view man/xemacs/regs.texi @ 5353:38e24b8be4ea

Improve the lexical scoping in #'block, #'return-from. lisp/ChangeLog addition: 2011-02-07 Aidan Kehoe <kehoea@parhasard.net> * bytecomp.el: * bytecomp.el (byte-compile-initial-macro-environment): Shadow `block', `return-from' here, we implement them differently when byte-compiling. * bytecomp.el (byte-compile-active-blocks): New. * bytecomp.el (byte-compile-block-1): New. * bytecomp.el (byte-compile-return-from-1): New. * bytecomp.el (return-from-1): New. * bytecomp.el (block-1): New. These are two aliases that exist to have their own associated byte-compile functions, which functions implement `block' and `return-from'. * cl-extra.el (cl-macroexpand-all): Fix a bug here when macros in the environment have been compiled. * cl-macs.el (block): * cl-macs.el (return): * cl-macs.el (return-from): Be more careful about lexical scope in these macros. * cl.el: * cl.el ('cl-block-wrapper): Removed. * cl.el ('cl-block-throw): Removed. These aren't needed in code generated by this XEmacs. They shouldn't be needed in code generated by XEmacs 21.4, but if it turns out the packages do need them, we can put them back. 2011-01-30 Mike Sperber <mike@xemacs.org> * font-lock.el (font-lock-fontify-pending-extents): Don't fail if `font-lock-mode' is unset, which can happen in the middle of `revert-buffer'. 2011-01-23 Aidan Kehoe <kehoea@parhasard.net> * cl-macs.el (delete): * cl-macs.el (delq): * cl-macs.el (remove): * cl-macs.el (remq): Don't use the compiler macro if these functions were given the wrong number of arguments, as happens in lisp-tests.el. * cl-seq.el (remove, remq): Removed. I added these to subr.el, and forgot to remove them from here. 2011-01-22 Aidan Kehoe <kehoea@parhasard.net> * bytecomp.el (byte-compile-setq, byte-compile-set): Remove kludge allowing keywords' values to be set, all the code that does that is gone. * cl-compat.el (elt-satisfies-test-p): * faces.el (set-face-parent): * faces.el (face-doc-string): * gtk-font-menu.el: * gtk-font-menu.el (gtk-reset-device-font-menus): * msw-font-menu.el: * msw-font-menu.el (mswindows-reset-device-font-menus): * package-get.el (package-get-installedp): * select.el (select-convert-from-image-data): * sound.el: * sound.el (load-sound-file): * x-font-menu.el (x-reset-device-font-menus-core): Don't quote keywords, they're self-quoting, and the win from backward-compatibility is sufficiently small now that the style problem overrides it. 2011-01-22 Aidan Kehoe <kehoea@parhasard.net> * cl-macs.el (block, return-from): Require that NAME be a symbol in these macros, as always documented in the #'block docstring and as required by Common Lisp. * descr-text.el (unidata-initialize-unihan-database): Correct the use of non-symbols in #'block and #'return-from in this function. 2011-01-15 Aidan Kehoe <kehoea@parhasard.net> * cl-extra.el (concatenate): Accept more complicated TYPEs in this function, handing the sequences over to #'coerce if we don't understand them here. * cl-macs.el (inline): Don't proclaim #'concatenate as inline, its compiler macro is more useful than doing that. 2011-01-11 Aidan Kehoe <kehoea@parhasard.net> * subr.el (delete, delq, remove, remq): Move #'remove, #'remq here, they don't belong in cl-seq.el; move #'delete, #'delq here from fns.c, implement them in terms of #'delete*, allowing support for sequences generally. * update-elc.el (do-autoload-commands): Use #'delete*, not #'delq here, now the latter's no longer dumped. * cl-macs.el (delete, delq): Add compiler macros transforming #'delete and #'delq to #'delete* calls. 2011-01-10 Aidan Kehoe <kehoea@parhasard.net> * dialog.el (make-dialog-box): Correct a misplaced parenthesis here, thank you Mats Lidell in 87zkr9gqrh.fsf@mail.contactor.se ! 2011-01-02 Aidan Kehoe <kehoea@parhasard.net> * dialog.el (make-dialog-box): * list-mode.el (display-completion-list): These functions used to use cl-parsing-keywords; change them to use defun* instead, fixing the build. (Not sure what led to me not including this change in d1b17a33450b!) 2011-01-02 Aidan Kehoe <kehoea@parhasard.net> * cl-macs.el (define-star-compiler-macros): Make sure the form has ITEM and LIST specified before attempting to change to calls with explicit tests; necessary for some tests in lisp-tests.el to compile correctly. (stable-union, stable-intersection): Add compiler macros for these functions, in the same way we do for most of the other functions in cl-seq.el. 2011-01-01 Aidan Kehoe <kehoea@parhasard.net> * cl-macs.el (dolist, dotimes, do-symbols, macrolet) (symbol-macrolet): Define these macros with defmacro* instead of parsing the argument list by hand, for the sake of style and readability; use backquote where appropriate, instead of calling #'list and and friends, for the same reason. 2010-12-30 Aidan Kehoe <kehoea@parhasard.net> * x-misc.el (device-x-display): Provide this function, documented in the Lispref for years, but not existing previously. Thank you Julian Bradfield, thank you Jeff Mincy. 2010-12-30 Aidan Kehoe <kehoea@parhasard.net> * cl-seq.el: Move the heavy lifting from this file to C. Dump the cl-parsing-keywords macro, but don't use defun* for the functions we define that do take keywords, dynamic scope lossage makes that not practical. * subr.el (sort, fillarray): Move these aliases here. (map-plist): #'nsublis is now built-in, but at this point #'eql isn't necessarily available as a test; use #'eq. * obsolete.el (cl-delete-duplicates): Make this available for old compiler macros and old code. (memql): Document that this is equivalent to #'member*, and worse. * cl.el (adjoin, subst): Removed. These are in C. 2010-12-30 Aidan Kehoe <kehoea@parhasard.net> * simple.el (assoc-ignore-case): Remove a duplicate definition of this function (it's already in subr.el). * iso8859-1.el (char-width): On non-Mule, make this function equivalent to that produced by (constantly 1), but preserve its docstring. * subr.el (subst-char-in-string): Define this in terms of #'substitute, #'nsubstitute. (string-width): Define this using #'reduce and #'char-width. (char-width): Give this a simpler definition, it makes far more sense to check for mule at load time and redefine, as we do in iso8859-1.el. (store-substring): Implement this in terms of #'replace, now #'replace is cheap. 2010-12-30 Aidan Kehoe <kehoea@parhasard.net> * update-elc.el (lisp-files-needed-for-byte-compilation) (lisp-files-needing-early-byte-compilation): cl-macs belongs in the former, not the latter, it is as fundamental as bytecomp.el. 2010-12-30 Aidan Kehoe <kehoea@parhasard.net> * cl.el: Provde the Common Lisp program-error, type-error as error symbols. This doesn't nearly go far enough for anyone using the Common Lisp errors. 2010-12-29 Aidan Kehoe <kehoea@parhasard.net> * cl-macs.el (delete-duplicates): If the form has an incorrect number of arguments, don't attempt a compiler macroexpansion. 2010-12-29 Aidan Kehoe <kehoea@parhasard.net> * cl-macs.el (cl-safe-expr-p): Forms that start with the symbol lambda are also safe. 2010-12-29 Aidan Kehoe <kehoea@parhasard.net> * cl-macs.el (= < > <= >=): For these functions' compiler macros, the optimisation is safe even if the first and the last arguments have side effects, since they're only used the once. 2010-12-29 Aidan Kehoe <kehoea@parhasard.net> * cl-macs.el (inline-side-effect-free-compiler-macros): Unroll a loop here at macro-expansion time, so these compiler macros are compiled. Use #'eql instead of #'eq in a couple of places for better style. 2010-12-29 Aidan Kehoe <kehoea@parhasard.net> * cl-extra.el (notany, notevery): Avoid some dynamic scope stupidity with local variable names in these functions, when they weren't prefixed with cl-; go into some more detail in the doc strings. 2010-12-29 Aidan Kehoe <kehoea@parhasard.net> * byte-optimize.el (side-effect-free-fns): #'remove, #'remq are free of side-effects. (side-effect-and-error-free-fns): Drop dot, dot-marker from the list. 2010-11-17 Aidan Kehoe <kehoea@parhasard.net> * cl-extra.el (coerce): In the argument list, name the first argument OBJECT, not X; the former name was always used in the doc string and is clearer. Handle vector type specifications which include the length of the target sequence, error if there's a mismatch. * cl-macs.el (cl-make-type-test): Handle type specifications starting with the symbol 'eql. 2010-11-14 Aidan Kehoe <kehoea@parhasard.net> * cl-macs.el (eql): Don't remove the byte-compile property of this symbol. That was necessary to override a bug in bytecomp.el where #'eql was confused with #'eq, which bug we no longer have. If neither expression is constant, don't attempt to handle the expression in this compiler macro, leave it to byte-compile-eql, which produces better code anyway. * bytecomp.el (eq): #'eql is not the function associated with the byte-eq byte code. (byte-compile-eql): Add an explicit compile method for this function, for cases where the cl-macs compiler macro hasn't reduced it to #'eq or #'equal. 2010-10-25 Aidan Kehoe <kehoea@parhasard.net> Add compiler macros and compilation sanity-checking for various functions that take keywords. * byte-optimize.el (side-effect-free-fns): #'symbol-value is side-effect free and not error free. * bytecomp.el (byte-compile-normal-call): Check keyword argument lists for sanity; store information about the positions where keyword arguments start using the new byte-compile-keyword-start property. * cl-macs.el (cl-const-expr-val): Take a new optional argument, cl-not-constant, defaulting to nil, in this function; return it if the expression is not constant. (cl-non-fixnum-number-p): Make this into a separate function, we want to pass it to #'every. (eql): Use it. (define-star-compiler-macros): Use the same code to generate the member*, assoc* and rassoc* compiler macros; special-case some code in #'add-to-list in subr.el. (remove, remq): Add compiler macros for these two functions, in preparation for #'remove being in C. (define-foo-if-compiler-macros): Transform (remove-if-not ...) calls to (remove ... :if-not) at compile time, which will be a real win once the latter is in C. (define-substitute-if-compiler-macros) (define-subst-if-compiler-macros): Similarly for these functions. (delete-duplicates): Change this compiler macro to use #'plists-equal; if we don't have information about the type of SEQUENCE at compile time, don't bother attempting to inline the call, the function will be in C soon enough. (equalp): Remove an old commented-out compiler macro for this, if we want to see it it's in version control. (subst-char-in-string): Transform this to a call to nsubstitute or nsubstitute, if that is appropriate. * cl.el (ldiff): Don't call setf here, this makes for a load-time dependency problem in cl-macs.el 2010-06-14 Stephen J. Turnbull <stephen@xemacs.org> * term/vt100.el: Refer to XEmacs, not GNU Emacs, in permissions. * term/bg-mouse.el: * term/sup-mouse.el: Put copyright notice in canonical "Copyright DATE AUTHOR" form. Refer to XEmacs, not GNU Emacs, in permissions. * site-load.el: Add permission boilerplate. * mule/canna-leim.el: * alist.el: Refer to XEmacs, not APEL/this program, in permissions. * mule/canna-leim.el: Remove my copyright, I've assigned it to the FSF. 2010-06-14 Stephen J. Turnbull <stephen@xemacs.org> * gtk.el: * gtk-widget-accessors.el: * gtk-package.el: * gtk-marshal.el: * gtk-compose.el: * gnome.el: Add copyright notice based on internal evidence. 2010-06-14 Stephen J. Turnbull <stephen@xemacs.org> * easymenu.el: Add reference to COPYING to permission notice. * gutter.el: * gutter-items.el: * menubar-items.el: Fix typo "Xmacs" in permissions notice. 2010-06-14 Stephen J. Turnbull <stephen@xemacs.org> * auto-save.el: * font.el: * fontconfig.el: * mule/kinsoku.el: Add "part of XEmacs" text to permission notice. 2010-10-14 Aidan Kehoe <kehoea@parhasard.net> * byte-optimize.el (side-effect-free-fns): * cl-macs.el (remf, getf): * cl-extra.el (tailp, cl-set-getf, cl-do-remf): * cl.el (ldiff, endp): Tighten up Common Lisp compatibility for #'ldiff, #'endp, #'tailp; add circularity checking for the first two. #'cl-set-getf and #'cl-do-remf were Lisp implementations of #'plist-put and #'plist-remprop; change the names to aliases, changes the macros that use them to using #'plist-put and #'plist-remprop directly. 2010-10-12 Aidan Kehoe <kehoea@parhasard.net> * abbrev.el (fundamental-mode-abbrev-table, global-abbrev-table): Create both these abbrev tables using the usual #'define-abbrev-table calls, rather than attempting to special-case them. * cl-extra.el: Force cl-macs to be loaded here, if cl-extra.el is being loaded interpreted. Previously other, later files would redundantly call (load "cl-macs") when interpreted, it's more reasonable to do it here, once. * cmdloop.el (read-quoted-char-radix): Use defcustom here, we don't have any dump-order dependencies that would prevent that. * custom.el (eval-when-compile): Don't load cl-macs when interpreted or when byte-compiling, rely on cl-extra.el in the former case and the appropriate entry in bytecomp-load-hook in the latter. Get rid of custom-declare-variable-list, we have no dump-time dependencies that would require it. * faces.el (eval-when-compile): Don't load cl-macs when interpreted or when byte-compiling. * packages.el: Remove some inaccurate comments. * post-gc.el (cleanup-simple-finalizers): Use #'delete-if-not here, now the order of preloaded-file-list has been changed to make it available. * subr.el (custom-declare-variable-list): Remove. No need for it. Also remove a stub define-abbrev-table from this file, given the current order of preloaded-file-list there's no need for it. 2010-10-10 Aidan Kehoe <kehoea@parhasard.net> * bytecomp.el (byte-compile-constp) Forms quoted with FUNCTION are also constant. (byte-compile-initial-macro-environment): In #'the, if FORM is constant and does not match TYPE, warn at byte-compile time. 2010-10-10 Aidan Kehoe <kehoea@parhasard.net> * backquote.el (bq-vector-contents, bq-list*): Remove; the former is equivalent to (append VECTOR nil), the latter to (list* ...). (bq-process-2): Use (append VECTOR nil) instead of using #'bq-vector-contents to convert to a list. (bq-process-1): Now we use list* instead of bq-list * subr.el (list*): Moved from cl.el, since it is now required to be available the first time a backquoted form is encountered. * cl.el (list*): Move to subr.el. 2010-09-16 Aidan Kehoe <kehoea@parhasard.net> * test-harness.el (Check-Message): Add an omitted comma here, thank you the buildbot. 2010-09-16 Aidan Kehoe <kehoea@parhasard.net> * hash-table.el (hash-table-key-list, hash-table-value-list) (hash-table-key-value-alist, hash-table-key-value-plist): Remove some useless #'nreverse calls in these files; our hash tables have no order, it's not helpful to pretend they do. * behavior.el (read-behavior): Do the same in this file, in some code evidently copied from hash-table.el. 2010-09-16 Aidan Kehoe <kehoea@parhasard.net> * info.el (Info-insert-dir): * format.el (format-deannotate-region): * files.el (cd, save-buffers-kill-emacs): Use #'some, #'every and related functions for applying boolean operations to lists, instead of rolling our own ones that cons and don't short-circuit. 2010-09-16 Aidan Kehoe <kehoea@parhasard.net> * bytecomp.el (byte-compile-initial-macro-environment): * cl-macs.el (the): Rephrase the docstring, make its implementation when compiling files a little nicer. 2010-09-16 Aidan Kehoe <kehoea@parhasard.net> * descr-text.el (unidata-initialize-unicodedata-database) (unidata-initialize-unihan-database, describe-char-unicode-data) (describe-char-unicode-data): Wrap calls to the database functions with (with-fboundp ...), avoiding byte compile warnings on builds without support for the database functions. (describe-char): (reduce #'max ...), not (apply #'max ...), no need to cons needlessly. (describe-char): Remove a redundant lambda wrapping #'extent-properties. (describe-char-unicode-data): Call #'nsubst when replacing "" with nil in the result of #'split-string, instead of consing inside mapcar. 2010-09-16 Aidan Kehoe <kehoea@parhasard.net> * x-faces.el (x-available-font-sizes): * specifier.el (let-specifier): * package-ui.el (pui-add-required-packages): * msw-faces.el (mswindows-available-font-sizes): * modeline.el (modeline-minor-mode-menu): * minibuf.el (minibuf-directory-files): Replace the O2N (delq nil (mapcar (lambda (W) (and X Y)) Z)) with the ON (mapcan (lambda (W) (and X (list Y))) Z) in these files. 2010-09-16 Aidan Kehoe <kehoea@parhasard.net> * cl-macs.el (= < > <= >=): When these functions are handed more than two arguments, and those arguments have no side effects, transform to a series of two argument calls, avoiding funcall in the byte-compiled code. * mule/mule-cmds.el (finish-set-language-environment): Take advantage of this change in a function called 256 times at startup. 2010-09-16 Aidan Kehoe <kehoea@parhasard.net> * bytecomp.el (byte-compile-function-form, byte-compile-quote) (byte-compile-quote-form): Warn at compile time, and error at runtime, if a (quote ...) or a (function ...) form attempts to quote more than one object. 2010-09-16 Aidan Kehoe <kehoea@parhasard.net> * byte-optimize.el (byte-optimize-apply): Transform (apply 'nconc (mapcar ...)) to (mapcan ...); warn about use of the first idiom. * update-elc.el (do-autoload-commands): * packages.el (packages-find-package-library-path): * frame.el (frame-list): * extents.el (extent-descendants): * etags.el (buffer-tag-table-files): * dumped-lisp.el (preloaded-file-list): * device.el (device-list): * bytecomp-runtime.el (proclaim-inline, proclaim-notinline) Use #'mapcan, not (apply #'nconc (mapcar ...) in all these files. * bytecomp-runtime.el (eval-when-compile, eval-and-compile): In passing, mention that these macros also evaluate the body when interpreted. tests/ChangeLog addition: 2011-02-07 Aidan Kehoe <kehoea@parhasard.net> * automated/lisp-tests.el: Test lexical scope for `block', `return-from'; add a Known-Bug-Expect-Failure for a contorted example that fails when byte-compiled.
author Aidan Kehoe <kehoea@parhasard.net>
date Mon, 07 Feb 2011 12:01:24 +0000
parents 74fd4e045ea6
children 697ef44129c6
line wrap: on
line source


@node Registers, Display, Rectangles, Top
@chapter Registers
@cindex registers

  XEmacs @dfn{registers} are places in which you can save text or
positions for later use.  Once you save text or a rectangle in a
register, you can copy it into the buffer once or many times; a position
saved in a register is used by moving point to that position.
Rectangles can also be copied into and out of registers
(@pxref{Rectangles}).

@findex view-register
  Each register has a name which is a single character.  A register can
store a piece of text, a rectangle, a position, a window configuration,
or a file name, but only one thing at any given time.  Whatever you
store in a register remains there until you store something else in that
register.  To see what a register @var{r} contains, use @kbd{M-x
view-register}.

@table @kbd
@item M-x view-register @key{RET} @var{r}
Display a description of what register @var{r} contains.
@end table

@findex view-register
  @kbd{M-x view-register} reads a register name as an argument and then
displays the contents of the specified register.

@menu
* Position: RegPos.           Saving positions in registers.
* Text: RegText.              Saving text in registers.
* Rectangle: RegRect.         Saving rectangles in registers.
* Configurations: RegConfig.  Saving window configurations in registers.
* Files: RegFiles.            File names in registers.
* Numbers: RegNumbers.        Numbers in registers.
* Bookmarks::                 Bookmarks are like registers, but persistent.
@end menu

@node RegPos, RegText, Registers, Registers
@section Saving Positions in Registers

  Saving a position records a place in a buffer so that you can move
back there later.  Moving to a saved position switches to that buffer
and moves point to that place in it.

@table @kbd
@item C-x r @key{SPC} @var{r}
Save position of point in register @var{r} (@code{point-to-register}).
@item C-x r j @var{r}
Jump to the position saved in register @var{r} (@code{jump-to-register}).
@end table

@kindex C-x r SPC
@findex point-to-register
  To save the current position of point in a register, choose a name
@var{r} and type @kbd{C-x r @key{SPC} @var{r}}.  The register @var{r}
retains the position thus saved until you store something else in that
register.

@kindex C-x r j
@findex jump-to-register
  The command @kbd{C-x r j @var{r}} moves point to the position recorded
in register @var{r}.  The register is not affected; it continues to
record the same location.  You can jump to the same position using the
same register as often as you want.

  If you use @kbd{C-x r j} to go to a saved position, but the buffer it
was saved from has been killed, @kbd{C-x r j} tries to create the buffer
again by visiting the same file.  Of course, this works only for buffers
that were visiting files.

@node RegText, RegRect, RegPos, Registers
@section Saving Text in Registers

  When you want to insert a copy of the same piece of text many times, it
can be impractical to use the kill ring, since each subsequent kill moves
the piece of text further down on the ring.  It becomes hard to keep
track of the argument needed to retrieve the same text with @kbd{C-y}.  An
alternative is to store the text in a register with @kbd{C-x r s}
(@code{copy-to-register}) and then retrieve it with @kbd{C-x r i}
(@code{insert-register}).

@table @kbd
@item C-x r s @var{r}
Copy region into register @var{r} (@code{copy-to-register}).
@item C-x r g @var{r}
@itemx C-x r i @var{r}
Insert text contents of register @var{r} (@code{insert-register}).
@end table

@kindex C-x r s
@kindex C-x r g
@kindex C-x r i
@findex copy-to-register
@findex insert-register
  @kbd{C-x r s @var{r}} stores a copy of the text of the region into the
register named @var{r}.  Given a numeric argument, @kbd{C-x r s @var{r}}
deletes the text from the buffer as well.

  @kbd{C-x r i @var{r}} inserts the text from register @var{r} in the buffer.
By default it leaves point before the text and places the mark after
it. With a numeric argument (@kbd{C-u}), it puts point after the text
and the mark before it.

@node RegRect, RegConfig, RegText, Registers
@section Saving Rectangles in Registers
@cindex rectangle

  A register can contain a rectangle instead of lines of text.  The rectangle
is represented as a list of strings.  @xref{Rectangles}, for basic
information on rectangles and how to specify rectangles in a buffer.

@table @kbd
@findex copy-rectangle-to-register
@kindex C-x r r
@item C-x r r @var{r}
Copy the region-rectangle into register @var{r}
(@code{copy-rectangle-to-register}).  With a numeric argument, delete it
as well.
@item C-x r g @var{r}
@itemx C-x r i @var{r}
Insert the rectangle stored in register @var{r} (if it contains a
rectangle) (@code{insert-register}).
@end table

  The @kbd{C-x r i @var{r}} command inserts linear text if the register
  contains
that, or inserts a rectangle if the register contains one.

  See also the command @code{sort-columns}, which you can think of
as sorting a rectangle.  @xref{Sorting}.

@node RegConfig, RegNumbers, RegRect, Registers
@section Saving Window Configurations in Registers

@findex window-configuration-to-register
@findex frame-configuration-to-register
@kindex C-x r w
@c @kindex C-x r f
  You can save the window configuration of the selected frame in a
register, or even the configuration of all windows in all frames, and
restore the configuration later.

@table @kbd
@item C-x r w @var{r}
Save the state of the selected frame's windows in register @var{r}
(@code{window-configuration-to-register}).
@c @item C-x r f @var{r}
@item M-x frame-configuration-to-register @key{RET} @var{r}
Save the state of all frames, including all their windows, in register
@var{r} (@code{frame-configuration-to-register}).
@end table

  Use @kbd{C-x r j @var{r}} to restore a window or frame configuration.
This is the same command used to restore a cursor position.  When you
restore a frame configuration, any existing frames not included in the
configuration become invisible.  If you wish to delete these frames
instead, use @kbd{C-u C-x r j @var{r}}.

@node RegNumbers, RegFiles, RegConfig, Registers
@section Keeping Numbers in Registers

  There are commands to store a number in a register, to insert
the number in the buffer in decimal, and to increment it.  These commands
can be useful in keyboard macros (@pxref{Keyboard Macros}).

@table @kbd
@item C-u @var{number} C-x r n @var{reg}
@kindex C-x r n
@findex number-to-register
Store @var{number} into register @var{reg} (@code{number-to-register}).
@item C-u @var{number} C-x r + @var{reg}
@kindex C-x r +
@findex increment-register
Increment the number in register @var{reg} by @var{number}
(@code{increment-register}).
@item C-x r g @var{reg}
Insert the number from register @var{reg} into the buffer.
@end table

  @kbd{C-x r g} is the same command used to insert any other
sort of register contents into the buffer.

@node RegFiles, Bookmarks, RegNumbers, Registers
@section Keeping File Names in Registers

  If you visit certain file names frequently, you can visit them more
conveniently if you put their names in registers.  Here's the Lisp code
used to put a file name in a register:

@smallexample
(set-register ?@var{r} '(file . @var{name}))
@end smallexample

@need 3000
@noindent
For example,

@smallexample
(set-register ?z '(file . "/usr/src/xemacs/src/ChangeLog"))
@end smallexample

@noindent
puts the file name shown in register @samp{z}.

  To visit the file whose name is in register @var{r}, type @kbd{C-x r j
@var{r}}.  (This is the same command used to jump to a position or
restore a frame configuration.)

@node Bookmarks,  , RegFiles, Registers
@section Bookmarks
@cindex bookmarks

  @dfn{Bookmarks} are somewhat like registers in that they record
positions you can jump to.  Unlike registers, they have long names, and
they persist automatically from one Emacs session to the next.  The
prototypical use of bookmarks is to record ``where you were reading'' in
various files.

  Note: bookmark.el is distributed in edit-utils package.  You need to
install that to use bookmark facility (@pxref{Packages}).

@table @kbd
@item C-x r m @key{RET}
Set the bookmark for the visited file, at point.

@item C-x r m @var{bookmark} @key{RET}
@findex bookmark-set
Set the bookmark named @var{bookmark} at point (@code{bookmark-set}).

@item C-x r b @var{bookmark} @key{RET}
@findex bookmark-jump
Jump to the bookmark named @var{bookmark} (@code{bookmark-jump}).

@item C-x r l
@findex list-bookmarks
List all bookmarks (@code{list-bookmarks}).

@item M-x bookmark-save
@findex bookmark-save
Save all the current bookmark values in the default bookmark file.
@end table

@kindex C-x r m
@findex bookmark-set
@kindex C-x r b
@findex bookmark-jump
  The prototypical use for bookmarks is to record one current position
in each of several files.  So the command @kbd{C-x r m}, which sets a
bookmark, uses the visited file name as the default for the bookmark
name.  If you name each bookmark after the file it points to, then you
can conveniently revisit any of those files with @kbd{C-x r b}, and move
to the position of the bookmark at the same time.

@kindex C-x r l
  To display a list of all your bookmarks in a separate buffer, type
@kbd{C-x r l} (@code{list-bookmarks}).  If you switch to that buffer,
you can use it to edit your bookmark definitions or annotate the
bookmarks.  Type @kbd{C-h m} in that buffer for more information about
its special editing commands.

  When you kill XEmacs, XEmacs offers to save your bookmark values in
your default bookmark file, @file{~/.emacs.bmk}, if you have changed any
bookmark values.  You can also save the bookmarks at any time with the
@kbd{M-x bookmark-save} command.  The bookmark commands load your
default bookmark file automatically.  This saving and loading is how
bookmarks persist from one XEmacs session to the next.

@vindex bookmark-save-flag
  If you set the variable @code{bookmark-save-flag} to 1, then each
command that sets a bookmark will also save your bookmarks; this way,
you don't lose any bookmark values even if XEmacs crashes.  (The value,
if a number, says how many bookmark modifications should go by between
saving.)

@vindex bookmark-search-size
  Bookmark position values are saved with surrounding context, so that
@code{bookmark-jump} can find the proper position even if the file is
modified slightly.  The variable @code{bookmark-search-size} says how
many characters of context to record, on each side of the bookmark's
position.

  Here are some additional commands for working with bookmarks:

@table @kbd
@item M-x bookmark-load @key{RET} @var{filename} @key{RET}
@findex bookmark-load
Load a file named @var{filename} that contains a list of bookmark
values.  You can use this command, as well as @code{bookmark-write}, to
work with other files of bookmark values in addition to your default
bookmark file.

@item M-x bookmark-write @key{RET} @var{filename} @key{RET}
@findex bookmark-write
Save all the current bookmark values in the file @var{filename}.

@item M-x bookmark-delete @key{RET} @var{bookmark} @key{RET}
@findex bookmark-delete
Delete the bookmark named @var{bookmark}.

@item M-x bookmark-insert-location @key{RET} @var{bookmark} @key{RET}
@findex bookmark-insert-location
Insert in the buffer the name of the file that bookmark @var{bookmark}
points to.

@item M-x bookmark-insert @key{RET} @var{bookmark} @key{RET}
@findex bookmark-insert
Insert in the buffer the @emph{contents} of the file that bookmark
@var{bookmark} points to.
@end table