheme library had been installed;
1913 they used the value of the environment variable `SCHEME_LOAD_PATH'
1914 later on in the startup process, but not to find the startup code
1915 itself. Now Guile uses `SCHEME_LOAD_PATH' in all searches for Scheme
1918 To run Guile without installing it, build it in the normal way, and
1919 then set the environment variable `SCHEME_LOAD_PATH' to a
1920 colon-separated list of directories, including the top-level directory
1921 of the Guile sources. For example, if you unpacked Guile so that the
1922 full filename of this NEWS file is /home/jimb/guile-1.0b3/NEWS, then
1925 export SCHEME_LOAD_PATH=/home/jimb/my-scheme:/home/jimb/guile-1.0b3
1928 ** Guile's read-eval-print loop no longer prints #<unspecified>
1929 results. If the user wants to see this, she can evaluate the
1930 expression (assert-repl-print-unspecified #t), perhaps in her startup
1933 ** Guile no longer shows backtraces by default when an error occurs;
1934 however, it does display a message saying how to get one, and how to
1935 request that they be displayed by default. After an error, evaluate
1937 to see a backtrace, and
1938 (debug-enable 'backtrace)
1939 to see them by default.
1943 * Changes to Guile Scheme:
1945 ** Guile now distinguishes between #f and the empty list.
1947 This is for compatibility with the IEEE standard, the (possibly)
1948 upcoming Revised^5 Report on Scheme, and many extant Scheme
1951 Guile used to have #f and '() denote the same object, to make Scheme's
1952 type system more compatible with Emacs Lisp's. However, the change
1953 caused too much trouble for Scheme programmers, and we found another
1954 way to reconcile Emacs Lisp with Scheme that didn't require this.
1957 ** Guile's delq, delv, delete functions, and their destructive
1958 counterparts, delq!, delv!, and delete!, now remove all matching
1959 elements from the list, not just the first. This matches the behavior
1960 of the corresponding Emacs Lisp functions, and (I believe) the Maclisp
1961 functions which inspired them.
1963 I recognize that this change may break code in subtle ways, but it
1964 seems best to make the change before the FSF's first Guile release,
1968 ** The compiled-library-path function has been deleted from libguile.
1970 ** The facilities for loading Scheme source files have changed.
1972 *** The variable %load-path now tells Guile which directories to search
1973 for Scheme code. Its value is a list of strings, each of which names
1976 *** The variable %load-extensions now tells Guile which extensions to
1977 try appending to a filename when searching the load path. Its value
1978 is a list of strings. Its default value is ("" ".scm").
1980 *** (%search-load-path FILENAME) searches the directories listed in the
1981 value of the %load-path variable for a Scheme file named FILENAME,
1982 with all the extensions listed in %load-extensions. If it finds a
1983 match, then it returns its full filename. If FILENAME is absolute, it
1984 returns it unchanged. Otherwise, it returns #f.
1986 %search-load-path will not return matches that refer to directories.
1988 *** (primitive-load FILENAME :optional CASE-INSENSITIVE-P SHARP)
1989 uses %seach-load-path to find a file named FILENAME, and loads it if
1990 it finds it. If it can't read FILENAME for any reason, it throws an
1993 The arguments CASE-INSENSITIVE-P and SHARP are interpreted as by the
1996 *** load uses the same searching semantics as primitive-load.
1998 *** The functions %try-load, try-load-with-path, %load, load-with-path,
1999 basic-try-load-with-path, basic-load-with-path, try-load-module-with-
2000 path, and load-module-with-path have been deleted. The functions
2001 above should serve their purposes.
2003 *** If the value of the variable %load-hook is a procedure,
2004 `primitive-load' applies its value to the name of the file being
2005 loaded (without the load path directory name prepended). If its value
2006 is #f, it is ignored. Otherwise, an error occurs.
2008 This is mostly useful for printing load notification messages.
2011 ** The function `eval!' is no longer accessible from the scheme level.
2012 We can't allow operations which introduce glocs into the scheme level,
2013 because Guile's type system can't handle these as data. Use `eval' or
2014 `read-and-eval!' (see below) as replacement.
2016 ** The new function read-and-eval! reads an expression from PORT,
2017 evaluates it, and returns the result. This is more efficient than
2018 simply calling `read' and `eval', since it is not necessary to make a
2019 copy of the expression for the evaluator to munge.
2021 Its optional arguments CASE_INSENSITIVE_P and SHARP are interpreted as
2022 for the `read' function.
2025 ** The function `int?' has been removed; its definition was identical
2026 to that of `integer?'.
2028 ** The functions `<?', `<?', `<=?', `=?', `>?', and `>=?'. Code should
2029 use the R4RS names for these functions.
2031 ** The function object-properties no longer returns the hash handle;
2032 it simply returns the object's property list.
2034 ** Many functions have been changed to throw errors, instead of
2035 returning #f on failure. The point of providing exception handling in
2036 the language is to simplify the logic of user code, but this is less
2037 useful if Guile's primitives don't throw exceptions.
2039 ** The function `fileno' has been renamed from `%fileno'.
2041 ** The function primitive-mode->fdes returns #t or #f now, not 1 or 0.
2044 * Changes to Guile's C interface:
2046 ** The library's initialization procedure has been simplified.
2047 scm_boot_guile now has the prototype:
2049 void scm_boot_guile (int ARGC,
2051 void (*main_func) (),
2054 scm_boot_guile calls MAIN_FUNC, passing it CLOSURE, ARGC, and ARGV.
2055 MAIN_FUNC should do all the work of the program (initializing other
2056 packages, reading user input, etc.) before returning. When MAIN_FUNC
2057 returns, call exit (0); this function never returns. If you want some
2058 other exit value, MAIN_FUNC may call exit itself.
2060 scm_boot_guile arranges for program-arguments to return the strings
2061 given by ARGC and ARGV. If MAIN_FUNC modifies ARGC/ARGV, should call
2062 scm_set_program_arguments with the final list, so Scheme code will
2063 know which arguments have been processed.
2065 scm_boot_guile establishes a catch-all catch handler which prints an
2066 error message and exits the process. This means that Guile exits in a
2067 coherent way when system errors occur and the user isn't prepared to
2068 handle it. If the user doesn't like this behavior, they can establish
2069 their own universal catcher in MAIN_FUNC to shadow this one.
2071 Why must the caller do all the real work from MAIN_FUNC? The garbage
2072 collector assumes that all local variables of type SCM will be above
2073 scm_boot_guile's stack frame on the stack. If you try to manipulate
2074 SCM values after this function returns, it's the luck of the draw
2075 whether the GC will be able to find the objects you allocate. So,
2076 scm_boot_guile function exits, rather than returning, to discourage
2077 people from making that mistake.
2079 The IN, OUT, and ERR arguments were removed; there are other
2080 convenient ways to override these when desired.
2082 The RESULT argument was deleted; this function should never return.
2084 The BOOT_CMD argument was deleted; the MAIN_FUNC argument is more
2088 ** Guile's header files should no longer conflict with your system's
2091 In order to compile code which #included <libguile.h>, previous
2092 versions of Guile required you to add a directory containing all the
2093 Guile header files to your #include path. This was a problem, since
2094 Guile's header files have names which conflict with many systems'
2097 Now only <libguile.h> need appear in your #include path; you must
2098 refer to all Guile's other header files as <libguile/mumble.h>.
2099 Guile's installation procedure puts libguile.h in $(includedir), and
2100 the rest in $(includedir)/libguile.
2103 ** Two new C functions, scm_protect_object and scm_unprotect_object,
2104 have been added to the Guile library.
2106 scm_protect_object (OBJ) protects OBJ from the garbage collector.
2107 OBJ will not be freed, even if all other references are dropped,
2108 until someone does scm_unprotect_object (OBJ). Both functions
2111 Note that calls to scm_protect_object do not nest. You can call
2112 scm_protect_object any number of times on a given object, and the
2113 next call to scm_unprotect_object will unprotect it completely.
2115 Basically, scm_protect_object and scm_unprotect_object just
2116 maintain a list of references to things. Since the GC knows about
2117 this list, all objects it mentions stay alive. scm_protect_object
2118 adds its argument to the list; scm_unprotect_object remove its
2119 argument from the list.
2122 ** scm_eval_0str now returns the value of the last expression
2125 ** The new function scm_read_0str reads an s-expression from a
2126 null-terminated string, and returns it.
2128 ** The new function `scm_stdio_to_port' converts a STDIO file pointer
2129 to a Scheme port object.
2131 ** The new function `scm_set_program_arguments' allows C code to set
2132 the value teruturned by the Scheme `program-arguments' function.
2137 * Guile no longer includes sophisticated Tcl/Tk support.
2139 The old Tcl/Tk support was unsatisfying to us, because it required the
2140 user to link against the Tcl library, as well as Tk and Guile. The
2141 interface was also un-lispy, in that it preserved Tcl/Tk's practice of
2142 referring to widgets by names, rather than exporting widgets to Scheme
2143 code as a special datatype.
2145 In the Usenix Tk Developer's Workshop held in July 1996, the Tcl/Tk
2146 maintainers described some very interesting changes in progress to the
2147 Tcl/Tk internals, which would facilitate clean interfaces between lone
2148 Tk and other interpreters --- even for garbage-collected languages
2149 like Scheme. They expected the new Tk to be publicly available in the
2152 Since it seems that Guile might soon have a new, cleaner interface to
2153 lone Tk, and that the old Guile/Tk glue code would probably need to be
2154 completely rewritten, we (Jim Blandy and Richard Stallman) have
2155 decided not to support the old code. We'll spend the time instead on
2156 a good interface to the newer Tk, as soon as it is available.
2158 Until then, gtcltk-lib provides trivial, low-maintenance functionality.
2161 Copyright information:
2163 Copyright (C) 1996,1997 Free Software Foundation, Inc.
2165 Permission is granted to anyone to make or distribute verbatim copies
2166 of this document as received, in any medium, provided that the
2167 copyright notice and this permission notice are preserved,
2168 thus giving the recipient permission to redistribute in turn.
2170 Permission is granted to distribute modified versions
2171 of this document, or of portions of it,
2172 under the above conditions, provided also that they
2173 carry prominent notices stating who last changed them.
2178 paragraph-separate: "[
\f]*$"