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2082 lines
83 KiB
Text
2082 lines
83 KiB
Text
Guile NEWS --- history of user-visible changes. -*- text -*-
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Copyright (C) 1996, 1997 Free Software Foundation, Inc.
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See the end for copying conditions.
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Please send Guile bug reports to bug-guile@gnu.org.
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Changes since Guile 1.2:
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* Changes to the distribution
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** We renamed the SCHEME_LOAD_PATH environment variable to GUILE_LOAD_PATH.
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To avoid conflicts, programs should name environment variables after
|
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themselves, except when there's a common practice establishing some
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other convention.
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For now, Guile supports both GUILE_LOAD_PATH and SCHEME_LOAD_PATH,
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giving the former precedence, and printing a warning message if the
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||
latter is set. Guile 1.4 will not recognize SCHEME_LOAD_PATH at all.
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** The header files related to multi-byte characters have been removed.
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||
They were: libguile/extchrs.h and libguile/mbstrings.h. Any C code
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||
which referred to these explicitly will probably need to be rewritten,
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||
since the support for the variant string types has been removed; see
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below.
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** The header files append.h and sequences.h have been removed. These
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files implemented non-R4RS operations which would encourage
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non-portable programming style and less easy-to-read code.
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* Changes to the stand-alone interpreter
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** New procedures have been added to implement a "batch mode":
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*** Function: batch-mode?
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Returns a boolean indicating whether the interpreter is in batch
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mode.
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*** Function: set-batch-mode?! ARG
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If ARG is true, switches the interpreter to batch mode. The `#f'
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case has not been implemented.
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** Guile now provides full command-line editing, when run interactively.
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To use this feature, you must have the readline library installed.
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The Guile build process will notice it, and automatically include
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support for it.
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The readline library is available via anonymous FTP from any GNU
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mirror site; the canonical location is "ftp://prep.ai.mit.edu/pub/gnu".
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** the-last-stack is now a fluid.
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* Changes to the procedure for linking libguile with your programs
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** You can now use the 'build-guile' utility to link against Guile.
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Guile now includes a command-line utility called 'build-guile', which
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writes to its standard output a list of flags which you must pass to
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the linker to link against the Guile library. The flags include
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'-lguile' itself, and any other libraries the Guile library depends
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||
upon.
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For example, here is a Makefile rule that builds a program named 'foo'
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from the object files ${FOO_OBJECTS}, and links them against Guile:
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foo: ${FOO_OBJECTS}
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${CC} ${CFLAGS} ${FOO_OBJECTS} `build-guile link` -o foo
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Previous Guile releases recommended that you use autoconf to detect
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which of a predefined set of libraries were present on your system.
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It is more robust to use build-guile, since it records exactly which
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libraries the installed Guile library requires.
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* Changes to Scheme functions and syntax
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** Multi-byte strings have been removed, as have multi-byte and wide
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ports. We felt that these were the wrong approach to
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internationalization support.
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** New function: readline [PROMPT]
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Read a line from the terminal, and allow the user to edit it,
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prompting with PROMPT. READLINE provides a large set of Emacs-like
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editing commands, lets the user recall previously typed lines, and
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works on almost every kind of terminal, including dumb terminals.
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READLINE assumes that the cursor is at the beginning of the line when
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it is invoked. Thus, you can't print a prompt yourself, and then call
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READLINE; you need to package up your prompt as a string, pass it to
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the function, and let READLINE print the prompt itself. This is
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||
because READLINE needs to know the prompt's screen width.
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For Guile to provide this function, you must have the readline library
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installed on your system.
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See also ADD-HISTORY function.
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** New function: add-history STRING
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Add STRING as the most recent line in the history used by the READLINE
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command. READLINE does not add lines to the history itself; you must
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call ADD-HISTORY to make previous input available to the user.
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** macro-eval! is removed. Use local-eval instead.
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** Some magic has been added to the printer to better handle user
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written printing routines (like record printers, closure printers).
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The problem is that these user written routines must have access to
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the current `print-state' to be able to handle fancy things like
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detection of circular references. These print-states have to be
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passed to the builtin printing routines (display, write, etc) to
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properly continue the print chain.
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We didn't want to change all existing print code so that it
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explicitely passes thru a print state in addition to a port. Instead,
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we extented the possible values that the builtin printing routines
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accept as a `port'. In addition to a normal port, they now also take
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a pair of a normal port and a print-state. Printing will go to the
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port and the print-state will be used to control the detection of
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circular references, etc. If the builtin function does not care for a
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print-state, it is simply ignored.
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User written callbacks are now called with such a pair as their
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`port', but because every function now accepts this pair as a PORT
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argument, you don't have to worry about that. In fact, it is probably
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safest to not check for these pairs.
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However, it is sometimes necessary to continue a print chain on a
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different port, for example to get a intermediate string
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representation of the printed value, mangle that string somehow, and
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then to finally print the mangled string. Use the new function
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inherit-print-state OLD-PORT NEW-PORT
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for this. It constructs a new `port' that prints to NEW-PORT but
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inherits the print-state of OLD-PORT.
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** struct-vtable-offset renamed to vtable-offset-user
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** New constants: vtable-index-layout, vtable-index-vtable, vtable-index-printer
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** There is now a fourth (optional) argument to make-vtable-vtable and
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make-struct when constructing new types (vtables). This argument
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initializes field vtable-index-printer of the vtable.
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** The detection of circular references has been extended to structs.
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That is, a structure that -- in the process of being printed -- prints
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itself does not lead to infinite recursion.
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** There is now some basic support for fluids. Please read
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"libguile/fluid.h" to find out more. It is accessible from Scheme with
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the following functions and macros:
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Function: make-fluid
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Create a new fluid object. Fluids are not special variables or
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some other extension to the semantics of Scheme, but rather
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ordinary Scheme objects. You can store them into variables (that
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are still lexically scoped, of course) or into any other place you
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like. Every fluid has a initial value of `#f'.
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Function: fluid? OBJ
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Test whether OBJ is a fluid.
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Function: fluid-ref FLUID
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Function: fluid-set! FLUID VAL
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Access/modify the fluid FLUID. Modifications are only visible
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within the current dynamic root (that includes threads).
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Function: with-fluids* FLUIDS VALUES THUNK
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FLUIDS is a list of fluids and VALUES a corresponding list of
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values for these fluids. Before THUNK gets called the values are
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installed in the fluids and the old values of the fluids are
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saved in the VALUES list. When the flow of control leaves THUNK
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or reenters it, the values get swapped again. You might think of
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this as a `safe-fluid-excursion'. Note that the VALUES list is
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modified by `with-fluids*'.
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Macro: with-fluids ((FLUID VALUE) ...) FORM ...
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The same as `with-fluids*' but with a different syntax. It looks
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just like `let', but both FLUID and VALUE are evaluated. Remember,
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fluids are not special variables but ordinary objects. FLUID
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should evaluate to a fluid.
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** Changes to system call interfaces:
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*** close-port, close-input-port and close-output-port now return a
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boolean instead of an `unspecified' object. #t means that the port
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was successfully closed, while #f means it was already closed. It is
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also now possible for these procedures to raise an exception if an
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error occurs (some errors from write can be delayed until close.)
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*** the first argument to chmod, fcntl, ftell and fseek can now be a
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file descriptor.
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*** the third argument to fcntl is now optional.
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*** the first argument to chown can now be a file descriptor or a port.
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*** the argument to stat can now be a port.
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*** The following new procedures have been added (most use scsh
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interfaces):
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*** procedure: close PORT/FD
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Similar to close-port (*note close-port: Closing Ports.), but also
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works on file descriptors. A side effect of closing a file
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descriptor is that any ports using that file descriptor are moved
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to a different file descriptor and have their revealed counts set
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to zero.
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*** procedure: port->fdes PORT
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Returns the integer file descriptor underlying PORT. As a side
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effect the revealed count of PORT is incremented.
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*** procedure: fdes->ports FDES
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Returns a list of existing ports which have FDES as an underlying
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file descriptor, without changing their revealed counts.
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*** procedure: fdes->inport FDES
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Returns an existing input port which has FDES as its underlying
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file descriptor, if one exists, and increments its revealed count.
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Otherwise, returns a new input port with a revealed count of 1.
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*** procedure: fdes->outport FDES
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Returns an existing output port which has FDES as its underlying
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file descriptor, if one exists, and increments its revealed count.
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Otherwise, returns a new output port with a revealed count of 1.
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The next group of procedures perform a `dup2' system call, if NEWFD
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(an integer) is supplied, otherwise a `dup'. The file descriptor to be
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duplicated can be supplied as an integer or contained in a port. The
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type of value returned varies depending on which procedure is used.
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All procedures also have the side effect when performing `dup2' that
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any ports using NEWFD are moved to a different file descriptor and have
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their revealed counts set to zero.
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*** procedure: dup->fdes PORT/FD [NEWFD]
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Returns an integer file descriptor.
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*** procedure: dup->inport PORT/FD [NEWFD]
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Returns a new input port using the new file descriptor.
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*** procedure: dup->outport PORT/FD [NEWFD]
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Returns a new output port using the new file descriptor.
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*** procedure: dup PORT/FD [NEWFD]
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Returns a new port if PORT/FD is a port, with the same mode as the
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supplied port, otherwise returns an integer file descriptor.
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*** procedure: dup->port PORT/FD MODE [NEWFD]
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Returns a new port using the new file descriptor. MODE supplies a
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mode string for the port (*note open-file: File Ports.).
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*** procedure: setenv NAME VALUE
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Modifies the environment of the current process, which is also the
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default environment inherited by child processes.
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If VALUE is `#f', then NAME is removed from the environment.
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Otherwise, the string NAME=VALUE is added to the environment,
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replacing any existing string with name matching NAME.
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The return value is unspecified.
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*** procedure: truncate-file OBJ SIZE
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Truncates the file referred to by OBJ to at most SIZE bytes. OBJ
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can be a string containing a file name or an integer file
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descriptor or port open for output on the file. The underlying
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system calls are `truncate' and `ftruncate'.
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The return value is unspecified.
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*** procedure: setvbuf PORT MODE [SIZE]
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Set the buffering mode for PORT. MODE can be:
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`_IONBF'
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non-buffered
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`_IOLBF'
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line buffered
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`_IOFBF'
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block buffered, using a newly allocated buffer of SIZE bytes.
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However if SIZE is zero or unspecified, the port will be made
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non-buffered.
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This procedure should not be used after I/O has been performed with
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the port.
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Ports are usually block buffered by default, with a default buffer
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size. Procedures e.g., *Note open-file: File Ports, which accept a
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mode string allow `0' to be added to request an unbuffered port.
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*** procedure: fsync PORT/FD
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Copies any unwritten data for the specified output file descriptor
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to disk. If PORT/FD is a port, its buffer is flushed before the
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underlying file descriptor is fsync'd. The return value is
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unspecified.
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*** procedure: open-fdes PATH FLAGS [MODES]
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Similar to `open' but returns a file descriptor instead of a port.
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*** procedure: execle PATH ENV [ARG] ...
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Similar to `execl', but the environment of the new process is
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specified by ENV, which must be a list of strings as returned by
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the `environ' procedure.
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This procedure is currently implemented using the `execve' system
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call, but we call it `execle' because of its Scheme calling
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interface.
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*** procedure: strerror ERRNO
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Returns the Unix error message corresponding to ERRNO, an integer.
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*** procedure: primitive-exit [STATUS]
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Terminate the current process without unwinding the Scheme stack.
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This is would typically be useful after a fork. The exit status
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is STATUS if supplied, otherwise zero.
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*** procedure: times
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Returns an object with information about real and processor time.
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The following procedures accept such an object as an argument and
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return a selected component:
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`tms:clock'
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The current real time, expressed as time units relative to an
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arbitrary base.
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`tms:utime'
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The CPU time units used by the calling process.
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`tms:stime'
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The CPU time units used by the system on behalf of the
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calling process.
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`tms:cutime'
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The CPU time units used by terminated child processes of the
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calling process, whose status has been collected (e.g., using
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`waitpid').
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`tms:cstime'
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Similarly, the CPU times units used by the system on behalf of
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terminated child processes.
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** Removed: list-length
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** Removed: list-append, list-append!
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** Removed: list-reverse, list-reverse!
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** array-map renamed to array-map!
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** serial-array-map renamed to serial-array-map!
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* Changes to the gh_ interface
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** Function: void gh_write (SCM x)
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Write the printed representation of the scheme object x to the current
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output port. Corresponds to the scheme level `write'.
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** gh_list_length renamed to gh_length.
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** vector handling routines
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Several major changes. In particular, gh_vector() now resembles
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(vector ...) (with a caveat -- see manual), and gh_make_vector() now
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exists and behaves like (make-vector ...). gh_vset() and gh_vref()
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have been renamed gh_vector_set_x() and gh_vector_ref(). Some missing
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vector-related gh_ functions have been implemented.
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** pair and list routines
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Implemented several of the R4RS pair and list functions that were
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missing.
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** gh_scm2doubles, gh_doubles2scm, gh_doubles2dvect
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New function. Converts double arrays back and forth between Scheme
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and C.
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* Changes to the scm_ interface
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||
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** Function: int scm_internal_select (int fds,
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SELECT_TYPE *rfds,
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SELECT_TYPE *wfds,
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SELECT_TYPE *efds,
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struct timeval *timeout);
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||
|
||
This is a replacement for the `select' function provided by the OS.
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It enables I/O blocking and sleeping to happen for one cooperative
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thread without blocking other threads. It also avoids busy-loops in
|
||
these situations. It is intended that all I/O blocking and sleeping
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||
will finally go through this function. Currently, this function is
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||
only available on systems providing `gettimeofday' and `select'.
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** Function: SCM scm_internal_stack_catch (SCM tag,
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scm_catch_body_t body,
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void *body_data,
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scm_catch_handler_t handler,
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void *handler_data)
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||
A new sibling to the other two C level `catch' functions
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scm_internal_catch and scm_internal_lazy_catch. Use it if you want
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||
the stack to be saved automatically into the variable `the-last-stack'
|
||
(scm_the_last_stack_var) on error. This is necessary if you want to
|
||
use advanced error reporting, such as calling scm_display_error and
|
||
scm_display_backtrace. (They both take a stack object as argument.)
|
||
|
||
** Function: SCM scm_spawn_thread (scm_catch_body_t body,
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||
void *body_data,
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||
scm_catch_handler_t handler,
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void *handler_data)
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||
|
||
Spawns a new thread. It does a job similar to
|
||
scm_call_with_new_thread but takes arguments more suitable when
|
||
spawning threads from application C code.
|
||
|
||
** The hook scm_error_callback has been removed. It was originally
|
||
intended as a way for the user to install his own error handler. But
|
||
that method works badly since it intervenes between throw and catch,
|
||
thereby changing the semantics of expressions like (catch #t ...).
|
||
The correct way to do it is to use one of the C level catch functions
|
||
in throw.c: scm_internal_catch/lazy_catch/stack_catch.
|
||
|
||
** Removed functions:
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||
|
||
scm_obj_length, scm_list_length, scm_list_append, scm_list_append_x,
|
||
scm_list_reverse, scm_list_reverse_x
|
||
|
||
** New macros: SCM_LISTn where n is one of the integers 0-9.
|
||
|
||
These can be used for pretty list creation from C. The idea is taken
|
||
from Erick Gallesio's STk.
|
||
|
||
** scm_array_map renamed to scm_array_map_x
|
||
|
||
** mbstrings are now removed
|
||
|
||
This means that the type codes scm_tc7_mb_string and
|
||
scm_tc7_mb_substring has been removed.
|
||
|
||
** The macros SCM_TYP7D and SCM_TYP7SD has been removed.
|
||
|
||
** The macro SCM_TYP7S has taken the role of the old SCM_TYP7D
|
||
|
||
SCM_TYP7S now masks away the bit which distinguishes substrings from
|
||
strings.
|
||
|
||
** All genio functions changed names and interfaces; new functions are
|
||
scm_putc, scm_puts, scm_lfwrite, scm_getc, scm_ungetc, and
|
||
scm_do_read_line.
|
||
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||
|
||
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.
|
||
|
||
|
||
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.
|
||
|
||
** 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 add
|
||
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.
|
||
|
||
|
||
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:
|
||
|
||
When Unix tries to execute an executable file whose first two
|
||
characters are the `#!', it treats the file not as machine code to
|
||
be directly executed by the native processor, but as source code
|
||
to be executed by some interpreter. The interpreter to use is
|
||
specified immediately after the #! sequence on the first line of
|
||
the source file. The kernel reads in the name of the interpreter,
|
||
and executes that instead. It passes the interpreter the source
|
||
filename as its first argument, with the original arguments
|
||
following. Consult the Unix man page for the `exec' system call
|
||
for more information.
|
||
|
||
Now you can use Guile as an interpreter, using a mechanism which is a
|
||
compatible subset of that provided by SCSH.
|
||
|
||
Guile now recognizes a '-s' command line switch, whose argument is the
|
||
name of a file of Scheme code to load. It also treats the two
|
||
characters `#!' as the start of a comment, terminated by `!#'. Thus,
|
||
to make a file of Scheme code directly executable by Unix, insert the
|
||
following two lines at the top of the file:
|
||
|
||
#!/usr/local/bin/guile -s
|
||
!#
|
||
|
||
Guile treats the argument of the `-s' command-line switch as the name
|
||
of a file of Scheme code to load, and treats the sequence `#!' as the
|
||
start of a block comment, terminated by `!#'.
|
||
|
||
For example, here's a version of 'echo' written in Scheme:
|
||
|
||
#!/usr/local/bin/guile -s
|
||
!#
|
||
(let loop ((args (cdr (program-arguments))))
|
||
(if (pair? args)
|
||
(begin
|
||
(display (car args))
|
||
(if (pair? (cdr args))
|
||
(display " "))
|
||
(loop (cdr args)))))
|
||
(newline)
|
||
|
||
Why does `#!' start a block comment terminated by `!#', instead of the
|
||
end of the line? That is the notation SCSH uses, and although we
|
||
don't yet support the other SCSH features that motivate that choice,
|
||
we would like to be backward-compatible with any existing Guile
|
||
scripts once we do. Furthermore, if the path to Guile on your system
|
||
is too long for your kernel, you can start the script with this
|
||
horrible hack:
|
||
|
||
#!/bin/sh
|
||
exec /really/long/path/to/guile -s "$0" ${1+"$@"}
|
||
!#
|
||
|
||
Note that some very old Unix systems don't support the `#!' syntax.
|
||
|
||
|
||
** 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;
|
||
they used the value of the environment variable `SCHEME_LOAD_PATH'
|
||
later on in the startup process, but not to find the startup code
|
||
itself. Now Guile uses `SCHEME_LOAD_PATH' in all searches for Scheme
|
||
code.
|
||
|
||
To run Guile without installing it, build it in the normal way, and
|
||
then set the environment variable `SCHEME_LOAD_PATH' to a
|
||
colon-separated list of directories, including the top-level directory
|
||
of the Guile sources. For example, if you unpacked Guile so that the
|
||
full filename of this NEWS file is /home/jimb/guile-1.0b3/NEWS, then
|
||
you might say
|
||
|
||
export SCHEME_LOAD_PATH=/home/jimb/my-scheme:/home/jimb/guile-1.0b3
|
||
|
||
|
||
** 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
|
||
versions of Guile required you to add a directory containing all the
|
||
Guile header files to your #include path. This was a problem, since
|
||
Guile's header files have names which conflict with many systems'
|
||
header files.
|
||
|
||
Now only <libguile.h> need appear in your #include path; you must
|
||
refer to all Guile's other header files as <libguile/mumble.h>.
|
||
Guile's installation procedure puts libguile.h in $(includedir), and
|
||
the rest in $(includedir)/libguile.
|
||
|
||
|
||
** 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.
|
||
|
||
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.
|
||
|
||
|
||
** scm_eval_0str now returns the value of the last expression
|
||
evaluated.
|
||
|
||
** The new function scm_read_0str reads an s-expression from a
|
||
null-terminated string, and returns it.
|
||
|
||
** The new function `scm_stdio_to_port' converts a STDIO file pointer
|
||
to a Scheme port object.
|
||
|
||
** The new function `scm_set_program_arguments' allows C code to set
|
||
the value teruturned by the Scheme `program-arguments' function.
|
||
|
||
|
||
Older changes:
|
||
|
||
* Guile no longer includes sophisticated Tcl/Tk support.
|
||
|
||
The old Tcl/Tk support was unsatisfying to us, because it required the
|
||
user to link against the Tcl library, as well as Tk and Guile. The
|
||
interface was also un-lispy, in that it preserved Tcl/Tk's practice of
|
||
referring to widgets by names, rather than exporting widgets to Scheme
|
||
code as a special datatype.
|
||
|
||
In the Usenix Tk Developer's Workshop held in July 1996, the Tcl/Tk
|
||
maintainers described some very interesting changes in progress to the
|
||
Tcl/Tk internals, which would facilitate clean interfaces between lone
|
||
Tk and other interpreters --- even for garbage-collected languages
|
||
like Scheme. They expected the new Tk to be publicly available in the
|
||
fall of 1996.
|
||
|
||
Since it seems that Guile might soon have a new, cleaner interface to
|
||
lone Tk, and that the old Guile/Tk glue code would probably need to be
|
||
completely rewritten, we (Jim Blandy and Richard Stallman) have
|
||
decided not to support the old code. We'll spend the time instead on
|
||
a good interface to the newer Tk, as soon as it is available.
|
||
|
||
Until then, gtcltk-lib provides trivial, low-maintenance functionality.
|
||
|
||
|
||
Copyright information:
|
||
|
||
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
|
||
copyright notice and this permission notice are preserved,
|
||
thus giving the recipient permission to redistribute in turn.
|
||
|
||
Permission is granted to distribute modified versions
|
||
of this document, or of portions of it,
|
||
under the above conditions, provided also that they
|
||
carry prominent notices stating who last changed them.
|
||
|
||
|
||
Local variables:
|
||
mode: outline
|
||
paragraph-separate: "[ ]*$"
|
||
end:
|
||
|