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@prep.ai.mit.edu.
9 [[trim out any sections we don't need]]
11 * Changes to the distribution
13 ** Nightly snapshots are now available from ftp.red-bean.com.
14 The old server, ftp.cyclic.com, has been relinquished to its rightful
17 Nightly snapshots of the Guile development sources are now available via
18 anonymous FTP from ftp.red-bean.com, as /pub/guile/guile-snap.tar.gz.
20 Via the web, that's: ftp://ftp.red-bean.com/pub/guile/guile-snap.tar.gz
21 For getit, that's: ftp.red-bean.com:/pub/guile/guile-snap.tar.gz
23 * Changes to the procedure for linking libguile with your programs
25 ** Like Guile 1.1, Guile 1.2 will now use the Rx regular expression
26 library, if it is installed on your system. When you are linking
27 libguile into your own programs, this means you will have to link
28 against -lguile, -lqt (if you configured Guile with thread support),
31 If you are using autoconf to generate configuration scripts for your
32 application, the following lines should suffice to add the appropriate
33 libraries to your link command:
35 ### Find Rx, quickthreads and libguile.
36 AC_CHECK_LIB(rx, main)
37 AC_CHECK_LIB(qt, main)
38 AC_CHECK_LIB(guile, scm_shell)
40 * Changes to Scheme functions and syntax
42 ** The #/ syntax for module names is depreciated, and will be removed
43 in a future version of Guile. Instead of
51 The latter syntax is more consistent with existing Lisp practice.
53 ** Guile now does fancier printing of structures. Structures are the
54 underlying implementation for records, which in turn are used to
55 implement modules, so all of these object now print differently and in
56 a more informative way.
58 The Scheme printer will examine the builtin variable
59 *struct-printer* whenever it needs to print a structure object. When
60 this variable is not `#f' it is deemed to be a procedure and will be
61 applied to the structure object and the output port. When
62 *struct-printer* is `#f' or the procedure return `#f' the structure
63 object will be printed in the boring #<struct 80458270> form.
65 This hook is used by some routines in ice-9/boot-9.scm to implement
66 type specific printing routines. Please read the comments there about
69 One of the more specific uses of structs are records. The printing
70 procedure that could be passed to MAKE-RECORD-TYPE is now actually
71 called. It should behave like a *struct-printer* procedure (described
74 ** Guile now supports a new R4RS-compliant syntax for keywords. A
75 token of the form #:NAME, where NAME has the same syntax as a Scheme
76 symbol, is the external representation of the keyword named NAME.
77 Keyword objects print using this syntax as well, so values containing
78 keyword objects can be read back into Guile. When used in an
79 expression, keywords are self-quoting objects.
81 Guile suports this read syntax, and uses this print syntax, regardless
82 of the current setting of the `keyword' read option. The `keyword'
83 read option only controls whether Guile recognizes the `:NAME' syntax,
84 which is incompatible with R4RS. (R4RS says such token represent
87 ** Guile has regular expression support again. Guile 1.0 included
88 functions for matching regular expressions, based on the Rx library.
89 In Guile 1.1, the Guile/Rx interface was removed to simplify the
90 distribution, and thus Guile had no regular expression support. Guile
91 1.2 now adds back the most commonly used functions, and supports all
92 of SCSH's regular expression functions. They are:
94 *** [[get docs from Tim?]]
96 * Changes to the gh_ interface
98 * Changes to the scm_ interface
100 * Changes to system call interfaces:
102 ** The value returned by `raise' is now unspecified. It throws an exception
105 ** A new procedure `sigaction' can be used to install signal handlers
107 (sigaction signum [action] [flags])
109 signum is the signal number, which can be specified using the value
112 If action is omitted, sigaction returns a pair: the CAR is the current
113 signal hander, which will be either an integer with the value SIG_DFL
114 (default action) or SIG_IGN (ignore), or the Scheme procedure which
115 handles the signal, or #f if a non-Scheme procedure handles the
116 signal. The CDR contains the current sigaction flags for the handler.
118 If action is provided, it is installed as the new handler for signum.
119 action can be a Scheme procedure taking one argument, or the value of
120 SIG_DFL (default action) or SIG_IGN (ignore), or #f to restore
121 whatever signal handler was installed before sigaction was first used.
122 Flags can optionally be specified for the new handler (SA_RESTART is
123 always used if the system provides it, so need not be specified.) The
124 return value is a pair with information about the old handler as
127 This interface does not provide access to the "signal blocking"
128 facility. Maybe this is not needed, since the thread support may
129 provide solutions to the problem of consistent access to data
133 Changes in Guile 1.1 (Fri May 16 1997):
135 * Changes to the distribution.
137 The Guile 1.0 distribution has been split up into several smaller
139 guile-core --- the Guile interpreter itself.
140 guile-tcltk --- the interface between the Guile interpreter and
141 Tcl/Tk; Tcl is an interpreter for a stringy language, and Tk
142 is a toolkit for building graphical user interfaces.
143 guile-rgx-ctax --- the interface between Guile and the Rx regular
144 expression matcher, and the translator for the Ctax
145 programming language. These are packaged together because the
146 Ctax translator uses Rx to parse Ctax source code.
148 This NEWS file describes the changes made to guile-core since the 1.0
151 We no longer distribute the documentation, since it was either out of
152 date, or incomplete. As soon as we have current documentation, we
155 * Changes to the stand-alone interpreter
157 ** guile now accepts command-line arguments compatible with SCSH, Olin
158 Shivers' Scheme Shell.
160 In general, arguments are evaluated from left to right, but there are
161 exceptions. The following switches stop argument processing, and
162 stash all remaining command-line arguments as the value returned by
163 the (command-line) function.
164 -s SCRIPT load Scheme source code from FILE, and exit
165 -c EXPR evalute Scheme expression EXPR, and exit
166 -- stop scanning arguments; run interactively
168 The switches below are processed as they are encountered.
169 -l FILE load Scheme source code from FILE
170 -e FUNCTION after reading script, apply FUNCTION to
171 command line arguments
172 -ds do -s script at this point
173 --emacs enable Emacs protocol (experimental)
174 -h, --help display this help and exit
175 -v, --version display version information and exit
176 \ read arguments from following script lines
178 So, for example, here is a Guile script named `ekko' (thanks, Olin)
179 which re-implements the traditional "echo" command:
181 #!/usr/local/bin/guile -s
184 (map (lambda (arg) (display arg) (display " "))
188 (main (command-line))
190 Suppose we invoke this script as follows:
192 ekko a speckled gecko
194 Through the magic of Unix script processing (triggered by the `#!'
195 token at the top of the file), /usr/local/bin/guile receives the
196 following list of command-line arguments:
198 ("-s" "./ekko" "a" "speckled" "gecko")
200 Unix inserts the name of the script after the argument specified on
201 the first line of the file (in this case, "-s"), and then follows that
202 with the arguments given to the script. Guile loads the script, which
203 defines the `main' function, and then applies it to the list of
204 remaining command-line arguments, ("a" "speckled" "gecko").
206 In Unix, the first line of a script file must take the following form:
208 #!INTERPRETER ARGUMENT
210 where INTERPRETER is the absolute filename of the interpreter
211 executable, and ARGUMENT is a single command-line argument to pass to
214 You may only pass one argument to the interpreter, and its length is
215 limited. These restrictions can be annoying to work around, so Guile
216 provides a general mechanism (borrowed from, and compatible with,
217 SCSH) for circumventing them.
219 If the ARGUMENT in a Guile script is a single backslash character,
220 `\', Guile will open the script file, parse arguments from its second
221 and subsequent lines, and replace the `\' with them. So, for example,
222 here is another implementation of the `ekko' script:
224 #!/usr/local/bin/guile \
228 (for-each (lambda (arg) (display arg) (display " "))
232 If the user invokes this script as follows:
234 ekko a speckled gecko
236 Unix expands this into
238 /usr/local/bin/guile \ ekko a speckled gecko
240 When Guile sees the `\' argument, it replaces it with the arguments
241 read from the second line of the script, producing:
243 /usr/local/bin/guile -e main -s ekko a speckled gecko
245 This tells Guile to load the `ekko' script, and apply the function
246 `main' to the argument list ("a" "speckled" "gecko").
248 Here is how Guile parses the command-line arguments:
249 - Each space character terminates an argument. This means that two
250 spaces in a row introduce an empty-string argument.
251 - The tab character is not permitted (unless you quote it with the
252 backslash character, as described below), to avoid confusion.
253 - The newline character terminates the sequence of arguments, and will
254 also terminate a final non-empty argument. (However, a newline
255 following a space will not introduce a final empty-string argument;
256 it only terminates the argument list.)
257 - The backslash character is the escape character. It escapes
258 backslash, space, tab, and newline. The ANSI C escape sequences
259 like \n and \t are also supported. These produce argument
260 constituents; the two-character combination \n doesn't act like a
261 terminating newline. The escape sequence \NNN for exactly three
262 octal digits reads as the character whose ASCII code is NNN. As
263 above, characters produced this way are argument constituents.
264 Backslash followed by other characters is not allowed.
266 * Changes to the procedure for linking libguile with your programs
268 ** Guile now builds and installs a shared guile library, if your
269 system support shared libraries. (It still builds a static library on
270 all systems.) Guile automatically detects whether your system
271 supports shared libraries. To prevent Guile from buildisg shared
272 libraries, pass the `--disable-shared' flag to the configure script.
274 Guile takes longer to compile when it builds shared libraries, because
275 it must compile every file twice --- once to produce position-
276 independent object code, and once to produce normal object code.
278 ** The libthreads library has been merged into libguile.
280 To link a program against Guile, you now need only link against
281 -lguile and -lqt; -lthreads is no longer needed. If you are using
282 autoconf to generate configuration scripts for your application, the
283 following lines should suffice to add the appropriate libraries to
286 ### Find quickthreads and libguile.
287 AC_CHECK_LIB(qt, main)
288 AC_CHECK_LIB(guile, scm_shell)
290 * Changes to Scheme functions
292 ** Guile Scheme's special syntax for keyword objects is now optional,
293 and disabled by default.
295 The syntax variation from R4RS made it difficult to port some
296 interesting packages to Guile. The routines which accepted keyword
297 arguments (mostly in the module system) have been modified to also
298 accept symbols whose names begin with `:'.
300 To change the keyword syntax, you must first import the (ice-9 debug)
302 (use-modules (ice-9 debug))
304 Then you can enable the keyword syntax as follows:
305 (read-set! keywords 'prefix)
307 To disable keyword syntax, do this:
308 (read-set! keywords #f)
310 ** Many more primitive functions accept shared substrings as
311 arguments. In the past, these functions required normal, mutable
312 strings as arguments, although they never made use of this
315 ** The uniform array functions now operate on byte vectors. These
316 functions are `array-fill!', `serial-array-copy!', `array-copy!',
317 `serial-array-map', `array-map', `array-for-each', and
320 ** The new functions `trace' and `untrace' implement simple debugging
321 support for Scheme functions.
323 The `trace' function accepts any number of procedures as arguments,
324 and tells the Guile interpreter to display each procedure's name and
325 arguments each time the procedure is invoked. When invoked with no
326 arguments, `trace' returns the list of procedures currently being
329 The `untrace' function accepts any number of procedures as arguments,
330 and tells the Guile interpreter not to trace them any more. When
331 invoked with no arguments, `untrace' untraces all curretly traced
334 The tracing in Guile has an advantage over most other systems: we
335 don't create new procedure objects, but mark the procedure objects
336 themselves. This means that anonymous and internal procedures can be
339 ** The function `assert-repl-prompt' has been renamed to
340 `set-repl-prompt!'. It takes one argument, PROMPT.
341 - If PROMPT is #f, the Guile read-eval-print loop will not prompt.
342 - If PROMPT is a string, we use it as a prompt.
343 - If PROMPT is a procedure accepting no arguments, we call it, and
344 display the result as a prompt.
345 - Otherwise, we display "> ".
347 ** The new function `eval-string' reads Scheme expressions from a
348 string and evaluates them, returning the value of the last expression
349 in the string. If the string contains no expressions, it returns an
352 ** The new function `thunk?' returns true iff its argument is a
353 procedure of zero arguments.
355 ** `defined?' is now a builtin function, instead of syntax. This
356 means that its argument should be quoted. It returns #t iff its
357 argument is bound in the current module.
359 ** The new syntax `use-modules' allows you to add new modules to your
360 environment without re-typing a complete `define-module' form. It
361 accepts any number of module names as arguments, and imports their
362 public bindings into the current module.
364 ** The new function (module-defined? NAME MODULE) returns true iff
365 NAME, a symbol, is defined in MODULE, a module object.
367 ** The new function `builtin-bindings' creates and returns a hash
368 table containing copies of all the root module's bindings.
370 ** The new function `builtin-weak-bindings' does the same as
371 `builtin-bindings', but creates a doubly-weak hash table.
373 ** The `equal?' function now considers variable objects to be
374 equivalent if they have the same name and the same value.
376 ** The new function `command-line' returns the command-line arguments
377 given to Guile, as a list of strings.
379 When using guile as a script interpreter, `command-line' returns the
380 script's arguments; those processed by the interpreter (like `-s' or
381 `-c') are omitted. (In other words, you get the normal, expected
382 behavior.) Any application that uses scm_shell to process its
383 command-line arguments gets this behavior as well.
385 ** The new function `load-user-init' looks for a file called `.guile'
386 in the user's home directory, and loads it if it exists. This is
387 mostly for use by the code generated by scm_compile_shell_switches,
388 but we thought it might also be useful in other circumstances.
390 ** The new function `log10' returns the base-10 logarithm of its
393 ** Changes to I/O functions
395 *** The functions `read', `primitive-load', `read-and-eval!', and
396 `primitive-load-path' no longer take optional arguments controlling
397 case insensitivity and a `#' parser.
399 Case sensitivity is now controlled by a read option called
400 `case-insensitive'. The user can add new `#' syntaxes with the
401 `read-hash-extend' function (see below).
403 *** The new function `read-hash-extend' allows the user to change the
404 syntax of Guile Scheme in a somewhat controlled way.
406 (read-hash-extend CHAR PROC)
407 When parsing S-expressions, if we read a `#' character followed by
408 the character CHAR, use PROC to parse an object from the stream.
409 If PROC is #f, remove any parsing procedure registered for CHAR.
411 The reader applies PROC to two arguments: CHAR and an input port.
413 *** The new functions read-delimited and read-delimited! provide a
414 general mechanism for doing delimited input on streams.
416 (read-delimited DELIMS [PORT HANDLE-DELIM])
417 Read until we encounter one of the characters in DELIMS (a string),
418 or end-of-file. PORT is the input port to read from; it defaults to
419 the current input port. The HANDLE-DELIM parameter determines how
420 the terminating character is handled; it should be one of the
423 'trim omit delimiter from result
424 'peek leave delimiter character in input stream
425 'concat append delimiter character to returned value
426 'split return a pair: (RESULT . TERMINATOR)
428 HANDLE-DELIM defaults to 'peek.
430 (read-delimited! DELIMS BUF [PORT HANDLE-DELIM START END])
431 A side-effecting variant of `read-delimited'.
433 The data is written into the string BUF at the indices in the
434 half-open interval [START, END); the default interval is the whole
435 string: START = 0 and END = (string-length BUF). The values of
436 START and END must specify a well-defined interval in BUF, i.e.
437 0 <= START <= END <= (string-length BUF).
439 It returns NBYTES, the number of bytes read. If the buffer filled
440 up without a delimiter character being found, it returns #f. If the
441 port is at EOF when the read starts, it returns the EOF object.
443 If an integer is returned (i.e., the read is successfully terminated
444 by reading a delimiter character), then the HANDLE-DELIM parameter
445 determines how to handle the terminating character. It is described
446 above, and defaults to 'peek.
448 (The descriptions of these functions were borrowed from the SCSH
449 manual, by Olin Shivers and Brian Carlstrom.)
451 *** The `%read-delimited!' function is the primitive used to implement
452 `read-delimited' and `read-delimited!'.
454 (%read-delimited! DELIMS BUF GOBBLE? [PORT START END])
456 This returns a pair of values: (TERMINATOR . NUM-READ).
457 - TERMINATOR describes why the read was terminated. If it is a
458 character or the eof object, then that is the value that terminated
459 the read. If it is #f, the function filled the buffer without finding
460 a delimiting character.
461 - NUM-READ is the number of characters read into BUF.
463 If the read is successfully terminated by reading a delimiter
464 character, then the gobble? parameter determines what to do with the
465 terminating character. If true, the character is removed from the
466 input stream; if false, the character is left in the input stream
467 where a subsequent read operation will retrieve it. In either case,
468 the character is also the first value returned by the procedure call.
470 (The descriptions of this function was borrowed from the SCSH manual,
471 by Olin Shivers and Brian Carlstrom.)
473 *** The `read-line' and `read-line!' functions have changed; they now
474 trim the terminator by default; previously they appended it to the
475 returned string. For the old behavior, use (read-line PORT 'concat).
477 *** The functions `uniform-array-read!' and `uniform-array-write!' now
478 take new optional START and END arguments, specifying the region of
479 the array to read and write.
481 *** The `ungetc-char-ready?' function has been removed. We feel it's
482 inappropriate for an interface to expose implementation details this
485 ** Changes to the Unix library and system call interface
487 *** The new fcntl function provides access to the Unix `fcntl' system
490 (fcntl PORT COMMAND VALUE)
491 Apply COMMAND to PORT's file descriptor, with VALUE as an argument.
492 Values for COMMAND are:
494 F_DUPFD duplicate a file descriptor
495 F_GETFD read the descriptor's close-on-exec flag
496 F_SETFD set the descriptor's close-on-exec flag to VALUE
497 F_GETFL read the descriptor's flags, as set on open
498 F_SETFL set the descriptor's flags, as set on open to VALUE
499 F_GETOWN return the process ID of a socket's owner, for SIGIO
500 F_SETOWN set the process that owns a socket to VALUE, for SIGIO
501 FD_CLOEXEC not sure what this is
503 For details, see the documentation for the fcntl system call.
505 *** The arguments to `select' have changed, for compatibility with
506 SCSH. The TIMEOUT parameter may now be non-integral, yielding the
507 expected behavior. The MILLISECONDS parameter has been changed to
508 MICROSECONDS, to more closely resemble the underlying system call.
509 The RVEC, WVEC, and EVEC arguments can now be vectors; the type of the
510 corresponding return set will be the same.
512 *** The arguments to the `mknod' system call have changed. They are
515 (mknod PATH TYPE PERMS DEV)
516 Create a new file (`node') in the file system. PATH is the name of
517 the file to create. TYPE is the kind of file to create; it should
518 be 'fifo, 'block-special, or 'char-special. PERMS specifies the
519 permission bits to give the newly created file. If TYPE is
520 'block-special or 'char-special, DEV specifies which device the
521 special file refers to; its interpretation depends on the kind of
522 special file being created.
524 *** The `fork' function has been renamed to `primitive-fork', to avoid
525 clashing with various SCSH forks.
527 *** The `recv' and `recvfrom' functions have been renamed to `recv!'
528 and `recvfrom!'. They no longer accept a size for a second argument;
529 you must pass a string to hold the received value. They no longer
530 return the buffer. Instead, `recv' returns the length of the message
531 received, and `recvfrom' returns a pair containing the packet's length
532 and originating address.
534 *** The file descriptor datatype has been removed, as have the
535 `read-fd', `write-fd', `close', `lseek', and `dup' functions.
536 We plan to replace these functions with a SCSH-compatible interface.
538 *** The `create' function has been removed; it's just a special case
541 *** There are new functions to break down process termination status
542 values. In the descriptions below, STATUS is a value returned by
545 (status:exit-val STATUS)
546 If the child process exited normally, this function returns the exit
547 code for the child process (i.e., the value passed to exit, or
548 returned from main). If the child process did not exit normally,
549 this function returns #f.
551 (status:stop-sig STATUS)
552 If the child process was suspended by a signal, this function
553 returns the signal that suspended the child. Otherwise, it returns
556 (status:term-sig STATUS)
557 If the child process terminated abnormally, this function returns
558 the signal that terminated the child. Otherwise, this function
561 POSIX promises that exactly one of these functions will return true on
562 a valid STATUS value.
564 These functions are compatible with SCSH.
566 *** There are new accessors and setters for the broken-out time vectors
567 returned by `localtime', `gmtime', and that ilk. They are:
569 Component Accessor Setter
570 ========================= ============ ============
571 seconds tm:sec set-tm:sec
572 minutes tm:min set-tm:min
573 hours tm:hour set-tm:hour
574 day of the month tm:mday set-tm:mday
575 month tm:mon set-tm:mon
576 year tm:year set-tm:year
577 day of the week tm:wday set-tm:wday
578 day in the year tm:yday set-tm:yday
579 daylight saving time tm:isdst set-tm:isdst
580 GMT offset, seconds tm:gmtoff set-tm:gmtoff
581 name of time zone tm:zone set-tm:zone
583 *** There are new accessors for the vectors returned by `uname',
584 describing the host system:
587 ============================================== ================
588 name of the operating system implementation utsname:sysname
589 network name of this machine utsname:nodename
590 release level of the operating system utsname:release
591 version level of the operating system utsname:version
592 machine hardware platform utsname:machine
594 *** There are new accessors for the vectors returned by `getpw',
595 `getpwnam', `getpwuid', and `getpwent', describing entries from the
596 system's user database:
599 ====================== =================
600 user name passwd:name
601 user password passwd:passwd
604 real name passwd:gecos
605 home directory passwd:dir
606 shell program passwd:shell
608 *** There are new accessors for the vectors returned by `getgr',
609 `getgrnam', `getgrgid', and `getgrent', describing entries from the
610 system's group database:
613 ======================= ============
614 group name group:name
615 group password group:passwd
617 group members group:mem
619 *** There are new accessors for the vectors returned by `gethost',
620 `gethostbyaddr', `gethostbyname', and `gethostent', describing
624 ========================= ===============
625 official name of host hostent:name
626 alias list hostent:aliases
627 host address type hostent:addrtype
628 length of address hostent:length
629 list of addresses hostent:addr-list
631 *** There are new accessors for the vectors returned by `getnet',
632 `getnetbyaddr', `getnetbyname', and `getnetent', describing internet
636 ========================= ===============
637 official name of net netent:name
638 alias list netent:aliases
639 net number type netent:addrtype
640 net number netent:net
642 *** There are new accessors for the vectors returned by `getproto',
643 `getprotobyname', `getprotobynumber', and `getprotoent', describing
647 ========================= ===============
648 official protocol name protoent:name
649 alias list protoent:aliases
650 protocol number protoent:proto
652 *** There are new accessors for the vectors returned by `getserv',
653 `getservbyname', `getservbyport', and `getservent', describing
657 ========================= ===============
658 official service name servent:name
659 alias list servent:aliases
660 port number servent:port
661 protocol to use servent:proto
663 *** There are new accessors for the sockaddr structures returned by
664 `accept', `getsockname', `getpeername', `recvfrom!':
667 ======================================== ===============
668 address format (`family') sockaddr:fam
669 path, for file domain addresses sockaddr:path
670 address, for internet domain addresses sockaddr:addr
671 TCP or UDP port, for internet sockaddr:port
673 *** The `getpwent', `getgrent', `gethostent', `getnetent',
674 `getprotoent', and `getservent' functions now return #f at the end of
675 the user database. (They used to throw an exception.)
677 Note that calling MUMBLEent function is equivalent to calling the
678 corresponding MUMBLE function with no arguments.
680 *** The `setpwent', `setgrent', `sethostent', `setnetent',
681 `setprotoent', and `setservent' routines now take no arguments.
683 *** The `gethost', `getproto', `getnet', and `getserv' functions now
684 provide more useful information when they throw an exception.
686 *** The `lnaof' function has been renamed to `inet-lnaof'.
688 *** Guile now claims to have the `current-time' feature.
690 *** The `mktime' function now takes an optional second argument ZONE,
691 giving the time zone to use for the conversion. ZONE should be a
692 string, in the same format as expected for the "TZ" environment variable.
694 *** The `strptime' function now returns a pair (TIME . COUNT), where
695 TIME is the parsed time as a vector, and COUNT is the number of
696 characters from the string left unparsed. This function used to
697 return the remaining characters as a string.
699 *** The `gettimeofday' function has replaced the old `time+ticks' function.
700 The return value is now (SECONDS . MICROSECONDS); the fractional
701 component is no longer expressed in "ticks".
703 *** The `ticks/sec' constant has been removed, in light of the above change.
705 * Changes to the gh_ interface
707 ** gh_eval_str() now returns an SCM object which is the result of the
710 ** gh_scm2str() now copies the Scheme data to a caller-provided C
713 ** gh_scm2newstr() now makes a C array, copies the Scheme data to it,
714 and returns the array
716 ** gh_scm2str0() is gone: there is no need to distinguish
717 null-terminated from non-null-terminated, since gh_scm2newstr() allows
718 the user to interpret the data both ways.
720 * Changes to the scm_ interface
722 ** The new function scm_symbol_value0 provides an easy way to get a
723 symbol's value from C code:
725 SCM scm_symbol_value0 (char *NAME)
726 Return the value of the symbol named by the null-terminated string
727 NAME in the current module. If the symbol named NAME is unbound in
728 the current module, return SCM_UNDEFINED.
730 ** The new function scm_sysintern0 creates new top-level variables,
731 without assigning them a value.
733 SCM scm_sysintern0 (char *NAME)
734 Create a new Scheme top-level variable named NAME. NAME is a
735 null-terminated string. Return the variable's value cell.
737 ** The function scm_internal_catch is the guts of catch. It handles
738 all the mechanics of setting up a catch target, invoking the catch
739 body, and perhaps invoking the handler if the body does a throw.
741 The function is designed to be usable from C code, but is general
742 enough to implement all the semantics Guile Scheme expects from throw.
744 TAG is the catch tag. Typically, this is a symbol, but this function
745 doesn't actually care about that.
747 BODY is a pointer to a C function which runs the body of the catch;
748 this is the code you can throw from. We call it like this:
749 BODY (BODY_DATA, JMPBUF)
751 BODY_DATA is just the BODY_DATA argument we received; we pass it
752 through to BODY as its first argument. The caller can make
753 BODY_DATA point to anything useful that BODY might need.
754 JMPBUF is the Scheme jmpbuf object corresponding to this catch,
755 which we have just created and initialized.
757 HANDLER is a pointer to a C function to deal with a throw to TAG,
758 should one occur. We call it like this:
759 HANDLER (HANDLER_DATA, THROWN_TAG, THROW_ARGS)
761 HANDLER_DATA is the HANDLER_DATA argument we recevied; it's the
762 same idea as BODY_DATA above.
763 THROWN_TAG is the tag that the user threw to; usually this is
764 TAG, but it could be something else if TAG was #t (i.e., a
765 catch-all), or the user threw to a jmpbuf.
766 THROW_ARGS is the list of arguments the user passed to the THROW
769 BODY_DATA is just a pointer we pass through to BODY. HANDLER_DATA
770 is just a pointer we pass through to HANDLER. We don't actually
771 use either of those pointers otherwise ourselves. The idea is
772 that, if our caller wants to communicate something to BODY or
773 HANDLER, it can pass a pointer to it as MUMBLE_DATA, which BODY and
774 HANDLER can then use. Think of it as a way to make BODY and
775 HANDLER closures, not just functions; MUMBLE_DATA points to the
778 Of course, it's up to the caller to make sure that any data a
779 MUMBLE_DATA needs is protected from GC. A common way to do this is
780 to make MUMBLE_DATA a pointer to data stored in an automatic
781 structure variable; since the collector must scan the stack for
782 references anyway, this assures that any references in MUMBLE_DATA
785 ** The new function scm_internal_lazy_catch is exactly like
786 scm_internal_catch, except:
788 - It does not unwind the stack (this is the major difference).
789 - If handler returns, its value is returned from the throw.
790 - BODY always receives #f as its JMPBUF argument (since there's no
791 jmpbuf associated with a lazy catch, because we don't unwind the
794 ** scm_body_thunk is a new body function you can pass to
795 scm_internal_catch if you want the body to be like Scheme's `catch'
796 --- a thunk, or a function of one argument if the tag is #f.
798 BODY_DATA is a pointer to a scm_body_thunk_data structure, which
799 contains the Scheme procedure to invoke as the body, and the tag
800 we're catching. If the tag is #f, then we pass JMPBUF (created by
801 scm_internal_catch) to the body procedure; otherwise, the body gets
804 ** scm_handle_by_proc is a new handler function you can pass to
805 scm_internal_catch if you want the handler to act like Scheme's catch
806 --- call a procedure with the tag and the throw arguments.
808 If the user does a throw to this catch, this function runs a handler
809 procedure written in Scheme. HANDLER_DATA is a pointer to an SCM
810 variable holding the Scheme procedure object to invoke. It ought to
811 be a pointer to an automatic variable (i.e., one living on the stack),
812 or the procedure object should be otherwise protected from GC.
814 ** scm_handle_by_message is a new handler function to use with
815 `scm_internal_catch' if you want Guile to print a message and die.
816 It's useful for dealing with throws to uncaught keys at the top level.
818 HANDLER_DATA, if non-zero, is assumed to be a char * pointing to a
819 message header to print; if zero, we use "guile" instead. That
820 text is followed by a colon, then the message described by ARGS.
822 ** The return type of scm_boot_guile is now void; the function does
823 not return a value, and indeed, never returns at all.
825 ** The new function scm_shell makes it easy for user applications to
826 process command-line arguments in a way that is compatible with the
827 stand-alone guile interpreter (which is in turn compatible with SCSH,
830 To use the scm_shell function, first initialize any guile modules
831 linked into your application, and then call scm_shell with the values
832 of ARGC and ARGV your `main' function received. scm_shell will adding
833 any SCSH-style meta-arguments from the top of the script file to the
834 argument vector, and then process the command-line arguments. This
835 generally means loading a script file or starting up an interactive
836 command interpreter. For details, see "Changes to the stand-alone
839 ** The new functions scm_get_meta_args and scm_count_argv help you
840 implement the SCSH-style meta-argument, `\'.
842 char **scm_get_meta_args (int ARGC, char **ARGV)
843 If the second element of ARGV is a string consisting of a single
844 backslash character (i.e. "\\" in Scheme notation), open the file
845 named by the following argument, parse arguments from it, and return
846 the spliced command line. The returned array is terminated by a
849 For details of argument parsing, see above, under "guile now accepts
850 command-line arguments compatible with SCSH..."
852 int scm_count_argv (char **ARGV)
853 Count the arguments in ARGV, assuming it is terminated by a null
856 For an example of how these functions might be used, see the source
857 code for the function scm_shell in libguile/script.c.
859 You will usually want to use scm_shell instead of calling this
862 ** The new function scm_compile_shell_switches turns an array of
863 command-line arguments into Scheme code to carry out the actions they
864 describe. Given ARGC and ARGV, it returns a Scheme expression to
865 evaluate, and calls scm_set_program_arguments to make any remaining
866 command-line arguments available to the Scheme code. For example,
867 given the following arguments:
869 -e main -s ekko a speckled gecko
871 scm_set_program_arguments will return the following expression:
873 (begin (load "ekko") (main (command-line)) (quit))
875 You will usually want to use scm_shell instead of calling this
878 ** The function scm_shell_usage prints a usage message appropriate for
879 an interpreter that uses scm_compile_shell_switches to handle its
880 command-line arguments.
882 void scm_shell_usage (int FATAL, char *MESSAGE)
883 Print a usage message to the standard error output. If MESSAGE is
884 non-zero, write it before the usage message, followed by a newline.
885 If FATAL is non-zero, exit the process, using FATAL as the
886 termination status. (If you want to be compatible with Guile,
887 always use 1 as the exit status when terminating due to command-line
890 You will usually want to use scm_shell instead of calling this
893 ** scm_eval_0str now returns SCM_UNSPECIFIED if the string contains no
894 expressions. It used to return SCM_EOL. Earth-shattering.
896 ** The macros for declaring scheme objects in C code have been
897 rearranged slightly. They are now:
899 SCM_SYMBOL (C_NAME, SCHEME_NAME)
900 Declare a static SCM variable named C_NAME, and initialize it to
901 point to the Scheme symbol whose name is SCHEME_NAME. C_NAME should
902 be a C identifier, and SCHEME_NAME should be a C string.
904 SCM_GLOBAL_SYMBOL (C_NAME, SCHEME_NAME)
905 Just like SCM_SYMBOL, but make C_NAME globally visible.
907 SCM_VCELL (C_NAME, SCHEME_NAME)
908 Create a global variable at the Scheme level named SCHEME_NAME.
909 Declare a static SCM variable named C_NAME, and initialize it to
910 point to the Scheme variable's value cell.
912 SCM_GLOBAL_VCELL (C_NAME, SCHEME_NAME)
913 Just like SCM_VCELL, but make C_NAME globally visible.
915 The `guile-snarf' script writes initialization code for these macros
916 to its standard output, given C source code as input.
918 The SCM_GLOBAL macro is gone.
920 ** The scm_read_line and scm_read_line_x functions have been replaced
921 by Scheme code based on the %read-delimited! procedure (known to C
922 code as scm_read_delimited_x). See its description above for more
925 ** The function scm_sys_open has been renamed to scm_open. It now
926 returns a port instead of an FD object.
928 * The dynamic linking support has changed. For more information, see
929 libguile/DYNAMIC-LINKING.
934 User-visible changes from Thursday, September 5, 1996 until Guile 1.0
937 * Changes to the 'guile' program:
939 ** Guile now loads some new files when it starts up. Guile first
940 searches the load path for init.scm, and loads it if found. Then, if
941 Guile is not being used to execute a script, and the user's home
942 directory contains a file named `.guile', Guile loads that.
944 ** You can now use Guile as a shell script interpreter.
946 To paraphrase the SCSH manual:
948 When Unix tries to execute an executable file whose first two
949 characters are the `#!', it treats the file not as machine code to
950 be directly executed by the native processor, but as source code
951 to be executed by some interpreter. The interpreter to use is
952 specified immediately after the #! sequence on the first line of
953 the source file. The kernel reads in the name of the interpreter,
954 and executes that instead. It passes the interpreter the source
955 filename as its first argument, with the original arguments
956 following. Consult the Unix man page for the `exec' system call
957 for more information.
959 Now you can use Guile as an interpreter, using a mechanism which is a
960 compatible subset of that provided by SCSH.
962 Guile now recognizes a '-s' command line switch, whose argument is the
963 name of a file of Scheme code to load. It also treats the two
964 characters `#!' as the start of a comment, terminated by `!#'. Thus,
965 to make a file of Scheme code directly executable by Unix, insert the
966 following two lines at the top of the file:
968 #!/usr/local/bin/guile -s
971 Guile treats the argument of the `-s' command-line switch as the name
972 of a file of Scheme code to load, and treats the sequence `#!' as the
973 start of a block comment, terminated by `!#'.
975 For example, here's a version of 'echo' written in Scheme:
977 #!/usr/local/bin/guile -s
979 (let loop ((args (cdr (program-arguments))))
983 (if (pair? (cdr args))
988 Why does `#!' start a block comment terminated by `!#', instead of the
989 end of the line? That is the notation SCSH uses, and although we
990 don't yet support the other SCSH features that motivate that choice,
991 we would like to be backward-compatible with any existing Guile
992 scripts once we do. Furthermore, if the path to Guile on your system
993 is too long for your kernel, you can start the script with this
997 exec /really/long/path/to/guile -s "$0" ${1+"$@"}
1000 Note that some very old Unix systems don't support the `#!' syntax.
1003 ** You can now run Guile without installing it.
1005 Previous versions of the interactive Guile interpreter (`guile')
1006 couldn't start up unless Guile's Scheme library had been installed;
1007 they used the value of the environment variable `SCHEME_LOAD_PATH'
1008 later on in the startup process, but not to find the startup code
1009 itself. Now Guile uses `SCHEME_LOAD_PATH' in all searches for Scheme
1012 To run Guile without installing it, build it in the normal way, and
1013 then set the environment variable `SCHEME_LOAD_PATH' to a
1014 colon-separated list of directories, including the top-level directory
1015 of the Guile sources. For example, if you unpacked Guile so that the
1016 full filename of this NEWS file is /home/jimb/guile-1.0b3/NEWS, then
1019 export SCHEME_LOAD_PATH=/home/jimb/my-scheme:/home/jimb/guile-1.0b3
1022 ** Guile's read-eval-print loop no longer prints #<unspecified>
1023 results. If the user wants to see this, she can evaluate the
1024 expression (assert-repl-print-unspecified #t), perhaps in her startup
1027 ** Guile no longer shows backtraces by default when an error occurs;
1028 however, it does display a message saying how to get one, and how to
1029 request that they be displayed by default. After an error, evaluate
1031 to see a backtrace, and
1032 (debug-enable 'backtrace)
1033 to see them by default.
1037 * Changes to Guile Scheme:
1039 ** Guile now distinguishes between #f and the empty list.
1041 This is for compatibility with the IEEE standard, the (possibly)
1042 upcoming Revised^5 Report on Scheme, and many extant Scheme
1045 Guile used to have #f and '() denote the same object, to make Scheme's
1046 type system more compatible with Emacs Lisp's. However, the change
1047 caused too much trouble for Scheme programmers, and we found another
1048 way to reconcile Emacs Lisp with Scheme that didn't require this.
1051 ** Guile's delq, delv, delete functions, and their destructive
1052 counterparts, delq!, delv!, and delete!, now remove all matching
1053 elements from the list, not just the first. This matches the behavior
1054 of the corresponding Emacs Lisp functions, and (I believe) the Maclisp
1055 functions which inspired them.
1057 I recognize that this change may break code in subtle ways, but it
1058 seems best to make the change before the FSF's first Guile release,
1062 ** The compiled-library-path function has been deleted from libguile.
1064 ** The facilities for loading Scheme source files have changed.
1066 *** The variable %load-path now tells Guile which directories to search
1067 for Scheme code. Its value is a list of strings, each of which names
1070 *** The variable %load-extensions now tells Guile which extensions to
1071 try appending to a filename when searching the load path. Its value
1072 is a list of strings. Its default value is ("" ".scm").
1074 *** (%search-load-path FILENAME) searches the directories listed in the
1075 value of the %load-path variable for a Scheme file named FILENAME,
1076 with all the extensions listed in %load-extensions. If it finds a
1077 match, then it returns its full filename. If FILENAME is absolute, it
1078 returns it unchanged. Otherwise, it returns #f.
1080 %search-load-path will not return matches that refer to directories.
1082 *** (primitive-load FILENAME :optional CASE-INSENSITIVE-P SHARP)
1083 uses %seach-load-path to find a file named FILENAME, and loads it if
1084 it finds it. If it can't read FILENAME for any reason, it throws an
1087 The arguments CASE-INSENSITIVE-P and SHARP are interpreted as by the
1090 *** load uses the same searching semantics as primitive-load.
1092 *** The functions %try-load, try-load-with-path, %load, load-with-path,
1093 basic-try-load-with-path, basic-load-with-path, try-load-module-with-
1094 path, and load-module-with-path have been deleted. The functions
1095 above should serve their purposes.
1097 *** If the value of the variable %load-hook is a procedure,
1098 `primitive-load' applies its value to the name of the file being
1099 loaded (without the load path directory name prepended). If its value
1100 is #f, it is ignored. Otherwise, an error occurs.
1102 This is mostly useful for printing load notification messages.
1105 ** The function `eval!' is no longer accessible from the scheme level.
1106 We can't allow operations which introduce glocs into the scheme level,
1107 because Guile's type system can't handle these as data. Use `eval' or
1108 `read-and-eval!' (see below) as replacement.
1110 ** The new function read-and-eval! reads an expression from PORT,
1111 evaluates it, and returns the result. This is more efficient than
1112 simply calling `read' and `eval', since it is not necessary to make a
1113 copy of the expression for the evaluator to munge.
1115 Its optional arguments CASE_INSENSITIVE_P and SHARP are interpreted as
1116 for the `read' function.
1119 ** The function `int?' has been removed; its definition was identical
1120 to that of `integer?'.
1122 ** The functions `<?', `<?', `<=?', `=?', `>?', and `>=?'. Code should
1123 use the R4RS names for these functions.
1125 ** The function object-properties no longer returns the hash handle;
1126 it simply returns the object's property list.
1128 ** Many functions have been changed to throw errors, instead of
1129 returning #f on failure. The point of providing exception handling in
1130 the language is to simplify the logic of user code, but this is less
1131 useful if Guile's primitives don't throw exceptions.
1133 ** The function `fileno' has been renamed from `%fileno'.
1135 ** The function primitive-mode->fdes returns #t or #f now, not 1 or 0.
1138 * Changes to Guile's C interface:
1140 ** The library's initialization procedure has been simplified.
1141 scm_boot_guile now has the prototype:
1143 void scm_boot_guile (int ARGC,
1145 void (*main_func) (),
1148 scm_boot_guile calls MAIN_FUNC, passing it CLOSURE, ARGC, and ARGV.
1149 MAIN_FUNC should do all the work of the program (initializing other
1150 packages, reading user input, etc.) before returning. When MAIN_FUNC
1151 returns, call exit (0); this function never returns. If you want some
1152 other exit value, MAIN_FUNC may call exit itself.
1154 scm_boot_guile arranges for program-arguments to return the strings
1155 given by ARGC and ARGV. If MAIN_FUNC modifies ARGC/ARGV, should call
1156 scm_set_program_arguments with the final list, so Scheme code will
1157 know which arguments have been processed.
1159 scm_boot_guile establishes a catch-all catch handler which prints an
1160 error message and exits the process. This means that Guile exits in a
1161 coherent way when system errors occur and the user isn't prepared to
1162 handle it. If the user doesn't like this behavior, they can establish
1163 their own universal catcher in MAIN_FUNC to shadow this one.
1165 Why must the caller do all the real work from MAIN_FUNC? The garbage
1166 collector assumes that all local variables of type SCM will be above
1167 scm_boot_guile's stack frame on the stack. If you try to manipulate
1168 SCM values after this function returns, it's the luck of the draw
1169 whether the GC will be able to find the objects you allocate. So,
1170 scm_boot_guile function exits, rather than returning, to discourage
1171 people from making that mistake.
1173 The IN, OUT, and ERR arguments were removed; there are other
1174 convenient ways to override these when desired.
1176 The RESULT argument was deleted; this function should never return.
1178 The BOOT_CMD argument was deleted; the MAIN_FUNC argument is more
1182 ** Guile's header files should no longer conflict with your system's
1185 In order to compile code which #included <libguile.h>, previous
1186 versions of Guile required you to add a directory containing all the
1187 Guile header files to your #include path. This was a problem, since
1188 Guile's header files have names which conflict with many systems'
1191 Now only <libguile.h> need appear in your #include path; you must
1192 refer to all Guile's other header files as <libguile/mumble.h>.
1193 Guile's installation procedure puts libguile.h in $(includedir), and
1194 the rest in $(includedir)/libguile.
1197 ** Two new C functions, scm_protect_object and scm_unprotect_object,
1198 have been added to the Guile library.
1200 scm_protect_object (OBJ) protects OBJ from the garbage collector.
1201 OBJ will not be freed, even if all other references are dropped,
1202 until someone does scm_unprotect_object (OBJ). Both functions
1205 Note that calls to scm_protect_object do not nest. You can call
1206 scm_protect_object any number of times on a given object, and the
1207 next call to scm_unprotect_object will unprotect it completely.
1209 Basically, scm_protect_object and scm_unprotect_object just
1210 maintain a list of references to things. Since the GC knows about
1211 this list, all objects it mentions stay alive. scm_protect_object
1212 adds its argument to the list; scm_unprotect_object remove its
1213 argument from the list.
1216 ** scm_eval_0str now returns the value of the last expression
1219 ** The new function scm_read_0str reads an s-expression from a
1220 null-terminated string, and returns it.
1222 ** The new function `scm_stdio_to_port' converts a STDIO file pointer
1223 to a Scheme port object.
1225 ** The new function `scm_set_program_arguments' allows C code to set
1226 the value teruturned by the Scheme `program-arguments' function.
1231 * Guile no longer includes sophisticated Tcl/Tk support.
1233 The old Tcl/Tk support was unsatisfying to us, because it required the
1234 user to link against the Tcl library, as well as Tk and Guile. The
1235 interface was also un-lispy, in that it preserved Tcl/Tk's practice of
1236 referring to widgets by names, rather than exporting widgets to Scheme
1237 code as a special datatype.
1239 In the Usenix Tk Developer's Workshop held in July 1996, the Tcl/Tk
1240 maintainers described some very interesting changes in progress to the
1241 Tcl/Tk internals, which would facilitate clean interfaces between lone
1242 Tk and other interpreters --- even for garbage-collected languages
1243 like Scheme. They expected the new Tk to be publicly available in the
1246 Since it seems that Guile might soon have a new, cleaner interface to
1247 lone Tk, and that the old Guile/Tk glue code would probably need to be
1248 completely rewritten, we (Jim Blandy and Richard Stallman) have
1249 decided not to support the old code. We'll spend the time instead on
1250 a good interface to the newer Tk, as soon as it is available.
1252 Until then, gtcltk-lib provides trivial, low-maintenance functionality.
1255 Copyright information:
1257 Copyright (C) 1996,1997 Free Software Foundation, Inc.
1259 Permission is granted to anyone to make or distribute verbatim copies
1260 of this document as received, in any medium, provided that the
1261 copyright notice and this permission notice are preserved,
1262 thus giving the recipient permission to redistribute in turn.
1264 Permission is granted to distribute modified versions
1265 of this document, or of portions of it,
1266 under the above conditions, provided also that they
1267 carry prominent notices stating who last changed them.
1272 paragraph-separate: "[
\f]*$"