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This is Info file elisp, produced by Makeinfo-1.63 from the input file elisp.texi. This version is the edition 2.4.2 of the GNU Emacs Lisp Reference Manual. It corresponds to Emacs Version 19.34. Published by the Free Software Foundation 59 Temple Place, Suite 330 Boston, MA 02111-1307 USA Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1996 Free Software Foundation, Inc. Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Permission is granted to copy and distribute translations of this manual into another language, under the above conditions for modified versions, except that this permission notice may be stated in a translation approved by the Foundation. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided also that the section entitled "GNU General Public License" is included exactly as in the original, and provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Permission is granted to copy and distribute translations of this manual into another language, under the above conditions for modified versions, except that the section entitled "GNU General Public License" may be included in a translation approved by the Free Software Foundation instead of in the original English. File: elisp, Node: Temporary Displays, Next: Overlays, Prev: Overlay Arrow, Up: Display Temporary Displays ================== Temporary displays are used by commands to put output into a buffer and then present it to the user for perusal rather than for editing. Many of the help commands use this feature. - Special Form: with-output-to-temp-buffer BUFFER-NAME FORMS... This function executes FORMS while arranging to insert any output they print into the buffer named BUFFER-NAME. The buffer is then shown in some window for viewing, displayed but not selected. The string BUFFER-NAME specifies the temporary buffer, which need not already exist. The argument must be a string, not a buffer. The buffer is erased initially (with no questions asked), and it is marked as unmodified after `with-output-to-temp-buffer' exits. `with-output-to-temp-buffer' binds `standard-output' to the temporary buffer, then it evaluates the forms in FORMS. Output using the Lisp output functions within FORMS goes by default to that buffer (but screen display and messages in the echo area, although they are "output" in the general sense of the word, are not affected). *Note Output Functions::. The value of the last form in FORMS is returned. ---------- Buffer: foo ---------- This is the contents of foo. ---------- Buffer: foo ---------- (with-output-to-temp-buffer "foo" (print 20) (print standard-output)) => #<buffer foo> ---------- Buffer: foo ---------- 20 #<buffer foo> ---------- Buffer: foo ---------- - Variable: temp-buffer-show-function If this variable is non-`nil', `with-output-to-temp-buffer' calls it as a function to do the job of displaying a help buffer. The function gets one argument, which is the buffer it should display. In Emacs versions 18 and earlier, this variable was called `temp-buffer-show-hook'. - Function: momentary-string-display STRING POSITION &optional CHAR MESSAGE This function momentarily displays STRING in the current buffer at POSITION. It has no effect on the undo list or on the buffer's modification status. The momentary display remains until the next input event. If the next input event is CHAR, `momentary-string-display' ignores it and returns. Otherwise, that event remains buffered for subsequent use as input. Thus, typing CHAR will simply remove the string from the display, while typing (say) `C-f' will remove the string from the display and later (presumably) move point forward. The argument CHAR is a space by default. The return value of `momentary-string-display' is not meaningful. If the string STRING does not contain control characters, you can do the same job in a more general way by creating an overlay with a `before-string' property. *Note Overlay Properties::. If MESSAGE is non-`nil', it is displayed in the echo area while STRING is displayed in the buffer. If it is `nil', a default message says to type CHAR to continue. In this example, point is initially located at the beginning of the second line: ---------- Buffer: foo ---------- This is the contents of foo. -!-Second line. ---------- Buffer: foo ---------- (momentary-string-display "**** Important Message! ****" (point) ?\r "Type RET when done reading") => t ---------- Buffer: foo ---------- This is the contents of foo. **** Important Message! ****Second line. ---------- Buffer: foo ---------- ---------- Echo Area ---------- Type RET when done reading ---------- Echo Area ---------- File: elisp, Node: Overlays, Next: Faces, Prev: Temporary Displays, Up: Display Overlays ======== You can use "overlays" to alter the appearance of a buffer's text on the screen, for the sake of presentation features. An overlay is an object that belongs to a particular buffer, and has a specified beginning and end. It also has properties that you can examine and set; these affect the display of the text within the overlay. * Menu: * Overlay Properties:: How to read and set properties. What properties do to the screen display. * Managing Overlays:: Creating, moving, finding overlays. File: elisp, Node: Overlay Properties, Next: Managing Overlays, Up: Overlays Overlay Properties ------------------ Overlay properties are like text properties in some respects, but the differences are more important than the similarities. Text properties are considered a part of the text; overlays are specifically considered not to be part of the text. Thus, copying text between various buffers and strings preserves text properties, but does not try to preserve overlays. Changing a buffer's text properties marks the buffer as modified, while moving an overlay or changing its properties does not. Unlike text propery changes, overlay changes are not recorded in the buffer's undo list. `priority' This property's value (which should be a nonnegative number) determines the priority of the overlay. The priority matters when two or more overlays cover the same character and both specify a face for display; the one whose `priority' value is larger takes priority over the other, and its face attributes override the face attributes of the lower priority overlay. Currently, all overlays take priority over text properties. Please avoid using negative priority values, as we have not yet decided just what they should mean. `window' If the `window' property is non-`nil', then the overlay applies only on that window. `category' If an overlay has a `category' property, we call it the "category" of the overlay. It should be a symbol. The properties of the symbol serve as defaults for the properties of the overlay. `face' This property controls the font and color of text. Its value is a face name or a list of face names. *Note Faces::, for more information. This feature may be temporary; in the future, we may replace it with other ways of specifying how to display text. `mouse-face' This property is used instead of `face' when the mouse is within the range of the overlay. This feature may be temporary, like `face'. `modification-hooks' This property's value is a list of functions to be called if any character within the overlay is changed or if text is inserted strictly within the overlay. The hook functions are called both before and after each change. If the functions save the information they receive, and compare notes between calls, they can determine exactly what change has been made in the buffer text. When called before a change, each function receives four arguments: the overlay, `nil', and the beginning and end of the text range to be modified. When called after a change, each function receives five arguments: the overlay, `t', the beginning and end of the text range just modified, and the length of the pre-change text replaced by that range. (For an insertion, the pre-change length is zero; for a deletion, that length is the number of characters deleted, and the post-change beginning and end are equal.) `insert-in-front-hooks' This property's value is a list of functions to be called before and after inserting text right at the beginning of the overlay. The calling conventions are the same as for the `modification-hooks' functions. `insert-behind-hooks' This property's value is a list of functions to be called before and after inserting text right at the end of the overlay. The calling conventions are the same as for the `modification-hooks' functions. `invisible' The `invisible' property can make the text in the overlay invisible, which means that it does not appear on the screen. *Note Invisible Text::, for details. `before-string' This property's value is a string to add to the display at the beginning of the overlay. The string does not appear in the buffer in any sense--only on the screen. The string should contain only characters that display as a single column--control characters, including tabs or newlines, will give strange results. `after-string' This property's value is a string to add to the display at the end of the overlay. The string does not appear in the buffer in any sense--only on the screen. The string should contain only characters that display as a single column--control characters, including tabs or newlines, will give strange results. `evaporate' If this property is non-`nil', the overlay is deleted automatically if it ever becomes empty (i.e., if it spans no characters). `local-map' If this property is non-`nil', it specifies a keymap for a portion of the text. The property's value replaces the buffer's local map, when the character after point is within the overlay. *Note Active Keymaps::. These are the functions for reading and writing the properties of an overlay. - Function: overlay-get OVERLAY PROP This function returns the value of property PROP recorded in OVERLAY, if any. If OVERLAY does not record any value for that property, but it does have a `category' property which is a symbol, that symbol's PROP property is used. Otherwise, the value is `nil'. - Function: overlay-put OVERLAY PROP VALUE This function sets the value of property PROP recorded in OVERLAY to VALUE. It returns VALUE. See also the function `get-char-property' which checks both overlay properties and text properties for a given character. *Note Examining Properties::. File: elisp, Node: Managing Overlays, Prev: Overlay Properties, Up: Overlays Managing Overlays ----------------- This section describes the functions to create, delete and move overlays, and to examine their contents. - Function: make-overlay START END &optional BUFFER This function creates and returns an overlay that belongs to BUFFER and ranges from START to END. Both START and END must specify buffer positions; they may be integers or markers. If BUFFER is omitted, the overlay is created in the current buffer. - Function: overlay-start OVERLAY This function returns the position at which OVERLAY starts. - Function: overlay-end OVERLAY This function returns the position at which OVERLAY ends. - Function: overlay-buffer OVERLAY This function returns the buffer that OVERLAY belongs to. - Function: delete-overlay OVERLAY This function deletes OVERLAY. The overlay continues to exist as a Lisp object, but ceases to be part of the buffer it belonged to, and ceases to have any effect on display. - Function: move-overlay OVERLAY START END &optional BUFFER This function moves OVERLAY to BUFFER, and places its bounds at START and END. Both arguments START and END must specify buffer positions; they may be integers or markers. If BUFFER is omitted, the overlay stays in the same buffer. The return value is OVERLAY. This is the only valid way to change the endpoints of an overlay. Do not try modifying the markers in the overlay by hand, as that fails to update other vital data structures and can cause some overlays to be "lost". - Function: overlays-at POS This function returns a list of all the overlays that contain position POS in the current buffer. The list is in no particular order. An overlay contains position POS if it begins at or before POS, and ends after POS. - Function: next-overlay-change POS This function returns the buffer position of the next beginning or end of an overlay, after POS. - Function: previous-overlay-change POS This function returns the buffer position of the previous beginning or end of an overlay, before POS. File: elisp, Node: Faces, Next: Blinking, Prev: Overlays, Up: Display Faces ===== A "face" is a named collection of graphical attributes: font, foreground color, background color and optional underlining. Faces control the display of text on the screen. Each face has its own "face id number" which distinguishes faces at low levels within Emacs. However, for most purposes, you can refer to faces in Lisp programs by their names. - Function: facep OBJECT This function returns `t' if OBJECT is a face name symbol (or if it is a vector of the kind used internally to record face data). It returns `nil' otherwise. Each face name is meaningful for all frames, and by default it has the same meaning in all frames. But you can arrange to give a particular face name a special meaning in one frame if you wish. * Menu: * Standard Faces:: The faces Emacs normally comes with. * Merging Faces:: How Emacs decides which face to use for a character. * Face Functions:: How to define and examine faces. File: elisp, Node: Standard Faces, Next: Merging Faces, Up: Faces Standard Faces -------------- This table lists all the standard faces and their uses. `default' This face is used for ordinary text. `modeline' This face is used for mode lines and menu bars. `region' This face is used for highlighting the region in Transient Mark mode. `secondary-selection' This face is used to show any secondary selection you have made. `highlight' This face is meant to be used for highlighting for various purposes. `underline' This face underlines text. `bold' This face uses a bold font, if possible. It uses the bold variant of the frame's font, if it has one. It's up to you to choose a default font that has a bold variant, if you want to use one. `italic' This face uses the italic variant of the frame's font, if it has one. `bold-italic' This face uses the bold italic variant of the frame's font, if it has one. File: elisp, Node: Merging Faces, Next: Face Functions, Prev: Standard Faces, Up: Faces Merging Faces for Display ------------------------- Here are all the ways to specify which face to use for display of text: * With defaults. Each frame has a "default face", whose id number is zero, which is used for all text that doesn't somehow specify another face. * With text properties. A character may have a `face' property; if so, it is displayed with that face. *Note Special Properties::. If the character has a `mouse-face' property, that is used instead of the `face' property when the mouse is "near enough" to the character. * With overlays. An overlay may have `face' and `mouse-face' properties too; they apply to all the text covered by the overlay. * With a region that is active. In Transient Mark mode, the region is highlighted with a particular face (see `region-face', below). * With special glyphs. Each glyph can specify a particular face id number. *Note Glyphs::. If these various sources together specify more than one face for a particular character, Emacs merges the attributes of the various faces specified. The attributes of the faces of special glyphs come first; then comes the face for region highlighting, if appropriate; then come attributes of faces from overlays, followed by those from text properties, and last the default face. When multiple overlays cover one character, an overlay with higher priority overrides those with lower priority. *Note Overlays::. If an attribute such as the font or a color is not specified in any of the above ways, the frame's own font or color is used. File: elisp, Node: Face Functions, Prev: Merging Faces, Up: Faces Functions for Working with Faces -------------------------------- The attributes a face can specify include the font, the foreground color, the background color, and underlining. The face can also leave these unspecified by giving the value `nil' for them. Here are the primitives for creating and changing faces. - Function: make-face NAME This function defines a new face named NAME, initially with all attributes `nil'. It does nothing if there is already a face named NAME. - Function: face-list This function returns a list of all defined face names. - Function: copy-face OLD-FACE NEW-NAME &optional FRAME NEW-FRAME This function defines the face NEW-NAME as a copy of the existing face named OLD-FACE. It creates the face NEW-NAME if that doesn't already exist. If the optional argument FRAME is given, this function applies only to that frame. Otherwise it applies to each frame individually, copying attributes from OLD-FACE in each frame to NEW-FACE in the same frame. If the optional argument NEW-FRAME is given, then `copy-face' copies the attributes of OLD-FACE in FRAME to NEW-NAME in NEW-FRAME. You can modify the attributes of an existing face with the following functions. If you specify FRAME, they affect just that frame; otherwise, they affect all frames as well as the defaults that apply to new frames. - Function: set-face-foreground FACE COLOR &optional FRAME - Function: set-face-background FACE COLOR &optional FRAME These functions set the foreground (or background, respectively) color of face FACE to COLOR. The argument COLOR should be a string, the name of a color. Certain shades of gray are implemented by stipple patterns on black-and-white screens. - Function: set-face-stipple FACE PATTERN &optional FRAME This function sets the background stipple pattern of face FACE to PATTERN. The argument PATTERN should be the name of a stipple pattern defined by the X server, or `nil' meaning don't use stipple. Normally there is no need to pay attention to stipple patterns, because they are used automatically to handle certain shades of gray. - Function: set-face-font FACE FONT &optional FRAME This function sets the font of face FACE. The argument FONT should be a string. - Function: set-face-underline-p FACE UNDERLINE-P &optional FRAME This function sets the underline attribute of face FACE. Non-`nil' means do underline; `nil' means don't. - Function: invert-face FACE &optional FRAME Swap the foreground and background colors of face FACE. If the face doesn't specify both foreground and background, then its foreground and background are set to the default background and foreground, respectively. These functions examine the attributes of a face. If you don't specify FRAME, they refer to the default data for new frames. - Function: face-foreground FACE &optional FRAME - Function: face-background FACE &optional FRAME These functions return the foreground color (or background color, respectively) of face FACE, as a string. - Function: face-stipple FACE &optional FRAME This function returns the name of the background stipple pattern of face FACE, or `nil' if it doesn't have one. - Function: face-font FACE &optional FRAME This function returns the name of the font of face FACE. - Function: face-underline-p FACE &optional FRAME This function returns the underline attribute of face FACE. - Function: face-id FACE This function returns the face id number of face FACE. - Function: face-equal FACE1 FACE2 &optional FRAME This returns `t' if the faces FACE1 and FACE2 have the same attributes for display. - Function: face-differs-from-default-p FACE &optional FRAME This returns `t' if the face FACE displays differently from the default face. A face is considered to be "the same" as the normal face if each attribute is either the same as that of the default face or `nil' (meaning to inherit from the default). - Variable: region-face This variable's value specifies the face id to use to display characters in the region when it is active (in Transient Mark mode only). The face thus specified takes precedence over all faces that come from text properties and overlays, for characters in the region. *Note The Mark::, for more information about Transient Mark mode. Normally, the value is the id number of the face named `region'. File: elisp, Node: Blinking, Next: Inverse Video, Prev: Faces, Up: Display Blinking Parentheses ==================== This section describes the mechanism by which Emacs shows a matching open parenthesis when the user inserts a close parenthesis. - Variable: blink-paren-function The value of this variable should be a function (of no arguments) to be called whenever a character with close parenthesis syntax is inserted. The value of `blink-paren-function' may be `nil', in which case nothing is done. *Please note:* This variable was named `blink-paren-hook' in older Emacs versions, but since it is not called with the standard convention for hooks, it was renamed to `blink-paren-function' in version 19. - Variable: blink-matching-paren If this variable is `nil', then `blink-matching-open' does nothing. - Variable: blink-matching-paren-distance This variable specifies the maximum distance to scan for a matching parenthesis before giving up. - Variable: blink-matching-paren-delay This variable specifies the number of seconds for the cursor to remain at the matching parenthesis. A fraction of a second often gives good results, but the default is 1, which works on all systems. - Function: blink-matching-open This function is the default value of `blink-paren-function'. It assumes that point follows a character with close parenthesis syntax and moves the cursor momentarily to the matching opening character. If that character is not already on the screen, it displays the character's context in the echo area. To avoid long delays, this function does not search farther than `blink-matching-paren-distance' characters. Here is an example of calling this function explicitly. (defun interactive-blink-matching-open () "Indicate momentarily the start of sexp before point." (interactive) (let ((blink-matching-paren-distance (buffer-size)) (blink-matching-paren t)) (blink-matching-open))) File: elisp, Node: Inverse Video, Next: Usual Display, Prev: Blinking, Up: Display Inverse Video ============= - User Option: inverse-video This variable controls whether Emacs uses inverse video for all text on the screen. Non-`nil' means yes, `nil' means no. The default is `nil'. - User Option: mode-line-inverse-video This variable controls the use of inverse video for mode lines. If it is non-`nil', then mode lines are displayed in inverse video. Otherwise, mode lines are displayed normally, just like text. The default is `t'. For X window frames, this displays mode lines using the face named `modeline', which is normally the inverse of the default face unless you change it. File: elisp, Node: Usual Display, Next: Display Tables, Prev: Inverse Video, Up: Display Usual Display Conventions ========================= The usual display conventions define how to display each character code. You can override these conventions by setting up a display table (*note Display Tables::.). Here are the usual display conventions: * Character codes 32 through 126 map to glyph codes 32 through 126. Normally this means they display as themselves. * Character code 9 is a horizontal tab. It displays as whitespace up to a position determined by `tab-width'. * Character code 10 is a newline. * All other codes in the range 0 through 31, and code 127, display in one of two ways according to the value of `ctl-arrow'. If it is non-`nil', these codes map to sequences of two glyphs, where the first glyph is the ASCII code for `^'. (A display table can specify a glyph to use instead of `^'.) Otherwise, these codes map just like the codes in the range 128 to 255. * Character codes 128 through 255 map to sequences of four glyphs, where the first glyph is the ASCII code for `\', and the others are digit characters representing the code in octal. (A display table can specify a glyph to use instead of `\'.) The usual display conventions apply even when there is a display table, for any character whose entry in the active display table is `nil'. Thus, when you set up a display table, you need only specify the characters for which you want unusual behavior. These variables affect the way certain characters are displayed on the screen. Since they change the number of columns the characters occupy, they also affect the indentation functions. - User Option: ctl-arrow This buffer-local variable controls how control characters are displayed. If it is non-`nil', they are displayed as a caret followed by the character: `^A'. If it is `nil', they are displayed as a backslash followed by three octal digits: `\001'. - Variable: default-ctl-arrow The value of this variable is the default value for `ctl-arrow' in buffers that do not override it. *Note Default Value::. - User Option: tab-width The value of this variable is the spacing between tab stops used for displaying tab characters in Emacs buffers. The default is 8. Note that this feature is completely independent from the user-settable tab stops used by the command `tab-to-tab-stop'. *Note Indent Tabs::. File: elisp, Node: Display Tables, Next: Beeping, Prev: Usual Display, Up: Display Display Tables ============== You can use the "display table" feature to control how all 256 possible character codes display on the screen. This is useful for displaying European languages that have letters not in the ASCII character set. The display table maps each character code into a sequence of "glyphs", each glyph being an image that takes up one character position on the screen. You can also define how to display each glyph on your terminal, using the "glyph table". * Menu: * Display Table Format:: What a display table consists of. * Active Display Table:: How Emacs selects a display table to use. * Glyphs:: How to define a glyph, and what glyphs mean. * ISO Latin 1:: How to use display tables to support the ISO Latin 1 character set. File: elisp, Node: Display Table Format, Next: Active Display Table, Up: Display Tables Display Table Format -------------------- A display table is actually an array of 262 elements. - Function: make-display-table This creates and returns a display table. The table initially has `nil' in all elements. The first 256 elements correspond to character codes; the Nth element says how to display the character code N. The value should be `nil' or a vector of glyph values (*note Glyphs::.). If an element is `nil', it says to display that character according to the usual display conventions (*note Usual Display::.). If you use the display table to change the display of newline characters, the whole buffer will be displayed as one long "line." The remaining six elements of a display table serve special purposes, and `nil' means use the default stated below. The glyph for the end of a truncated screen line (the default for this is `$'). *Note Glyphs::. The glyph for the end of a continued line (the default is `\'). The glyph for indicating a character displayed as an octal character code (the default is `\'). The glyph for indicating a control character (the default is `^'). A vector of glyphs for indicating the presence of invisible lines (the default is `...'). *Note Selective Display::. The glyph used to draw the border between side-by-side windows (the default is `|'). *Note Splitting Windows::. For example, here is how to construct a display table that mimics the effect of setting `ctl-arrow' to a non-`nil' value: (setq disptab (make-display-table)) (let ((i 0)) (while (< i 32) (or (= i ?\t) (= i ?\n) (aset disptab i (vector ?^ (+ i 64)))) (setq i (1+ i))) (aset disptab 127 (vector ?^ ??))) File: elisp, Node: Active Display Table, Next: Glyphs, Prev: Display Table Format, Up: Display Tables Active Display Table -------------------- Each window can specify a display table, and so can each buffer. When a buffer B is displayed in window W, display uses the display table for window W if it has one; otherwise, the display table for buffer B if it has one; otherwise, the standard display table if any. The display table chosen is called the "active" display table. - Function: window-display-table WINDOW This function returns WINDOW's display table, or `nil' if WINDOW does not have an assigned display table. - Function: set-window-display-table WINDOW TABLE This function sets the display table of WINDOW to TABLE. The argument TABLE should be either a display table or `nil'. - Variable: buffer-display-table This variable is automatically local in all buffers; its value in a particular buffer is the display table for that buffer, or `nil' if the buffer does not have an assigned display table. - Variable: standard-display-table This variable's value is the default display table, used whenever a window has no display table and neither does the buffer displayed in that window. This variable is `nil' by default. If there is no display table to use for a particular window--that is, if the window has none, its buffer has none, and `standard-display-table' has none--then Emacs uses the usual display conventions for all character codes in that window. *Note Usual Display::. File: elisp, Node: Glyphs, Next: ISO Latin 1, Prev: Active Display Table, Up: Display Tables Glyphs ------ A "glyph" is a generalization of a character; it stands for an image that takes up a single character position on the screen. Glyphs are represented in Lisp as integers, just as characters are. The meaning of each integer, as a glyph, is defined by the glyph table, which is the value of the variable `glyph-table'. - Variable: glyph-table The value of this variable is the current glyph table. It should be a vector; the Gth element defines glyph code G. If the value is `nil' instead of a vector, then all glyphs are simple (see below). Here are the possible types of elements in the glyph table: STRING Send the characters in STRING to the terminal to output this glyph. This alternative is available on character terminals, but not under X. INTEGER Define this glyph code as an alias for code INTEGER. You can use an alias to specify a face code for the glyph; see below. `NIL' This glyph is simple. On an ordinary terminal, the glyph code mod 256 is the character to output. With X, the glyph code mod 256 is the character to output, and the glyph code divided by 256 specifies the "face id number" to use while outputting it. *Note Faces::. If a glyph code is greater than or equal to the length of the glyph table, that code is automatically simple. File: elisp, Node: ISO Latin 1, Prev: Glyphs, Up: Display Tables ISO Latin 1 ----------- If you have a terminal that can handle the entire ISO Latin 1 character set, you can arrange to use that character set as follows: (require 'disp-table) ;; Set char codes 160--255 to display as themselves. ;; (Codes 128--159 are the additional control characters.) (standard-display-8bit 160 255) If you are editing buffers written in the ISO Latin 1 character set and your terminal doesn't handle anything but ASCII, you can load the file `iso-ascii' to set up a display table that displays the other ISO characters as explanatory sequences of ASCII characters. For example, the character "o with umlaut" displays as `{"o}'. Some European countries have terminals that don't support ISO Latin 1 but do support the special characters for that country's language. You can define a display table to work one language using such terminals. For an example, see `lisp/iso-swed.el', which handles certain Swedish terminals. You can load the appropriate display table for your terminal automatically by writing a terminal-specific Lisp file for the terminal type. File: elisp, Node: Beeping, Next: Window Systems, Prev: Display Tables, Up: Display Beeping ======= You can make Emacs ring a bell (or blink the screen) to attract the user's attention. Be conservative about how often you do this; frequent bells can become irritating. Also be careful not to use beeping alone when signaling an error is appropriate. (*Note Errors::.) - Function: ding &optional DONT-TERMINATE This function beeps, or flashes the screen (see `visible-bell' below). It also terminates any keyboard macro currently executing unless DONT-TERMINATE is non-`nil'. - Function: beep &optional DONT-TERMINATE This is a synonym for `ding'. - Variable: visible-bell This variable determines whether Emacs should flash the screen to represent a bell. Non-`nil' means yes, `nil' means no. This is effective under X windows, and on a character-only terminal provided the terminal's Termcap entry defines the visible bell capability (`vb'). File: elisp, Node: Window Systems, Prev: Beeping, Up: Display Window Systems ============== Emacs works with several window systems, most notably the X Window System. Both Emacs and X use the term "window", but use it differently. An Emacs frame is a single window as far as X is concerned; the individual Emacs windows are not known to X at all. - Variable: window-system This variable tells Lisp programs what window system Emacs is running under. Its value should be a symbol such as `x' (if Emacs is running under X) or `nil' (if Emacs is running on an ordinary terminal). - Variable: window-setup-hook This variable is a normal hook which Emacs runs after loading your `.emacs' file and the default initialization file (if any), after loading terminal-specific Lisp code, and after running the hook `term-setup-hook'. This hook is used for internal purposes: setting up communication with the window system, and creating the initial window. Users should not interfere with it. File: elisp, Node: Calendar, Next: Tips, Prev: Display, Up: Top Customizing the Calendar and Diary ********************************** There are many customizations that you can use to make the calendar and diary suit your personal tastes. * Menu: * Calendar Customizing:: Defaults you can set. * Holiday Customizing:: Defining your own holidays. * Date Display Format:: Changing the format. * Time Display Format:: Changing the format. * Daylight Savings:: Changing the default. * Diary Customizing:: Defaults you can set. * Hebrew/Islamic Entries:: How to obtain them. * Fancy Diary Display:: Enhancing the diary display, sorting entries, using included diary files. * Sexp Diary Entries:: Fancy things you can do. * Appt Customizing:: Customizing appointment reminders. File: elisp, Node: Calendar Customizing, Next: Holiday Customizing, Up: Calendar Customizing the Calendar ======================== If you set the variable `view-diary-entries-initially' to `t', calling up the calendar automatically displays the diary entries for the current date as well. The diary dates appear only if the current date is visible. If you add both of the following lines to your `.emacs' file: (setq view-diary-entries-initially t) (calendar) this displays both the calendar and diary windows whenever you start Emacs. Similarly, if you set the variable `view-calendar-holidays-initially' to `t', entering the calendar automatically displays a list of holidays for the current three-month period. The holiday list appears in a separate window. You can set the variable `mark-diary-entries-in-calendar' to `t' in order to mark any dates with diary entries. This takes effect whenever the calendar window contents are recomputed. There are two ways of marking these dates: by changing the face (*note Faces::.), if the display supports that, or by placing a plus sign (`+') beside the date otherwise. Similarly, setting the variable `mark-holidays-in-calendar' to `t' marks holiday dates, either with a change of face or with an asterisk (`*'). The variable `calendar-holiday-marker' specifies how to mark a date as being a holiday. Its value may be a character to insert next to the date, or a face name to use for displaying the date. Likewise, the variable `diary-entry-marker' specifies how to mark a date that has diary entries. The calendar creates faces named `holiday-face' and `diary-face' for these purposes; those symbols are the default values of these variables, when Emacs supports multiple faces on your terminal. The variable `calendar-load-hook' is a normal hook run when the calendar package is first loaded (before actually starting to display the calendar). Starting the calendar runs the normal hook `initial-calendar-window-hook'. Recomputation of the calendar display does not run this hook. But if you leave the calendar with the `q' command and reenter it, the hook runs again. The variable `today-visible-calendar-hook' is a normal hook run after the calendar buffer has been prepared with the calendar when the current date is visible in the window. One use of this hook is to replace today's date with asterisks; to do that, use the hook function `calendar-star-date'. (add-hook 'today-visible-calendar-hook 'calendar-star-date) Another standard hook function marks the current date, either by changing its face or by adding an asterisk. Here's how to use it: (add-hook 'today-visible-calendar-hook 'calendar-mark-today) The variable `calendar-today-marker' specifies how to mark today's date. Its value should be a character to insert next to the date or a face name to use for displaying the date. A face named `calendar-today-face' is provided for this purpose; that symbol is the default for this variable when Emacs supports multiple faces on your terminal. A similar normal hook, `today-invisible-calendar-hook' is run if the current date is *not* visible in the window. File: elisp, Node: Holiday Customizing, Next: Date Display Format, Prev: Calendar Customizing, Up: Calendar Customizing the Holidays ======================== Emacs knows about holidays defined by entries on one of several lists. You can customize these lists of holidays to your own needs, adding or deleting holidays. The lists of holidays that Emacs uses are for general holidays (`general-holidays'), local holidays (`local-holidays'), Christian holidays (`christian-holidays'), Hebrew (Jewish) holidays (`hebrew-holidays'), Islamic (Moslem) holidays (`islamic-holidays'), and other holidays (`other-holidays'). The general holidays are, by default, holidays common throughout the United States. To eliminate these holidays, set `general-holidays' to `nil'. There are no default local holidays (but sites may supply some). You can set the variable `local-holidays' to any list of holidays, as described below. By default, Emacs does not include all the holidays of the religions that it knows, only those commonly found in secular calendars. For a more extensive collection of religious holidays, you can set any (or all) of the variables `all-christian-calendar-holidays', `all-hebrew-calendar-holidays', or `all-islamic-calendar-holidays' to `t'. If you want to eliminate the religious holidays, set any or all of the corresponding variables `christian-holidays', `hebrew-holidays', and `islamic-holidays' to `nil'. You can set the variable `other-holidays' to any list of holidays. This list, normally empty, is intended for individual use. Each of the lists (`general-holidays', `local-holidays', `christian-holidays', `hebrew-holidays', `islamic-holidays', and `other-holidays') is a list of "holiday forms", each holiday form describing a holiday (or sometimes a list of holidays). Here is a table of the possible kinds of holiday form. Day numbers and month numbers count starting from 1, but "dayname" numbers count Sunday as 0. The element STRING is always the name of the holiday, as a string. `(holiday-fixed MONTH DAY STRING)' A fixed date on the Gregorian calendar. `(holiday-float MONTH DAYNAME K STRING)' The Kth DAYNAME in MONTH on the Gregorian calendar (DAYNAME=0 for Sunday, and so on); negative K means count back from the end of the month. `(holiday-hebrew MONTH DAY STRING)' A fixed date on the Hebrew calendar. `(holiday-islamic MONTH DAY STRING)' A fixed date on the Islamic calendar. `(holiday-julian MONTH DAY STRING)' A fixed date on the Julian calendar. `(holiday-sexp SEXP STRING)' A date calculated by the Lisp expression SEXP. The expression should use the variable `year' to compute and return the date of a holiday, or `nil' if the holiday doesn't happen this year. The value of SEXP must represent the date as a list of the form `(MONTH DAY YEAR)'. `(if CONDITION HOLIDAY-FORM)' A holiday that happens only if CONDITION is true. `(FUNCTION [ARGS])' A list of dates calculated by the function FUNCTION, called with arguments ARGS. For example, suppose you want to add Bastille Day, celebrated in France on July 14. You can do this as follows: (setq other-holidays '((holiday-fixed 7 14 "Bastille Day"))) The holiday form `(holiday-fixed 7 14 "Bastille Day")' specifies the fourteenth day of the seventh month (July). Many holidays occur on a specific day of the week, at a specific time of month. Here is a holiday form describing Hurricane Supplication Day, celebrated in the Virgin Islands on the fourth Monday in August: (holiday-float 8 1 4 "Hurricane Supplication Day") Here the 8 specifies August, the 1 specifies Monday (Sunday is 0, Tuesday is 2, and so on), and the 4 specifies the fourth occurrence in the month (1 specifies the first occurrence, 2 the second occurrence, -1 the last occurrence, -2 the second-to-last occurrence, and so on). You can specify holidays that occur on fixed days of the Hebrew, Islamic, and Julian calendars too. For example, (setq other-holidays '((holiday-hebrew 10 2 "Last day of Hanukkah") (holiday-islamic 3 12 "Mohammed's Birthday") (holiday-julian 4 2 "Jefferson's Birthday"))) adds the last day of Hanukkah (since the Hebrew months are numbered with 1 starting from Nisan), the Islamic feast celebrating Mohammed's birthday (since the Islamic months are numbered from 1 starting with Muharram), and Thomas Jefferson's birthday, which is 2 April 1743 on the Julian calendar. To include a holiday conditionally, use either Emacs Lisp's `if' or the `holiday-sexp' form. For example, American presidential elections occur on the first Tuesday after the first Monday in November of years divisible by 4: (holiday-sexp (if (= 0 (% year 4)) (calendar-gregorian-from-absolute (1+ (calendar-dayname-on-or-before 1 (+ 6 (calendar-absolute-from-gregorian (list 11 1 year)))))) "US Presidential Election")) (if (= 0 (% displayed-year 4)) (fixed 11 (extract-calendar-day (calendar-gregorian-from-absolute (1+ (calendar-dayname-on-or-before 1 (+ 6 (calendar-absolute-from-gregorian (list 11 1 displayed-year))))))) "US Presidential Election")) Some holidays just don't fit into any of these forms because special calculations are involved in their determination. In such cases you must write a Lisp function to do the calculation. To include eclipses, for example, add `(eclipses)' to `other-holidays' and write an Emacs Lisp function `eclipses' that returns a (possibly empty) list of the relevant Gregorian dates among the range visible in the calendar window, with descriptive strings, like this: (((6 27 1991) "Lunar Eclipse") ((7 11 1991) "Solar Eclipse") ... ) File: elisp, Node: Date Display Format, Next: Time Display Format, Prev: Holiday Customizing, Up: Calendar Date Display Format =================== You can customize the manner of displaying dates in the diary, in mode lines, and in messages by setting `calendar-date-display-form'. This variable holds a list of expressions that can involve the variables `month', `day', and `year', which are all numbers in string form, and `monthname' and `dayname', which are both alphabetic strings. In the American style, the default value of this list is as follows: ((if dayname (concat dayname ", ")) monthname " " day ", " year) while in the European style this value is the default: ((if dayname (concat dayname ", ")) day " " monthname " " year) The ISO standard date representation is this: (year "-" month "-" day) This specifies a typical American format: (month "/" day "/" (substring year -2)) File: elisp, Node: Time Display Format, Next: Daylight Savings, Prev: Date Display Format, Up: Calendar Time Display Format =================== The calendar and diary by default display times of day in the conventional American style with the hours from 1 through 12, minutes, and either `am' or `pm'. If you prefer the European style, also known in the US as military, in which the hours go from 00 to 23, you can alter the variable `calendar-time-display-form'. This variable is a list of expressions that can involve the variables `12-hours', `24-hours', and `minutes', which are all numbers in string form, and `am-pm' and `time-zone', which are both alphabetic strings. The default value of `calendar-time-display-form' is as follows: (12-hours ":" minutes am-pm (if time-zone " (") time-zone (if time-zone ")")) Here is a value that provides European style times: (24-hours ":" minutes (if time-zone " (") time-zone (if time-zone ")"))