-Guile NEWS --- history of user-visible changes. 2 Aug 1996 -*- text -*-
-Copyright (C) 1996 Free Software Foundation, Inc.
+Guile NEWS --- history of user-visible changes. -*- text -*-
+Copyright (C) 1996, 1997 Free Software Foundation, Inc.
See the end for copying conditions.
Please send Guile bug reports to bug-guile@prep.ai.mit.edu.
\f
-Guile 1.0b3
+Changes since Guile 1.2:
-Changes since Thursday, September 5:
+* Changes to the distribution
+* Changes to the stand-alone interpreter
-* Guile now distinguishes between #f and the empty list.
+* Changes to the procedure for linking libguile with your programs
-This is for compatibility with the IEEE standard, the (possibly)
-upcoming Revised^5 Report on Scheme, and many extant Scheme
-implementations.
+* Changes to Scheme functions and syntax
-Guile used to have #f and '() denote the same object, to make Scheme's
-type system more compatible with Emacs Lisp's. However, the change
-caused too much trouble for Scheme programmers, and we found another
-way to reconcile Emacs Lisp with Scheme that didn't require this.
+** There is now some basic support for fluids. Please read
+"libguile/fluid.h" to find out more. It is accessible from Scheme with
+the following builtin procedures:
+
+ (make-fluid)
+
+ Create a new fluid object.
+
+ (fluid-ref FLUID)
+ (fluid-set! FLUID VAL)
+
+ Access/modify the fluid FLUID. Modifications are only visible
+ within the current dynamic root (that includes threads).
+
+There is no `fluid-let' yet.
+
+* Changes to system call interfaces:
+
+** close-port, close-input-port and close-output-port now return a
+boolean instead of an `unspecified' object. #t means that the port
+was successfully closed, while #f means it was already closed. It is
+also now possible for these procedures to raise an exception if an
+error occurs (some errors from write can be delayed until close.)
+
+** The following new procedures have been added (most use scsh
+interfaces):
+
+** close PORT/FD
+Similar to close-port, but also works on file descriptors. A side
+effect of closing a file descriptor is that any ports using that file
+descriptor are moved to a different file descriptor and have
+their revealed counts set to zero.
+
+The next five procedures perform a dup2 system call, if NEWFD (an
+integer) is supplied, otherwise a dup. The file descriptor to be
+duplicated can be supplied as an integer or wrapped in a port. The
+type of value returned varies depending on which procedure is used.
+
+All procedures also have the side effect when performing dup2 that any
+ports using NEWFD are moved to a different file descriptor and have
+their revealed counts set to zero.
+
+** dup->fdes PORT/FD [NEWFD]
+Returns an integer file descriptor.
+
+** dup->inport PORT/FD [NEWFD]
+Returns a new input port using the new file descriptor.
+
+** dup->outport PORT/FD [NEWFD]
+Returns a new output port using the new file descriptor.
+
+** dup PORT/FD [NEWFD]
+Returns a new port if PORT/FD is a port, with the same mode as the
+supplied port, otherwise returns an integer file descriptor.
+
+** dup->port PORT/FD MODE [NEWFD]
+Returns a new port using the new file descriptor. MODE supplies a
+mode string for the port (as for `open-file').
+
+** primitive-dup PORT/FD
+Performs a dup system call on the file descriptor FD, or the file
+descriptor underlying PORT and returns a new integer file descriptor.
+
+** primitive-dup2 PORT/FD NEWFD
+
+Performs a dup2 system call on the file descriptor FD, or the file
+descriptor underlying PORT, using NEWFD (an integer) as the target
+file descriptor. Any ports using NEWFD are moved to a different file
+descriptor and have their revealed counts set to zero. The value
+returned is NEWFD.
+
+** port->fdes PORT
+Returns the integer file descriptor underlying PORT. As a
+side effect the revealed count of PORT is incremented.
+
+** fdes->inport FDES
+Returns an existing input port which has FDES as its underlying file
+descriptor, if one exists, and increments its revealed count.
+Otherwise, returns a new input port with a revealed count of 1.
+
+** fdes->outport FDES
+Returns an existing output port which has FDES as its underlying file
+descriptor, if one exists, and increments its revealed count.
+Otherwise, returns a new output port with a revealed count of 1.
+
+** setenv [NAME] [VALUE]
+If VALUE is `#f', removes NAME from the environment. Otherwise
+adds the string NAME=VALUE to the environment, replacing any previous
+value for NAME.
+
+** primitive-exit [STATUS]
+Terminates the current process without unwinding the Scheme stack.
+This would usually be used after a fork.
+
+* Changes to the gh_ interface
+
+* Changes to the scm_ interface
+
+\f
+Changes in Guile 1.2 (released Tuesday, June 24 1997):
+
+* Changes to the distribution
+
+** Nightly snapshots are now available from ftp.red-bean.com.
+The old server, ftp.cyclic.com, has been relinquished to its rightful
+owner.
+
+Nightly snapshots of the Guile development sources are now available via
+anonymous FTP from ftp.red-bean.com, as /pub/guile/guile-snap.tar.gz.
+
+Via the web, that's: ftp://ftp.red-bean.com/pub/guile/guile-snap.tar.gz
+For getit, that's: ftp.red-bean.com:/pub/guile/guile-snap.tar.gz
+
+** To run Guile without installing it, the procedure has changed a bit.
+
+If you used a separate build directory to compile Guile, you'll need
+to include the build directory in SCHEME_LOAD_PATH, as well as the
+source directory. See the `INSTALL' file for examples.
+
+* Changes to the procedure for linking libguile with your programs
+
+** The standard Guile load path for Scheme code now includes
+$(datadir)/guile (usually /usr/local/share/guile). This means that
+you can install your own Scheme files there, and Guile will find them.
+(Previous versions of Guile only checked a directory whose name
+contained the Guile version number, so you had to re-install or move
+your Scheme sources each time you installed a fresh version of Guile.)
+
+The load path also includes $(datadir)/guile/site; we recommend
+putting individual Scheme files there. If you want to install a
+package with multiple source files, create a directory for them under
+$(datadir)/guile.
+
+** Guile 1.2 will now use the Rx regular expression library, if it is
+installed on your system. When you are linking libguile into your own
+programs, this means you will have to link against -lguile, -lqt (if
+you configured Guile with thread support), and -lrx.
+
+If you are using autoconf to generate configuration scripts for your
+application, the following lines should suffice to add the appropriate
+libraries to your link command:
+
+### Find Rx, quickthreads and libguile.
+AC_CHECK_LIB(rx, main)
+AC_CHECK_LIB(qt, main)
+AC_CHECK_LIB(guile, scm_shell)
+
+The Guile 1.2 distribution does not contain sources for the Rx
+library, as Guile 1.0 did. If you want to use Rx, you'll need to
+retrieve it from a GNU FTP site and install it separately.
+
+* Changes to Scheme functions and syntax
+
+** The dynamic linking features of Guile are now enabled by default.
+You can disable them by giving the `--disable-dynamic-linking' option
+to configure.
+
+ (dynamic-link FILENAME)
+
+ Find the object file denoted by FILENAME (a string) and link it
+ into the running Guile application. When everything works out,
+ return a Scheme object suitable for representing the linked object
+ file. Otherwise an error is thrown. How object files are
+ searched is system dependent.
+
+ (dynamic-object? VAL)
+
+ Determine whether VAL represents a dynamically linked object file.
+
+ (dynamic-unlink DYNOBJ)
+
+ Unlink the indicated object file from the application. DYNOBJ
+ should be one of the values returned by `dynamic-link'.
+
+ (dynamic-func FUNCTION DYNOBJ)
+
+ Search the C function indicated by FUNCTION (a string or symbol)
+ in DYNOBJ and return some Scheme object that can later be used
+ with `dynamic-call' to actually call this function. Right now,
+ these Scheme objects are formed by casting the address of the
+ function to `long' and converting this number to its Scheme
+ representation.
+
+ (dynamic-call FUNCTION DYNOBJ)
+
+ Call the C function indicated by FUNCTION and DYNOBJ. The
+ function is passed no arguments and its return value is ignored.
+ When FUNCTION is something returned by `dynamic-func', call that
+ function and ignore DYNOBJ. When FUNCTION is a string (or symbol,
+ etc.), look it up in DYNOBJ; this is equivalent to
+
+ (dynamic-call (dynamic-func FUNCTION DYNOBJ) #f)
+
+ Interrupts are deferred while the C function is executing (with
+ SCM_DEFER_INTS/SCM_ALLOW_INTS).
+
+ (dynamic-args-call FUNCTION DYNOBJ ARGS)
+
+ Call the C function indicated by FUNCTION and DYNOBJ, but pass it
+ some arguments and return its return value. The C function is
+ expected to take two arguments and return an `int', just like
+ `main':
+
+ int c_func (int argc, char **argv);
+
+ ARGS must be a list of strings and is converted into an array of
+ `char *'. The array is passed in ARGV and its size in ARGC. The
+ return value is converted to a Scheme number and returned from the
+ call to `dynamic-args-call'.
+
+When dynamic linking is disabled or not supported on your system,
+the above functions throw errors, but they are still available.
+
+Here is a small example that works on GNU/Linux:
+
+ (define libc-obj (dynamic-link "libc.so"))
+ (dynamic-args-call 'rand libc-obj '())
+
+See the file `libguile/DYNAMIC-LINKING' for additional comments.
+
+** The #/ syntax for module names is depreciated, and will be removed
+in a future version of Guile. Instead of
+
+ #/foo/bar/baz
+
+instead write
+
+ (foo bar baz)
+
+The latter syntax is more consistent with existing Lisp practice.
+
+** Guile now does fancier printing of structures. Structures are the
+underlying implementation for records, which in turn are used to
+implement modules, so all of these object now print differently and in
+a more informative way.
+
+The Scheme printer will examine the builtin variable *struct-printer*
+whenever it needs to print a structure object. When this variable is
+not `#f' it is deemed to be a procedure and will be applied to the
+structure object and the output port. When *struct-printer* is `#f'
+or the procedure return `#f' the structure object will be printed in
+the boring #<struct 80458270> form.
+
+This hook is used by some routines in ice-9/boot-9.scm to implement
+type specific printing routines. Please read the comments there about
+"printing structs".
+
+One of the more specific uses of structs are records. The printing
+procedure that could be passed to MAKE-RECORD-TYPE is now actually
+called. It should behave like a *struct-printer* procedure (described
+above).
+
+** Guile now supports a new R4RS-compliant syntax for keywords. A
+token of the form #:NAME, where NAME has the same syntax as a Scheme
+symbol, is the external representation of the keyword named NAME.
+Keyword objects print using this syntax as well, so values containing
+keyword objects can be read back into Guile. When used in an
+expression, keywords are self-quoting objects.
+
+Guile suports this read syntax, and uses this print syntax, regardless
+of the current setting of the `keyword' read option. The `keyword'
+read option only controls whether Guile recognizes the `:NAME' syntax,
+which is incompatible with R4RS. (R4RS says such token represent
+symbols.)
+
+** Guile has regular expression support again. Guile 1.0 included
+functions for matching regular expressions, based on the Rx library.
+In Guile 1.1, the Guile/Rx interface was removed to simplify the
+distribution, and thus Guile had no regular expression support. Guile
+1.2 again supports the most commonly used functions, and supports all
+of SCSH's regular expression functions.
+
+If your system does not include a POSIX regular expression library,
+and you have not linked Guile with a third-party regexp library such as
+Rx, these functions will not be available. You can tell whether your
+Guile installation includes regular expression support by checking
+whether the `*features*' list includes the `regex' symbol.
+
+*** regexp functions
+
+By default, Guile supports POSIX extended regular expressions. That
+means that the characters `(', `)', `+' and `?' are special, and must
+be escaped if you wish to match the literal characters.
+
+This regular expression interface was modeled after that implemented
+by SCSH, the Scheme Shell. It is intended to be upwardly compatible
+with SCSH regular expressions.
+
+**** Function: string-match PATTERN STR [START]
+ Compile the string PATTERN into a regular expression and compare
+ it with STR. The optional numeric argument START specifies the
+ position of STR at which to begin matching.
+
+ `string-match' returns a "match structure" which describes what,
+ if anything, was matched by the regular expression. *Note Match
+ Structures::. If STR does not match PATTERN at all,
+ `string-match' returns `#f'.
+
+ Each time `string-match' is called, it must compile its PATTERN
+argument into a regular expression structure. This operation is
+expensive, which makes `string-match' inefficient if the same regular
+expression is used several times (for example, in a loop). For better
+performance, you can compile a regular expression in advance and then
+match strings against the compiled regexp.
+
+**** Function: make-regexp STR [FLAGS]
+ Compile the regular expression described by STR, and return the
+ compiled regexp structure. If STR does not describe a legal
+ regular expression, `make-regexp' throws a
+ `regular-expression-syntax' error.
+
+ FLAGS may be the bitwise-or of one or more of the following:
+
+**** Constant: regexp/extended
+ Use POSIX Extended Regular Expression syntax when interpreting
+ STR. If not set, POSIX Basic Regular Expression syntax is used.
+ If the FLAGS argument is omitted, we assume regexp/extended.
+
+**** Constant: regexp/icase
+ Do not differentiate case. Subsequent searches using the
+ returned regular expression will be case insensitive.
+
+**** Constant: regexp/newline
+ Match-any-character operators don't match a newline.
+
+ A non-matching list ([^...]) not containing a newline matches a
+ newline.
+
+ Match-beginning-of-line operator (^) matches the empty string
+ immediately after a newline, regardless of whether the FLAGS
+ passed to regexp-exec contain regexp/notbol.
+
+ Match-end-of-line operator ($) matches the empty string
+ immediately before a newline, regardless of whether the FLAGS
+ passed to regexp-exec contain regexp/noteol.
+
+**** Function: regexp-exec REGEXP STR [START [FLAGS]]
+ Match the compiled regular expression REGEXP against `str'. If
+ the optional integer START argument is provided, begin matching
+ from that position in the string. Return a match structure
+ describing the results of the match, or `#f' if no match could be
+ found.
+
+ FLAGS may be the bitwise-or of one or more of the following:
+
+**** Constant: regexp/notbol
+ The match-beginning-of-line operator always fails to match (but
+ see the compilation flag regexp/newline above) This flag may be
+ used when different portions of a string are passed to
+ regexp-exec and the beginning of the string should not be
+ interpreted as the beginning of the line.
+
+**** Constant: regexp/noteol
+ The match-end-of-line operator always fails to match (but see the
+ compilation flag regexp/newline above)
+
+**** Function: regexp? OBJ
+ Return `#t' if OBJ is a compiled regular expression, or `#f'
+ otherwise.
+
+ Regular expressions are commonly used to find patterns in one string
+and replace them with the contents of another string.
+
+**** Function: regexp-substitute PORT MATCH [ITEM...]
+ Write to the output port PORT selected contents of the match
+ structure MATCH. Each ITEM specifies what should be written, and
+ may be one of the following arguments:
+
+ * A string. String arguments are written out verbatim.
+
+ * An integer. The submatch with that number is written.
+
+ * The symbol `pre'. The portion of the matched string preceding
+ the regexp match is written.
+
+ * The symbol `post'. The portion of the matched string
+ following the regexp match is written.
+
+ PORT may be `#f', in which case nothing is written; instead,
+ `regexp-substitute' constructs a string from the specified ITEMs
+ and returns that.
+
+**** Function: regexp-substitute/global PORT REGEXP TARGET [ITEM...]
+ Similar to `regexp-substitute', but can be used to perform global
+ substitutions on STR. Instead of taking a match structure as an
+ argument, `regexp-substitute/global' takes two string arguments: a
+ REGEXP string describing a regular expression, and a TARGET string
+ which should be matched against this regular expression.
+
+ Each ITEM behaves as in REGEXP-SUBSTITUTE, with the following
+ exceptions:
+
+ * A function may be supplied. When this function is called, it
+ will be passed one argument: a match structure for a given
+ regular expression match. It should return a string to be
+ written out to PORT.
+
+ * The `post' symbol causes `regexp-substitute/global' to recurse
+ on the unmatched portion of STR. This *must* be supplied in
+ order to perform global search-and-replace on STR; if it is
+ not present among the ITEMs, then `regexp-substitute/global'
+ will return after processing a single match.
+
+*** Match Structures
+
+ A "match structure" is the object returned by `string-match' and
+`regexp-exec'. It describes which portion of a string, if any, matched
+the given regular expression. Match structures include: a reference to
+the string that was checked for matches; the starting and ending
+positions of the regexp match; and, if the regexp included any
+parenthesized subexpressions, the starting and ending positions of each
+submatch.
+
+ In each of the regexp match functions described below, the `match'
+argument must be a match structure returned by a previous call to
+`string-match' or `regexp-exec'. Most of these functions return some
+information about the original target string that was matched against a
+regular expression; we will call that string TARGET for easy reference.
+
+**** Function: regexp-match? OBJ
+ Return `#t' if OBJ is a match structure returned by a previous
+ call to `regexp-exec', or `#f' otherwise.
+
+**** Function: match:substring MATCH [N]
+ Return the portion of TARGET matched by subexpression number N.
+ Submatch 0 (the default) represents the entire regexp match. If
+ the regular expression as a whole matched, but the subexpression
+ number N did not match, return `#f'.
+
+**** Function: match:start MATCH [N]
+ Return the starting position of submatch number N.
+
+**** Function: match:end MATCH [N]
+ Return the ending position of submatch number N.
+
+**** Function: match:prefix MATCH
+ Return the unmatched portion of TARGET preceding the regexp match.
+
+**** Function: match:suffix MATCH
+ Return the unmatched portion of TARGET following the regexp match.
+
+**** Function: match:count MATCH
+ Return the number of parenthesized subexpressions from MATCH.
+ Note that the entire regular expression match itself counts as a
+ subexpression, and failed submatches are included in the count.
+
+**** Function: match:string MATCH
+ Return the original TARGET string.
+
+*** Backslash Escapes
+
+ Sometimes you will want a regexp to match characters like `*' or `$'
+exactly. For example, to check whether a particular string represents
+a menu entry from an Info node, it would be useful to match it against
+a regexp like `^* [^:]*::'. However, this won't work; because the
+asterisk is a metacharacter, it won't match the `*' at the beginning of
+the string. In this case, we want to make the first asterisk un-magic.
+
+ You can do this by preceding the metacharacter with a backslash
+character `\'. (This is also called "quoting" the metacharacter, and
+is known as a "backslash escape".) When Guile sees a backslash in a
+regular expression, it considers the following glyph to be an ordinary
+character, no matter what special meaning it would ordinarily have.
+Therefore, we can make the above example work by changing the regexp to
+`^\* [^:]*::'. The `\*' sequence tells the regular expression engine
+to match only a single asterisk in the target string.
+
+ Since the backslash is itself a metacharacter, you may force a
+regexp to match a backslash in the target string by preceding the
+backslash with itself. For example, to find variable references in a
+TeX program, you might want to find occurrences of the string `\let\'
+followed by any number of alphabetic characters. The regular expression
+`\\let\\[A-Za-z]*' would do this: the double backslashes in the regexp
+each match a single backslash in the target string.
+
+**** Function: regexp-quote STR
+ Quote each special character found in STR with a backslash, and
+ return the resulting string.
+
+ *Very important:* Using backslash escapes in Guile source code (as
+in Emacs Lisp or C) can be tricky, because the backslash character has
+special meaning for the Guile reader. For example, if Guile encounters
+the character sequence `\n' in the middle of a string while processing
+Scheme code, it replaces those characters with a newline character.
+Similarly, the character sequence `\t' is replaced by a horizontal tab.
+Several of these "escape sequences" are processed by the Guile reader
+before your code is executed. Unrecognized escape sequences are
+ignored: if the characters `\*' appear in a string, they will be
+translated to the single character `*'.
+
+ This translation is obviously undesirable for regular expressions,
+since we want to be able to include backslashes in a string in order to
+escape regexp metacharacters. Therefore, to make sure that a backslash
+is preserved in a string in your Guile program, you must use *two*
+consecutive backslashes:
+
+ (define Info-menu-entry-pattern (make-regexp "^\\* [^:]*"))
+
+ The string in this example is preprocessed by the Guile reader before
+any code is executed. The resulting argument to `make-regexp' is the
+string `^\* [^:]*', which is what we really want.
+
+ This also means that in order to write a regular expression that
+matches a single backslash character, the regular expression string in
+the source code must include *four* backslashes. Each consecutive pair
+of backslashes gets translated by the Guile reader to a single
+backslash, and the resulting double-backslash is interpreted by the
+regexp engine as matching a single backslash character. Hence:
+
+ (define tex-variable-pattern (make-regexp "\\\\let\\\\=[A-Za-z]*"))
+
+ The reason for the unwieldiness of this syntax is historical. Both
+regular expression pattern matchers and Unix string processing systems
+have traditionally used backslashes with the special meanings described
+above. The POSIX regular expression specification and ANSI C standard
+both require these semantics. Attempting to abandon either convention
+would cause other kinds of compatibility problems, possibly more severe
+ones. Therefore, without extending the Scheme reader to support
+strings with different quoting conventions (an ungainly and confusing
+extension when implemented in other languages), we must adhere to this
+cumbersome escape syntax.
+
+* Changes to the gh_ interface
+
+* Changes to the scm_ interface
+
+* Changes to system call interfaces:
+
+** The value returned by `raise' is now unspecified. It throws an exception
+if an error occurs.
+
+*** A new procedure `sigaction' can be used to install signal handlers
+
+(sigaction signum [action] [flags])
+
+signum is the signal number, which can be specified using the value
+of SIGINT etc.
+
+If action is omitted, sigaction returns a pair: the CAR is the current
+signal hander, which will be either an integer with the value SIG_DFL
+(default action) or SIG_IGN (ignore), or the Scheme procedure which
+handles the signal, or #f if a non-Scheme procedure handles the
+signal. The CDR contains the current sigaction flags for the handler.
+
+If action is provided, it is installed as the new handler for signum.
+action can be a Scheme procedure taking one argument, or the value of
+SIG_DFL (default action) or SIG_IGN (ignore), or #f to restore
+whatever signal handler was installed before sigaction was first used.
+Flags can optionally be specified for the new handler (SA_RESTART is
+always used if the system provides it, so need not be specified.) The
+return value is a pair with information about the old handler as
+described above.
+
+This interface does not provide access to the "signal blocking"
+facility. Maybe this is not needed, since the thread support may
+provide solutions to the problem of consistent access to data
+structures.
+
+*** A new procedure `flush-all-ports' is equivalent to running
+`force-output' on every port open for output.
+
+** Guile now provides information on how it was built, via the new
+global variable, %guile-build-info. This variable records the values
+of the standard GNU makefile directory variables as an assocation
+list, mapping variable names (symbols) onto directory paths (strings).
+For example, to find out where the Guile link libraries were
+installed, you can say:
+
+guile -c "(display (assq-ref %guile-build-info 'libdir)) (newline)"
+
+
+* Changes to the scm_ interface
+
+** The new function scm_handle_by_message_noexit is just like the
+existing scm_handle_by_message function, except that it doesn't call
+exit to terminate the process. Instead, it prints a message and just
+returns #f. This might be a more appropriate catch-all handler for
+new dynamic roots and threads.
+
+\f
+Changes in Guile 1.1 (released Friday, May 16 1997):
+
+* Changes to the distribution.
+
+The Guile 1.0 distribution has been split up into several smaller
+pieces:
+guile-core --- the Guile interpreter itself.
+guile-tcltk --- the interface between the Guile interpreter and
+ Tcl/Tk; Tcl is an interpreter for a stringy language, and Tk
+ is a toolkit for building graphical user interfaces.
+guile-rgx-ctax --- the interface between Guile and the Rx regular
+ expression matcher, and the translator for the Ctax
+ programming language. These are packaged together because the
+ Ctax translator uses Rx to parse Ctax source code.
+
+This NEWS file describes the changes made to guile-core since the 1.0
+release.
+
+We no longer distribute the documentation, since it was either out of
+date, or incomplete. As soon as we have current documentation, we
+will distribute it.
+
+
+
+* Changes to the stand-alone interpreter
+
+** guile now accepts command-line arguments compatible with SCSH, Olin
+Shivers' Scheme Shell.
+
+In general, arguments are evaluated from left to right, but there are
+exceptions. The following switches stop argument processing, and
+stash all remaining command-line arguments as the value returned by
+the (command-line) function.
+ -s SCRIPT load Scheme source code from FILE, and exit
+ -c EXPR evalute Scheme expression EXPR, and exit
+ -- stop scanning arguments; run interactively
+
+The switches below are processed as they are encountered.
+ -l FILE load Scheme source code from FILE
+ -e FUNCTION after reading script, apply FUNCTION to
+ command line arguments
+ -ds do -s script at this point
+ --emacs enable Emacs protocol (experimental)
+ -h, --help display this help and exit
+ -v, --version display version information and exit
+ \ read arguments from following script lines
+
+So, for example, here is a Guile script named `ekko' (thanks, Olin)
+which re-implements the traditional "echo" command:
+
+#!/usr/local/bin/guile -s
+!#
+(define (main args)
+ (map (lambda (arg) (display arg) (display " "))
+ (cdr args))
+ (newline))
+
+(main (command-line))
+
+Suppose we invoke this script as follows:
+
+ ekko a speckled gecko
+
+Through the magic of Unix script processing (triggered by the `#!'
+token at the top of the file), /usr/local/bin/guile receives the
+following list of command-line arguments:
+
+ ("-s" "./ekko" "a" "speckled" "gecko")
+
+Unix inserts the name of the script after the argument specified on
+the first line of the file (in this case, "-s"), and then follows that
+with the arguments given to the script. Guile loads the script, which
+defines the `main' function, and then applies it to the list of
+remaining command-line arguments, ("a" "speckled" "gecko").
+
+In Unix, the first line of a script file must take the following form:
+
+#!INTERPRETER ARGUMENT
+
+where INTERPRETER is the absolute filename of the interpreter
+executable, and ARGUMENT is a single command-line argument to pass to
+the interpreter.
+
+You may only pass one argument to the interpreter, and its length is
+limited. These restrictions can be annoying to work around, so Guile
+provides a general mechanism (borrowed from, and compatible with,
+SCSH) for circumventing them.
+
+If the ARGUMENT in a Guile script is a single backslash character,
+`\', Guile will open the script file, parse arguments from its second
+and subsequent lines, and replace the `\' with them. So, for example,
+here is another implementation of the `ekko' script:
+
+#!/usr/local/bin/guile \
+-e main -s
+!#
+(define (main args)
+ (for-each (lambda (arg) (display arg) (display " "))
+ (cdr args))
+ (newline))
+
+If the user invokes this script as follows:
+
+ ekko a speckled gecko
+
+Unix expands this into
+
+ /usr/local/bin/guile \ ekko a speckled gecko
+
+When Guile sees the `\' argument, it replaces it with the arguments
+read from the second line of the script, producing:
+
+ /usr/local/bin/guile -e main -s ekko a speckled gecko
+
+This tells Guile to load the `ekko' script, and apply the function
+`main' to the argument list ("a" "speckled" "gecko").
+
+Here is how Guile parses the command-line arguments:
+- Each space character terminates an argument. This means that two
+ spaces in a row introduce an empty-string argument.
+- The tab character is not permitted (unless you quote it with the
+ backslash character, as described below), to avoid confusion.
+- The newline character terminates the sequence of arguments, and will
+ also terminate a final non-empty argument. (However, a newline
+ following a space will not introduce a final empty-string argument;
+ it only terminates the argument list.)
+- The backslash character is the escape character. It escapes
+ backslash, space, tab, and newline. The ANSI C escape sequences
+ like \n and \t are also supported. These produce argument
+ constituents; the two-character combination \n doesn't act like a
+ terminating newline. The escape sequence \NNN for exactly three
+ octal digits reads as the character whose ASCII code is NNN. As
+ above, characters produced this way are argument constituents.
+ Backslash followed by other characters is not allowed.
+
+* Changes to the procedure for linking libguile with your programs
+
+** Guile now builds and installs a shared guile library, if your
+system support shared libraries. (It still builds a static library on
+all systems.) Guile automatically detects whether your system
+supports shared libraries. To prevent Guile from buildisg shared
+libraries, pass the `--disable-shared' flag to the configure script.
+
+Guile takes longer to compile when it builds shared libraries, because
+it must compile every file twice --- once to produce position-
+independent object code, and once to produce normal object code.
+
+** The libthreads library has been merged into libguile.
+
+To link a program against Guile, you now need only link against
+-lguile and -lqt; -lthreads is no longer needed. If you are using
+autoconf to generate configuration scripts for your application, the
+following lines should suffice to add the appropriate libraries to
+your link command:
+
+### Find quickthreads and libguile.
+AC_CHECK_LIB(qt, main)
+AC_CHECK_LIB(guile, scm_shell)
+
+* Changes to Scheme functions
+
+** Guile Scheme's special syntax for keyword objects is now optional,
+and disabled by default.
+
+The syntax variation from R4RS made it difficult to port some
+interesting packages to Guile. The routines which accepted keyword
+arguments (mostly in the module system) have been modified to also
+accept symbols whose names begin with `:'.
+
+To change the keyword syntax, you must first import the (ice-9 debug)
+module:
+ (use-modules (ice-9 debug))
+
+Then you can enable the keyword syntax as follows:
+ (read-set! keywords 'prefix)
+
+To disable keyword syntax, do this:
+ (read-set! keywords #f)
+
+** Many more primitive functions accept shared substrings as
+arguments. In the past, these functions required normal, mutable
+strings as arguments, although they never made use of this
+restriction.
+
+** The uniform array functions now operate on byte vectors. These
+functions are `array-fill!', `serial-array-copy!', `array-copy!',
+`serial-array-map', `array-map', `array-for-each', and
+`array-index-map!'.
+
+** The new functions `trace' and `untrace' implement simple debugging
+support for Scheme functions.
+
+The `trace' function accepts any number of procedures as arguments,
+and tells the Guile interpreter to display each procedure's name and
+arguments each time the procedure is invoked. When invoked with no
+arguments, `trace' returns the list of procedures currently being
+traced.
+
+The `untrace' function accepts any number of procedures as arguments,
+and tells the Guile interpreter not to trace them any more. When
+invoked with no arguments, `untrace' untraces all curretly traced
+procedures.
+
+The tracing in Guile has an advantage over most other systems: we
+don't create new procedure objects, but mark the procedure objects
+themselves. This means that anonymous and internal procedures can be
+traced.
+
+** The function `assert-repl-prompt' has been renamed to
+`set-repl-prompt!'. It takes one argument, PROMPT.
+- If PROMPT is #f, the Guile read-eval-print loop will not prompt.
+- If PROMPT is a string, we use it as a prompt.
+- If PROMPT is a procedure accepting no arguments, we call it, and
+ display the result as a prompt.
+- Otherwise, we display "> ".
+
+** The new function `eval-string' reads Scheme expressions from a
+string and evaluates them, returning the value of the last expression
+in the string. If the string contains no expressions, it returns an
+unspecified value.
+
+** The new function `thunk?' returns true iff its argument is a
+procedure of zero arguments.
+
+** `defined?' is now a builtin function, instead of syntax. This
+means that its argument should be quoted. It returns #t iff its
+argument is bound in the current module.
+** The new syntax `use-modules' allows you to add new modules to your
+environment without re-typing a complete `define-module' form. It
+accepts any number of module names as arguments, and imports their
+public bindings into the current module.
-* You can now use Guile as a shell script interpreter.
+** The new function (module-defined? NAME MODULE) returns true iff
+NAME, a symbol, is defined in MODULE, a module object.
+
+** The new function `builtin-bindings' creates and returns a hash
+table containing copies of all the root module's bindings.
+
+** The new function `builtin-weak-bindings' does the same as
+`builtin-bindings', but creates a doubly-weak hash table.
+
+** The `equal?' function now considers variable objects to be
+equivalent if they have the same name and the same value.
+
+** The new function `command-line' returns the command-line arguments
+given to Guile, as a list of strings.
+
+When using guile as a script interpreter, `command-line' returns the
+script's arguments; those processed by the interpreter (like `-s' or
+`-c') are omitted. (In other words, you get the normal, expected
+behavior.) Any application that uses scm_shell to process its
+command-line arguments gets this behavior as well.
+
+** The new function `load-user-init' looks for a file called `.guile'
+in the user's home directory, and loads it if it exists. This is
+mostly for use by the code generated by scm_compile_shell_switches,
+but we thought it might also be useful in other circumstances.
+
+** The new function `log10' returns the base-10 logarithm of its
+argument.
+
+** Changes to I/O functions
+
+*** The functions `read', `primitive-load', `read-and-eval!', and
+`primitive-load-path' no longer take optional arguments controlling
+case insensitivity and a `#' parser.
+
+Case sensitivity is now controlled by a read option called
+`case-insensitive'. The user can add new `#' syntaxes with the
+`read-hash-extend' function (see below).
+
+*** The new function `read-hash-extend' allows the user to change the
+syntax of Guile Scheme in a somewhat controlled way.
+
+(read-hash-extend CHAR PROC)
+ When parsing S-expressions, if we read a `#' character followed by
+ the character CHAR, use PROC to parse an object from the stream.
+ If PROC is #f, remove any parsing procedure registered for CHAR.
+
+ The reader applies PROC to two arguments: CHAR and an input port.
+
+*** The new functions read-delimited and read-delimited! provide a
+general mechanism for doing delimited input on streams.
+
+(read-delimited DELIMS [PORT HANDLE-DELIM])
+ Read until we encounter one of the characters in DELIMS (a string),
+ or end-of-file. PORT is the input port to read from; it defaults to
+ the current input port. The HANDLE-DELIM parameter determines how
+ the terminating character is handled; it should be one of the
+ following symbols:
+
+ 'trim omit delimiter from result
+ 'peek leave delimiter character in input stream
+ 'concat append delimiter character to returned value
+ 'split return a pair: (RESULT . TERMINATOR)
+
+ HANDLE-DELIM defaults to 'peek.
+
+(read-delimited! DELIMS BUF [PORT HANDLE-DELIM START END])
+ A side-effecting variant of `read-delimited'.
+
+ The data is written into the string BUF at the indices in the
+ half-open interval [START, END); the default interval is the whole
+ string: START = 0 and END = (string-length BUF). The values of
+ START and END must specify a well-defined interval in BUF, i.e.
+ 0 <= START <= END <= (string-length BUF).
+
+ It returns NBYTES, the number of bytes read. If the buffer filled
+ up without a delimiter character being found, it returns #f. If the
+ port is at EOF when the read starts, it returns the EOF object.
+
+ If an integer is returned (i.e., the read is successfully terminated
+ by reading a delimiter character), then the HANDLE-DELIM parameter
+ determines how to handle the terminating character. It is described
+ above, and defaults to 'peek.
+
+(The descriptions of these functions were borrowed from the SCSH
+manual, by Olin Shivers and Brian Carlstrom.)
+
+*** The `%read-delimited!' function is the primitive used to implement
+`read-delimited' and `read-delimited!'.
+
+(%read-delimited! DELIMS BUF GOBBLE? [PORT START END])
+
+This returns a pair of values: (TERMINATOR . NUM-READ).
+- TERMINATOR describes why the read was terminated. If it is a
+ character or the eof object, then that is the value that terminated
+ the read. If it is #f, the function filled the buffer without finding
+ a delimiting character.
+- NUM-READ is the number of characters read into BUF.
+
+If the read is successfully terminated by reading a delimiter
+character, then the gobble? parameter determines what to do with the
+terminating character. If true, the character is removed from the
+input stream; if false, the character is left in the input stream
+where a subsequent read operation will retrieve it. In either case,
+the character is also the first value returned by the procedure call.
+
+(The descriptions of this function was borrowed from the SCSH manual,
+by Olin Shivers and Brian Carlstrom.)
+
+*** The `read-line' and `read-line!' functions have changed; they now
+trim the terminator by default; previously they appended it to the
+returned string. For the old behavior, use (read-line PORT 'concat).
+
+*** The functions `uniform-array-read!' and `uniform-array-write!' now
+take new optional START and END arguments, specifying the region of
+the array to read and write.
+
+*** The `ungetc-char-ready?' function has been removed. We feel it's
+inappropriate for an interface to expose implementation details this
+way.
+
+** Changes to the Unix library and system call interface
+
+*** The new fcntl function provides access to the Unix `fcntl' system
+call.
+
+(fcntl PORT COMMAND VALUE)
+ Apply COMMAND to PORT's file descriptor, with VALUE as an argument.
+ Values for COMMAND are:
+
+ F_DUPFD duplicate a file descriptor
+ F_GETFD read the descriptor's close-on-exec flag
+ F_SETFD set the descriptor's close-on-exec flag to VALUE
+ F_GETFL read the descriptor's flags, as set on open
+ F_SETFL set the descriptor's flags, as set on open to VALUE
+ F_GETOWN return the process ID of a socket's owner, for SIGIO
+ F_SETOWN set the process that owns a socket to VALUE, for SIGIO
+ FD_CLOEXEC not sure what this is
+
+For details, see the documentation for the fcntl system call.
+
+*** The arguments to `select' have changed, for compatibility with
+SCSH. The TIMEOUT parameter may now be non-integral, yielding the
+expected behavior. The MILLISECONDS parameter has been changed to
+MICROSECONDS, to more closely resemble the underlying system call.
+The RVEC, WVEC, and EVEC arguments can now be vectors; the type of the
+corresponding return set will be the same.
+
+*** The arguments to the `mknod' system call have changed. They are
+now:
+
+(mknod PATH TYPE PERMS DEV)
+ Create a new file (`node') in the file system. PATH is the name of
+ the file to create. TYPE is the kind of file to create; it should
+ be 'fifo, 'block-special, or 'char-special. PERMS specifies the
+ permission bits to give the newly created file. If TYPE is
+ 'block-special or 'char-special, DEV specifies which device the
+ special file refers to; its interpretation depends on the kind of
+ special file being created.
+
+*** The `fork' function has been renamed to `primitive-fork', to avoid
+clashing with various SCSH forks.
+
+*** The `recv' and `recvfrom' functions have been renamed to `recv!'
+and `recvfrom!'. They no longer accept a size for a second argument;
+you must pass a string to hold the received value. They no longer
+return the buffer. Instead, `recv' returns the length of the message
+received, and `recvfrom' returns a pair containing the packet's length
+and originating address.
+
+*** The file descriptor datatype has been removed, as have the
+`read-fd', `write-fd', `close', `lseek', and `dup' functions.
+We plan to replace these functions with a SCSH-compatible interface.
+
+*** The `create' function has been removed; it's just a special case
+of `open'.
+
+*** There are new functions to break down process termination status
+values. In the descriptions below, STATUS is a value returned by
+`waitpid'.
+
+(status:exit-val STATUS)
+ If the child process exited normally, this function returns the exit
+ code for the child process (i.e., the value passed to exit, or
+ returned from main). If the child process did not exit normally,
+ this function returns #f.
+
+(status:stop-sig STATUS)
+ If the child process was suspended by a signal, this function
+ returns the signal that suspended the child. Otherwise, it returns
+ #f.
+
+(status:term-sig STATUS)
+ If the child process terminated abnormally, this function returns
+ the signal that terminated the child. Otherwise, this function
+ returns false.
+
+POSIX promises that exactly one of these functions will return true on
+a valid STATUS value.
+
+These functions are compatible with SCSH.
+
+*** There are new accessors and setters for the broken-out time vectors
+returned by `localtime', `gmtime', and that ilk. They are:
+
+ Component Accessor Setter
+ ========================= ============ ============
+ seconds tm:sec set-tm:sec
+ minutes tm:min set-tm:min
+ hours tm:hour set-tm:hour
+ day of the month tm:mday set-tm:mday
+ month tm:mon set-tm:mon
+ year tm:year set-tm:year
+ day of the week tm:wday set-tm:wday
+ day in the year tm:yday set-tm:yday
+ daylight saving time tm:isdst set-tm:isdst
+ GMT offset, seconds tm:gmtoff set-tm:gmtoff
+ name of time zone tm:zone set-tm:zone
+
+*** There are new accessors for the vectors returned by `uname',
+describing the host system:
+
+ Component Accessor
+ ============================================== ================
+ name of the operating system implementation utsname:sysname
+ network name of this machine utsname:nodename
+ release level of the operating system utsname:release
+ version level of the operating system utsname:version
+ machine hardware platform utsname:machine
+
+*** There are new accessors for the vectors returned by `getpw',
+`getpwnam', `getpwuid', and `getpwent', describing entries from the
+system's user database:
+
+ Component Accessor
+ ====================== =================
+ user name passwd:name
+ user password passwd:passwd
+ user id passwd:uid
+ group id passwd:gid
+ real name passwd:gecos
+ home directory passwd:dir
+ shell program passwd:shell
+
+*** There are new accessors for the vectors returned by `getgr',
+`getgrnam', `getgrgid', and `getgrent', describing entries from the
+system's group database:
+
+ Component Accessor
+ ======================= ============
+ group name group:name
+ group password group:passwd
+ group id group:gid
+ group members group:mem
+
+*** There are new accessors for the vectors returned by `gethost',
+`gethostbyaddr', `gethostbyname', and `gethostent', describing
+internet hosts:
+
+ Component Accessor
+ ========================= ===============
+ official name of host hostent:name
+ alias list hostent:aliases
+ host address type hostent:addrtype
+ length of address hostent:length
+ list of addresses hostent:addr-list
+
+*** There are new accessors for the vectors returned by `getnet',
+`getnetbyaddr', `getnetbyname', and `getnetent', describing internet
+networks:
+
+ Component Accessor
+ ========================= ===============
+ official name of net netent:name
+ alias list netent:aliases
+ net number type netent:addrtype
+ net number netent:net
+
+*** There are new accessors for the vectors returned by `getproto',
+`getprotobyname', `getprotobynumber', and `getprotoent', describing
+internet protocols:
+
+ Component Accessor
+ ========================= ===============
+ official protocol name protoent:name
+ alias list protoent:aliases
+ protocol number protoent:proto
+
+*** There are new accessors for the vectors returned by `getserv',
+`getservbyname', `getservbyport', and `getservent', describing
+internet protocols:
+
+ Component Accessor
+ ========================= ===============
+ official service name servent:name
+ alias list servent:aliases
+ port number servent:port
+ protocol to use servent:proto
+
+*** There are new accessors for the sockaddr structures returned by
+`accept', `getsockname', `getpeername', `recvfrom!':
+
+ Component Accessor
+ ======================================== ===============
+ address format (`family') sockaddr:fam
+ path, for file domain addresses sockaddr:path
+ address, for internet domain addresses sockaddr:addr
+ TCP or UDP port, for internet sockaddr:port
+
+*** The `getpwent', `getgrent', `gethostent', `getnetent',
+`getprotoent', and `getservent' functions now return #f at the end of
+the user database. (They used to throw an exception.)
+
+Note that calling MUMBLEent function is equivalent to calling the
+corresponding MUMBLE function with no arguments.
+
+*** The `setpwent', `setgrent', `sethostent', `setnetent',
+`setprotoent', and `setservent' routines now take no arguments.
+
+*** The `gethost', `getproto', `getnet', and `getserv' functions now
+provide more useful information when they throw an exception.
+
+*** The `lnaof' function has been renamed to `inet-lnaof'.
+
+*** Guile now claims to have the `current-time' feature.
+
+*** The `mktime' function now takes an optional second argument ZONE,
+giving the time zone to use for the conversion. ZONE should be a
+string, in the same format as expected for the "TZ" environment variable.
+
+*** The `strptime' function now returns a pair (TIME . COUNT), where
+TIME is the parsed time as a vector, and COUNT is the number of
+characters from the string left unparsed. This function used to
+return the remaining characters as a string.
+
+*** The `gettimeofday' function has replaced the old `time+ticks' function.
+The return value is now (SECONDS . MICROSECONDS); the fractional
+component is no longer expressed in "ticks".
+
+*** The `ticks/sec' constant has been removed, in light of the above change.
+
+* Changes to the gh_ interface
+
+** gh_eval_str() now returns an SCM object which is the result of the
+evaluation
+
+** gh_scm2str() now copies the Scheme data to a caller-provided C
+array
+
+** gh_scm2newstr() now makes a C array, copies the Scheme data to it,
+and returns the array
+
+** gh_scm2str0() is gone: there is no need to distinguish
+null-terminated from non-null-terminated, since gh_scm2newstr() allows
+the user to interpret the data both ways.
+
+* Changes to the scm_ interface
+
+** The new function scm_symbol_value0 provides an easy way to get a
+symbol's value from C code:
+
+SCM scm_symbol_value0 (char *NAME)
+ Return the value of the symbol named by the null-terminated string
+ NAME in the current module. If the symbol named NAME is unbound in
+ the current module, return SCM_UNDEFINED.
+
+** The new function scm_sysintern0 creates new top-level variables,
+without assigning them a value.
+
+SCM scm_sysintern0 (char *NAME)
+ Create a new Scheme top-level variable named NAME. NAME is a
+ null-terminated string. Return the variable's value cell.
+
+** The function scm_internal_catch is the guts of catch. It handles
+all the mechanics of setting up a catch target, invoking the catch
+body, and perhaps invoking the handler if the body does a throw.
+
+The function is designed to be usable from C code, but is general
+enough to implement all the semantics Guile Scheme expects from throw.
+
+TAG is the catch tag. Typically, this is a symbol, but this function
+doesn't actually care about that.
+
+BODY is a pointer to a C function which runs the body of the catch;
+this is the code you can throw from. We call it like this:
+ BODY (BODY_DATA, JMPBUF)
+where:
+ BODY_DATA is just the BODY_DATA argument we received; we pass it
+ through to BODY as its first argument. The caller can make
+ BODY_DATA point to anything useful that BODY might need.
+ JMPBUF is the Scheme jmpbuf object corresponding to this catch,
+ which we have just created and initialized.
+
+HANDLER is a pointer to a C function to deal with a throw to TAG,
+should one occur. We call it like this:
+ HANDLER (HANDLER_DATA, THROWN_TAG, THROW_ARGS)
+where
+ HANDLER_DATA is the HANDLER_DATA argument we recevied; it's the
+ same idea as BODY_DATA above.
+ THROWN_TAG is the tag that the user threw to; usually this is
+ TAG, but it could be something else if TAG was #t (i.e., a
+ catch-all), or the user threw to a jmpbuf.
+ THROW_ARGS is the list of arguments the user passed to the THROW
+ function.
+
+BODY_DATA is just a pointer we pass through to BODY. HANDLER_DATA
+is just a pointer we pass through to HANDLER. We don't actually
+use either of those pointers otherwise ourselves. The idea is
+that, if our caller wants to communicate something to BODY or
+HANDLER, it can pass a pointer to it as MUMBLE_DATA, which BODY and
+HANDLER can then use. Think of it as a way to make BODY and
+HANDLER closures, not just functions; MUMBLE_DATA points to the
+enclosed variables.
+
+Of course, it's up to the caller to make sure that any data a
+MUMBLE_DATA needs is protected from GC. A common way to do this is
+to make MUMBLE_DATA a pointer to data stored in an automatic
+structure variable; since the collector must scan the stack for
+references anyway, this assures that any references in MUMBLE_DATA
+will be found.
+
+** The new function scm_internal_lazy_catch is exactly like
+scm_internal_catch, except:
+
+- It does not unwind the stack (this is the major difference).
+- If handler returns, its value is returned from the throw.
+- BODY always receives #f as its JMPBUF argument (since there's no
+ jmpbuf associated with a lazy catch, because we don't unwind the
+ stack.)
+
+** scm_body_thunk is a new body function you can pass to
+scm_internal_catch if you want the body to be like Scheme's `catch'
+--- a thunk, or a function of one argument if the tag is #f.
+
+BODY_DATA is a pointer to a scm_body_thunk_data structure, which
+contains the Scheme procedure to invoke as the body, and the tag
+we're catching. If the tag is #f, then we pass JMPBUF (created by
+scm_internal_catch) to the body procedure; otherwise, the body gets
+no arguments.
+
+** scm_handle_by_proc is a new handler function you can pass to
+scm_internal_catch if you want the handler to act like Scheme's catch
+--- call a procedure with the tag and the throw arguments.
+
+If the user does a throw to this catch, this function runs a handler
+procedure written in Scheme. HANDLER_DATA is a pointer to an SCM
+variable holding the Scheme procedure object to invoke. It ought to
+be a pointer to an automatic variable (i.e., one living on the stack),
+or the procedure object should be otherwise protected from GC.
+
+** scm_handle_by_message is a new handler function to use with
+`scm_internal_catch' if you want Guile to print a message and die.
+It's useful for dealing with throws to uncaught keys at the top level.
+
+HANDLER_DATA, if non-zero, is assumed to be a char * pointing to a
+message header to print; if zero, we use "guile" instead. That
+text is followed by a colon, then the message described by ARGS.
+
+** The return type of scm_boot_guile is now void; the function does
+not return a value, and indeed, never returns at all.
+
+** The new function scm_shell makes it easy for user applications to
+process command-line arguments in a way that is compatible with the
+stand-alone guile interpreter (which is in turn compatible with SCSH,
+the Scheme shell).
+
+To use the scm_shell function, first initialize any guile modules
+linked into your application, and then call scm_shell with the values
+of ARGC and ARGV your `main' function received. scm_shell will adding
+any SCSH-style meta-arguments from the top of the script file to the
+argument vector, and then process the command-line arguments. This
+generally means loading a script file or starting up an interactive
+command interpreter. For details, see "Changes to the stand-alone
+interpreter" above.
+
+** The new functions scm_get_meta_args and scm_count_argv help you
+implement the SCSH-style meta-argument, `\'.
+
+char **scm_get_meta_args (int ARGC, char **ARGV)
+ If the second element of ARGV is a string consisting of a single
+ backslash character (i.e. "\\" in Scheme notation), open the file
+ named by the following argument, parse arguments from it, and return
+ the spliced command line. The returned array is terminated by a
+ null pointer.
+
+ For details of argument parsing, see above, under "guile now accepts
+ command-line arguments compatible with SCSH..."
+
+int scm_count_argv (char **ARGV)
+ Count the arguments in ARGV, assuming it is terminated by a null
+ pointer.
+
+For an example of how these functions might be used, see the source
+code for the function scm_shell in libguile/script.c.
+
+You will usually want to use scm_shell instead of calling this
+function yourself.
+
+** The new function scm_compile_shell_switches turns an array of
+command-line arguments into Scheme code to carry out the actions they
+describe. Given ARGC and ARGV, it returns a Scheme expression to
+evaluate, and calls scm_set_program_arguments to make any remaining
+command-line arguments available to the Scheme code. For example,
+given the following arguments:
+
+ -e main -s ekko a speckled gecko
+
+scm_set_program_arguments will return the following expression:
+
+ (begin (load "ekko") (main (command-line)) (quit))
+
+You will usually want to use scm_shell instead of calling this
+function yourself.
+
+** The function scm_shell_usage prints a usage message appropriate for
+an interpreter that uses scm_compile_shell_switches to handle its
+command-line arguments.
+
+void scm_shell_usage (int FATAL, char *MESSAGE)
+ Print a usage message to the standard error output. If MESSAGE is
+ non-zero, write it before the usage message, followed by a newline.
+ If FATAL is non-zero, exit the process, using FATAL as the
+ termination status. (If you want to be compatible with Guile,
+ always use 1 as the exit status when terminating due to command-line
+ usage problems.)
+
+You will usually want to use scm_shell instead of calling this
+function yourself.
+
+** scm_eval_0str now returns SCM_UNSPECIFIED if the string contains no
+expressions. It used to return SCM_EOL. Earth-shattering.
+
+** The macros for declaring scheme objects in C code have been
+rearranged slightly. They are now:
+
+SCM_SYMBOL (C_NAME, SCHEME_NAME)
+ Declare a static SCM variable named C_NAME, and initialize it to
+ point to the Scheme symbol whose name is SCHEME_NAME. C_NAME should
+ be a C identifier, and SCHEME_NAME should be a C string.
+
+SCM_GLOBAL_SYMBOL (C_NAME, SCHEME_NAME)
+ Just like SCM_SYMBOL, but make C_NAME globally visible.
+
+SCM_VCELL (C_NAME, SCHEME_NAME)
+ Create a global variable at the Scheme level named SCHEME_NAME.
+ Declare a static SCM variable named C_NAME, and initialize it to
+ point to the Scheme variable's value cell.
+
+SCM_GLOBAL_VCELL (C_NAME, SCHEME_NAME)
+ Just like SCM_VCELL, but make C_NAME globally visible.
+
+The `guile-snarf' script writes initialization code for these macros
+to its standard output, given C source code as input.
+
+The SCM_GLOBAL macro is gone.
+
+** The scm_read_line and scm_read_line_x functions have been replaced
+by Scheme code based on the %read-delimited! procedure (known to C
+code as scm_read_delimited_x). See its description above for more
+information.
+
+** The function scm_sys_open has been renamed to scm_open. It now
+returns a port instead of an FD object.
+
+* The dynamic linking support has changed. For more information, see
+libguile/DYNAMIC-LINKING.
+
+\f
+Guile 1.0b3
+
+User-visible changes from Thursday, September 5, 1996 until Guile 1.0
+(Sun 5 Jan 1997):
+
+* Changes to the 'guile' program:
+
+** Guile now loads some new files when it starts up. Guile first
+searches the load path for init.scm, and loads it if found. Then, if
+Guile is not being used to execute a script, and the user's home
+directory contains a file named `.guile', Guile loads that.
+
+** You can now use Guile as a shell script interpreter.
To paraphrase the SCSH manual:
Note that some very old Unix systems don't support the `#!' syntax.
-* You can now run Guile without installing it.
+** You can now run Guile without installing it.
Previous versions of the interactive Guile interpreter (`guile')
couldn't start up unless Guile's Scheme library had been installed;
export SCHEME_LOAD_PATH=/home/jimb/my-scheme:/home/jimb/guile-1.0b3
-* Guile's header files should no longer conflict with your system's
+** Guile's read-eval-print loop no longer prints #<unspecified>
+results. If the user wants to see this, she can evaluate the
+expression (assert-repl-print-unspecified #t), perhaps in her startup
+file.
+
+** Guile no longer shows backtraces by default when an error occurs;
+however, it does display a message saying how to get one, and how to
+request that they be displayed by default. After an error, evaluate
+ (backtrace)
+to see a backtrace, and
+ (debug-enable 'backtrace)
+to see them by default.
+
+
+
+* Changes to Guile Scheme:
+
+** Guile now distinguishes between #f and the empty list.
+
+This is for compatibility with the IEEE standard, the (possibly)
+upcoming Revised^5 Report on Scheme, and many extant Scheme
+implementations.
+
+Guile used to have #f and '() denote the same object, to make Scheme's
+type system more compatible with Emacs Lisp's. However, the change
+caused too much trouble for Scheme programmers, and we found another
+way to reconcile Emacs Lisp with Scheme that didn't require this.
+
+
+** Guile's delq, delv, delete functions, and their destructive
+counterparts, delq!, delv!, and delete!, now remove all matching
+elements from the list, not just the first. This matches the behavior
+of the corresponding Emacs Lisp functions, and (I believe) the Maclisp
+functions which inspired them.
+
+I recognize that this change may break code in subtle ways, but it
+seems best to make the change before the FSF's first Guile release,
+rather than after.
+
+
+** The compiled-library-path function has been deleted from libguile.
+
+** The facilities for loading Scheme source files have changed.
+
+*** The variable %load-path now tells Guile which directories to search
+for Scheme code. Its value is a list of strings, each of which names
+a directory.
+
+*** The variable %load-extensions now tells Guile which extensions to
+try appending to a filename when searching the load path. Its value
+is a list of strings. Its default value is ("" ".scm").
+
+*** (%search-load-path FILENAME) searches the directories listed in the
+value of the %load-path variable for a Scheme file named FILENAME,
+with all the extensions listed in %load-extensions. If it finds a
+match, then it returns its full filename. If FILENAME is absolute, it
+returns it unchanged. Otherwise, it returns #f.
+
+%search-load-path will not return matches that refer to directories.
+
+*** (primitive-load FILENAME :optional CASE-INSENSITIVE-P SHARP)
+uses %seach-load-path to find a file named FILENAME, and loads it if
+it finds it. If it can't read FILENAME for any reason, it throws an
+error.
+
+The arguments CASE-INSENSITIVE-P and SHARP are interpreted as by the
+`read' function.
+
+*** load uses the same searching semantics as primitive-load.
+
+*** The functions %try-load, try-load-with-path, %load, load-with-path,
+basic-try-load-with-path, basic-load-with-path, try-load-module-with-
+path, and load-module-with-path have been deleted. The functions
+above should serve their purposes.
+
+*** If the value of the variable %load-hook is a procedure,
+`primitive-load' applies its value to the name of the file being
+loaded (without the load path directory name prepended). If its value
+is #f, it is ignored. Otherwise, an error occurs.
+
+This is mostly useful for printing load notification messages.
+
+
+** The function `eval!' is no longer accessible from the scheme level.
+We can't allow operations which introduce glocs into the scheme level,
+because Guile's type system can't handle these as data. Use `eval' or
+`read-and-eval!' (see below) as replacement.
+
+** The new function read-and-eval! reads an expression from PORT,
+evaluates it, and returns the result. This is more efficient than
+simply calling `read' and `eval', since it is not necessary to make a
+copy of the expression for the evaluator to munge.
+
+Its optional arguments CASE_INSENSITIVE_P and SHARP are interpreted as
+for the `read' function.
+
+
+** The function `int?' has been removed; its definition was identical
+to that of `integer?'.
+
+** The functions `<?', `<?', `<=?', `=?', `>?', and `>=?'. Code should
+use the R4RS names for these functions.
+
+** The function object-properties no longer returns the hash handle;
+it simply returns the object's property list.
+
+** Many functions have been changed to throw errors, instead of
+returning #f on failure. The point of providing exception handling in
+the language is to simplify the logic of user code, but this is less
+useful if Guile's primitives don't throw exceptions.
+
+** The function `fileno' has been renamed from `%fileno'.
+
+** The function primitive-mode->fdes returns #t or #f now, not 1 or 0.
+
+
+* Changes to Guile's C interface:
+
+** The library's initialization procedure has been simplified.
+scm_boot_guile now has the prototype:
+
+void scm_boot_guile (int ARGC,
+ char **ARGV,
+ void (*main_func) (),
+ void *closure);
+
+scm_boot_guile calls MAIN_FUNC, passing it CLOSURE, ARGC, and ARGV.
+MAIN_FUNC should do all the work of the program (initializing other
+packages, reading user input, etc.) before returning. When MAIN_FUNC
+returns, call exit (0); this function never returns. If you want some
+other exit value, MAIN_FUNC may call exit itself.
+
+scm_boot_guile arranges for program-arguments to return the strings
+given by ARGC and ARGV. If MAIN_FUNC modifies ARGC/ARGV, should call
+scm_set_program_arguments with the final list, so Scheme code will
+know which arguments have been processed.
+
+scm_boot_guile establishes a catch-all catch handler which prints an
+error message and exits the process. This means that Guile exits in a
+coherent way when system errors occur and the user isn't prepared to
+handle it. If the user doesn't like this behavior, they can establish
+their own universal catcher in MAIN_FUNC to shadow this one.
+
+Why must the caller do all the real work from MAIN_FUNC? The garbage
+collector assumes that all local variables of type SCM will be above
+scm_boot_guile's stack frame on the stack. If you try to manipulate
+SCM values after this function returns, it's the luck of the draw
+whether the GC will be able to find the objects you allocate. So,
+scm_boot_guile function exits, rather than returning, to discourage
+people from making that mistake.
+
+The IN, OUT, and ERR arguments were removed; there are other
+convenient ways to override these when desired.
+
+The RESULT argument was deleted; this function should never return.
+
+The BOOT_CMD argument was deleted; the MAIN_FUNC argument is more
+general.
+
+
+** Guile's header files should no longer conflict with your system's
header files.
In order to compile code which #included <libguile.h>, previous
Guile's installation procedure puts libguile.h in $(includedir), and
the rest in $(includedir)/libguile.
-* Guile's delq, delv, delete functions, and their destructive
-counterparts, delq!, delv!, and delete!, now remove all matching
-elements from the list, not just the first. This matches the behavior
-of the corresponding Emacs Lisp functions, and (I believe) the Maclisp
-functions which inspired them.
-I recognize that this change may break code in subtle ways, but it
-seems best to make the change before the FSF's first Guile release,
-rather than after.
+** Two new C functions, scm_protect_object and scm_unprotect_object,
+have been added to the Guile library.
+scm_protect_object (OBJ) protects OBJ from the garbage collector.
+OBJ will not be freed, even if all other references are dropped,
+until someone does scm_unprotect_object (OBJ). Both functions
+return OBJ.
-* The compiled-library-path function has been deleted from libguile.
+Note that calls to scm_protect_object do not nest. You can call
+scm_protect_object any number of times on a given object, and the
+next call to scm_unprotect_object will unprotect it completely.
+Basically, scm_protect_object and scm_unprotect_object just
+maintain a list of references to things. Since the GC knows about
+this list, all objects it mentions stay alive. scm_protect_object
+adds its argument to the list; scm_unprotect_object remove its
+argument from the list.
-* A variable and two new functions have been added to libguile:
-** The variable %load-path now tells Guile which directories to search
-for Scheme code. Its value is a list of strings, each of which names
-a directory.
+** scm_eval_0str now returns the value of the last expression
+evaluated.
-** (%search-load-path FILENAME) searches the directories listed in the
-value of the %load-path variable for a Scheme file named FILENAME. If
-it finds a match, then it returns its full filename. Otherwise, it
-returns #f. %search-load-path will not return matches that refer to
-directories.
+** The new function scm_read_0str reads an s-expression from a
+null-terminated string, and returns it.
-** (%try-load-path FILENAME :optional CASE-INSENSITIVE-P SHARP)
-searches the directories listed in %load-path for a file named
-FILENAME, and loads it if it finds it. If it can't read FILENAME for
-any reason, it throws an error.
+** The new function `scm_stdio_to_port' converts a STDIO file pointer
+to a Scheme port object.
-The arguments CASE-INSENSITIVE-P and SHARP are interpreted as by the
-%try-load function.
+** The new function `scm_set_program_arguments' allows C code to set
+the value teruturned by the Scheme `program-arguments' function.
\f
Older changes:
\f
Copyright information:
-Copyright (C) 1996 Free Software Foundation, Inc.
+Copyright (C) 1996,1997 Free Software Foundation, Inc.
Permission is granted to anyone to make or distribute verbatim copies
of this document as received, in any medium, provided that the
under the above conditions, provided also that they
carry prominent notices stating who last changed them.
+\f
+Local variables:
+mode: outline
+paragraph-separate: "[ \f]*$"
+end:
+
HCoop / bpt / guile.git / blobdiff