Foundation instead of in the original English.
\1f
+File: lispref.info, Node: Buffer Contents, Next: Comparing Text, Prev: Near Point, Up: Text
+
+Examining Buffer Contents
+=========================
+
+ This section describes two functions that allow a Lisp program to
+convert any portion of the text in the buffer into a string.
+
+ - Function: buffer-substring start end &optional buffer
+ - Function: buffer-string start end &optional buffer
+ These functions are equivalent and return a string containing a
+ copy of the text of the region defined by positions START and END
+ in the buffer. If the arguments are not positions in the
+ accessible portion of the buffer, `buffer-substring' signals an
+ `args-out-of-range' error. If optional argument BUFFER is `nil',
+ the current buffer is assumed.
+
+ If the region delineated by START and END contains duplicable
+ extents, they will be remembered in the string. *Note Duplicable
+ Extents::.
+
+ It is not necessary for START to be less than END; the arguments
+ can be given in either order. But most often the smaller argument
+ is written first.
+
+ ---------- Buffer: foo ----------
+ This is the contents of buffer foo
+
+ ---------- Buffer: foo ----------
+
+ (buffer-substring 1 10)
+ => "This is t"
+ (buffer-substring (point-max) 10)
+ => "he contents of buffer foo
+ "
+
+\1f
+File: lispref.info, Node: Comparing Text, Next: Insertion, Prev: Buffer Contents, Up: Text
+
+Comparing Text
+==============
+
+ This function lets you compare portions of the text in a buffer,
+without copying them into strings first.
+
+ - Function: compare-buffer-substrings buffer1 start1 end1 buffer2
+ start2 end2
+ This function lets you compare two substrings of the same buffer
+ or two different buffers. The first three arguments specify one
+ substring, giving a buffer and two positions within the buffer.
+ The last three arguments specify the other substring in the same
+ way. You can use `nil' for BUFFER1, BUFFER2, or both to stand for
+ the current buffer.
+
+ The value is negative if the first substring is less, positive if
+ the first is greater, and zero if they are equal. The absolute
+ value of the result is one plus the index of the first differing
+ characters within the substrings.
+
+ This function ignores case when comparing characters if
+ `case-fold-search' is non-`nil'. It always ignores text
+ properties.
+
+ Suppose the current buffer contains the text `foobarbar
+ haha!rara!'; then in this example the two substrings are `rbar '
+ and `rara!'. The value is 2 because the first substring is greater
+ at the second character.
+
+ (compare-buffer-substring nil 6 11 nil 16 21)
+ => 2
+
+\1f
+File: lispref.info, Node: Insertion, Next: Commands for Insertion, Prev: Comparing Text, Up: Text
+
+Inserting Text
+==============
+
+ "Insertion" means adding new text to a buffer. The inserted text
+goes at point--between the character before point and the character
+after point.
+
+ Insertion relocates markers that point at positions after the
+insertion point, so that they stay with the surrounding text (*note
+Markers::). When a marker points at the place of insertion, insertion
+normally doesn't relocate the marker, so that it points to the
+beginning of the inserted text; however, certain special functions such
+as `insert-before-markers' relocate such markers to point after the
+inserted text.
+
+ Some insertion functions leave point before the inserted text, while
+other functions leave it after. We call the former insertion "after
+point" and the latter insertion "before point".
+
+ If a string with non-`nil' extent data is inserted, the remembered
+extents will also be inserted. *Note Duplicable Extents::.
+
+ Insertion functions signal an error if the current buffer is
+read-only.
+
+ These functions copy text characters from strings and buffers along
+with their properties. The inserted characters have exactly the same
+properties as the characters they were copied from. By contrast,
+characters specified as separate arguments, not part of a string or
+buffer, inherit their text properties from the neighboring text.
+
+ - Function: insert &rest args
+ This function inserts the strings and/or characters ARGS into the
+ current buffer, at point, moving point forward. In other words, it
+ inserts the text before point. An error is signaled unless all
+ ARGS are either strings or characters. The value is `nil'.
+
+ - Function: insert-before-markers &rest args
+ This function inserts the strings and/or characters ARGS into the
+ current buffer, at point, moving point forward. An error is
+ signaled unless all ARGS are either strings or characters. The
+ value is `nil'.
+
+ This function is unlike the other insertion functions in that it
+ relocates markers initially pointing at the insertion point, to
+ point after the inserted text.
+
+ - Function: insert-string string &optional buffer
+ This function inserts STRING into BUFFER before point. BUFFER
+ defaults to the current buffer if omitted. This function is
+ chiefly useful if you want to insert a string in a buffer other
+ than the current one (otherwise you could just use `insert').
+
+ - Function: insert-char character &optional count ignored buffer
+ This function inserts COUNT instances of CHARACTER into BUFFER
+ before point. COUNT must be a number, and CHARACTER must be a
+ character.
+
+ If optional argument BUFFER is `nil', the current buffer is
+ assumed. (In FSF Emacs, the third argument is called INHERIT and
+ refers to text properties. In XEmacs, it is always ignored.)
+
+ This function always returns `nil'.
+
+ - Function: insert-buffer-substring from-buffer-or-name &optional
+ start end
+ This function inserts a portion of buffer FROM-BUFFER-OR-NAME
+ (which must already exist) into the current buffer before point.
+ The text inserted is the region from START and END. (These
+ arguments default to the beginning and end of the accessible
+ portion of that buffer.) This function returns `nil'.
+
+ In this example, the form is executed with buffer `bar' as the
+ current buffer. We assume that buffer `bar' is initially empty.
+
+ ---------- Buffer: foo ----------
+ We hold these truths to be self-evident, that all
+ ---------- Buffer: foo ----------
+
+ (insert-buffer-substring "foo" 1 20)
+ => nil
+
+ ---------- Buffer: bar ----------
+ We hold these truth-!-
+ ---------- Buffer: bar ----------
+
+\1f
+File: lispref.info, Node: Commands for Insertion, Next: Deletion, Prev: Insertion, Up: Text
+
+User-Level Insertion Commands
+=============================
+
+ This section describes higher-level commands for inserting text,
+commands intended primarily for the user but useful also in Lisp
+programs.
+
+ - Command: insert-buffer from-buffer-or-name
+ This command inserts the entire contents of FROM-BUFFER-OR-NAME
+ (which must exist) into the current buffer after point. It leaves
+ the mark after the inserted text. The value is `nil'.
+
+ - Command: self-insert-command count
+ This command inserts the last character typed; it does so COUNT
+ times, before point, and returns `nil'. Most printing characters
+ are bound to this command. In routine use, `self-insert-command'
+ is the most frequently called function in XEmacs, but programs
+ rarely use it except to install it on a keymap.
+
+ In an interactive call, COUNT is the numeric prefix argument.
+
+ This command calls `auto-fill-function' whenever that is non-`nil'
+ and the character inserted is a space or a newline (*note Auto
+ Filling::).
+
+ This command performs abbrev expansion if Abbrev mode is enabled
+ and the inserted character does not have word-constituent syntax.
+ (*Note Abbrevs::, and *Note Syntax Class Table::.)
+
+ This is also responsible for calling `blink-paren-function' when
+ the inserted character has close parenthesis syntax (*note
+ Blinking::).
+
+ - Command: newline &optional count
+ This command inserts newlines into the current buffer before point.
+ If COUNT is supplied, that many newline characters are inserted.
+
+ This function calls `auto-fill-function' if the current column
+ number is greater than the value of `fill-column' and COUNT is
+ `nil'. Typically what `auto-fill-function' does is insert a
+ newline; thus, the overall result in this case is to insert two
+ newlines at different places: one at point, and another earlier in
+ the line. `newline' does not auto-fill if COUNT is non-`nil'.
+
+ This command indents to the left margin if that is not zero.
+ *Note Margins::.
+
+ The value returned is `nil'. In an interactive call, COUNT is the
+ numeric prefix argument.
+
+ - Command: split-line
+ This command splits the current line, moving the portion of the
+ line after point down vertically so that it is on the next line
+ directly below where it was before. Whitespace is inserted as
+ needed at the beginning of the lower line, using the `indent-to'
+ function. `split-line' returns the position of point.
+
+ Programs hardly ever use this function.
+
+ - Variable: overwrite-mode
+ This variable controls whether overwrite mode is in effect: a
+ non-`nil' value enables the mode. It is automatically made
+ buffer-local when set in any fashion.
+
+\1f
+File: lispref.info, Node: Deletion, Next: User-Level Deletion, Prev: Commands for Insertion, Up: Text
+
+Deleting Text
+=============
+
+ Deletion means removing part of the text in a buffer, without saving
+it in the kill ring (*note The Kill Ring::). Deleted text can't be
+yanked, but can be reinserted using the undo mechanism (*note Undo::).
+Some deletion functions do save text in the kill ring in some special
+cases.
+
+ All of the deletion functions operate on the current buffer, and all
+return a value of `nil'.
+
+ - Command: erase-buffer &optional buffer
+ This function deletes the entire text of BUFFER, leaving it empty.
+ If the buffer is read-only, it signals a `buffer-read-only'
+ error. Otherwise, it deletes the text without asking for any
+ confirmation. It returns `nil'. BUFFER defaults to the current
+ buffer if omitted.
+
+ Normally, deleting a large amount of text from a buffer inhibits
+ further auto-saving of that buffer "because it has shrunk".
+ However, `erase-buffer' does not do this, the idea being that the
+ future text is not really related to the former text, and its size
+ should not be compared with that of the former text.
+
+ - Command: delete-region start end &optional buffer
+ This command deletes the text in BUFFER in the region defined by
+ START and END. The value is `nil'. If optional argument BUFFER
+ is `nil', the current buffer is assumed.
+
+ - Command: delete-char count &optional killp
+ This command deletes COUNT characters directly after point, or
+ before point if COUNT is negative. If KILLP is non-`nil', then it
+ saves the deleted characters in the kill ring.
+
+ In an interactive call, COUNT is the numeric prefix argument, and
+ KILLP is the unprocessed prefix argument. Therefore, if a prefix
+ argument is supplied, the text is saved in the kill ring. If no
+ prefix argument is supplied, then one character is deleted, but
+ not saved in the kill ring.
+
+ The value returned is always `nil'.
+
+ - Command: delete-backward-char count &optional killp
+ This command deletes COUNT characters directly before point, or
+ after point if COUNT is negative. If KILLP is non-`nil', then it
+ saves the deleted characters in the kill ring.
+
+ In an interactive call, COUNT is the numeric prefix argument, and
+ KILLP is the unprocessed prefix argument. Therefore, if a prefix
+ argument is supplied, the text is saved in the kill ring. If no
+ prefix argument is supplied, then one character is deleted, but
+ not saved in the kill ring.
+
+ The value returned is always `nil'.
+
+ - Command: backward-delete-char-untabify count &optional killp
+ This command deletes COUNT characters backward, changing tabs into
+ spaces. When the next character to be deleted is a tab, it is
+ first replaced with the proper number of spaces to preserve
+ alignment and then one of those spaces is deleted instead of the
+ tab. If KILLP is non-`nil', then the command saves the deleted
+ characters in the kill ring.
+
+ Conversion of tabs to spaces happens only if COUNT is positive.
+ If it is negative, exactly -COUNT characters after point are
+ deleted.
+
+ In an interactive call, COUNT is the numeric prefix argument, and
+ KILLP is the unprocessed prefix argument. Therefore, if a prefix
+ argument is supplied, the text is saved in the kill ring. If no
+ prefix argument is supplied, then one character is deleted, but
+ not saved in the kill ring.
+
+ The value returned is always `nil'.
+
+\1f
+File: lispref.info, Node: User-Level Deletion, Next: The Kill Ring, Prev: Deletion, Up: Text
+
+User-Level Deletion Commands
+============================
+
+ This section describes higher-level commands for deleting text,
+commands intended primarily for the user but useful also in Lisp
+programs.
+
+ - Command: delete-horizontal-space
+ This function deletes all spaces and tabs around point. It returns
+ `nil'.
+
+ In the following examples, we call `delete-horizontal-space' four
+ times, once on each line, with point between the second and third
+ characters on the line each time.
+
+ ---------- Buffer: foo ----------
+ I -!-thought
+ I -!- thought
+ We-!- thought
+ Yo-!-u thought
+ ---------- Buffer: foo ----------
+
+ (delete-horizontal-space) ; Four times.
+ => nil
+
+ ---------- Buffer: foo ----------
+ Ithought
+ Ithought
+ Wethought
+ You thought
+ ---------- Buffer: foo ----------
+
+ - Command: delete-indentation &optional join-following-p
+ This function joins the line point is on to the previous line,
+ deleting any whitespace at the join and in some cases replacing it
+ with one space. If JOIN-FOLLOWING-P is non-`nil',
+ `delete-indentation' joins this line to the following line
+ instead. The value is `nil'.
+
+ If there is a fill prefix, and the second of the lines being joined
+ starts with the prefix, then `delete-indentation' deletes the fill
+ prefix before joining the lines. *Note Margins::.
+
+ In the example below, point is located on the line starting
+ `events', and it makes no difference if there are trailing spaces
+ in the preceding line.
+
+ ---------- Buffer: foo ----------
+ When in the course of human
+ -!- events, it becomes necessary
+ ---------- Buffer: foo ----------
+
+ (delete-indentation)
+ => nil
+
+ ---------- Buffer: foo ----------
+ When in the course of human-!- events, it becomes necessary
+ ---------- Buffer: foo ----------
+
+ After the lines are joined, the function `fixup-whitespace' is
+ responsible for deciding whether to leave a space at the junction.
+
+ - Command: fixup-whitespace
+ This function replaces all the white space surrounding point with
+ either one space or no space, according to the context. It
+ returns `nil'.
+
+ At the beginning or end of a line, the appropriate amount of space
+ is none. Before a character with close parenthesis syntax, or
+ after a character with open parenthesis or expression-prefix
+ syntax, no space is also appropriate. Otherwise, one space is
+ appropriate. *Note Syntax Class Table::.
+
+ In the example below, `fixup-whitespace' is called the first time
+ with point before the word `spaces' in the first line. For the
+ second invocation, point is directly after the `('.
+
+ ---------- Buffer: foo ----------
+ This has too many -!-spaces
+ This has too many spaces at the start of (-!- this list)
+ ---------- Buffer: foo ----------
+
+ (fixup-whitespace)
+ => nil
+ (fixup-whitespace)
+ => nil
+
+ ---------- Buffer: foo ----------
+ This has too many spaces
+ This has too many spaces at the start of (this list)
+ ---------- Buffer: foo ----------
+
+ - Command: just-one-space
+ This command replaces any spaces and tabs around point with a
+ single space. It returns `nil'.
+
+ - Command: delete-blank-lines
+ This function deletes blank lines surrounding point. If point is
+ on a blank line with one or more blank lines before or after it,
+ then all but one of them are deleted. If point is on an isolated
+ blank line, then it is deleted. If point is on a nonblank line,
+ the command deletes all blank lines following it.
+
+ A blank line is defined as a line containing only tabs and spaces.
+
+ `delete-blank-lines' returns `nil'.
+
+\1f
+File: lispref.info, Node: The Kill Ring, Next: Undo, Prev: User-Level Deletion, Up: Text
+
+The Kill Ring
+=============
+
+ "Kill" functions delete text like the deletion functions, but save
+it so that the user can reinsert it by "yanking". Most of these
+functions have `kill-' in their name. By contrast, the functions whose
+names start with `delete-' normally do not save text for yanking
+(though they can still be undone); these are "deletion" functions.
+
+ Most of the kill commands are primarily for interactive use, and are
+not described here. What we do describe are the functions provided for
+use in writing such commands. You can use these functions to write
+commands for killing text. When you need to delete text for internal
+purposes within a Lisp function, you should normally use deletion
+functions, so as not to disturb the kill ring contents. *Note
+Deletion::.
+
+ Killed text is saved for later yanking in the "kill ring". This is
+a list that holds a number of recent kills, not just the last text
+kill. We call this a "ring" because yanking treats it as having
+elements in a cyclic order. The list is kept in the variable
+`kill-ring', and can be operated on with the usual functions for lists;
+there are also specialized functions, described in this section, that
+treat it as a ring.
+
+ Some people think this use of the word "kill" is unfortunate, since
+it refers to operations that specifically _do not_ destroy the entities
+"killed". This is in sharp contrast to ordinary life, in which death
+is permanent and "killed" entities do not come back to life.
+Therefore, other metaphors have been proposed. For example, the term
+"cut ring" makes sense to people who, in pre-computer days, used
+scissors and paste to cut up and rearrange manuscripts. However, it
+would be difficult to change the terminology now.
+
+* Menu:
+
+* Kill Ring Concepts:: What text looks like in the kill ring.
+* Kill Functions:: Functions that kill text.
+* Yank Commands:: Commands that access the kill ring.
+* Low-Level Kill Ring:: Functions and variables for kill ring access.
+* Internals of Kill Ring:: Variables that hold kill-ring data.
+
+\1f
+File: lispref.info, Node: Kill Ring Concepts, Next: Kill Functions, Up: The Kill Ring
+
+Kill Ring Concepts
+------------------
+
+ The kill ring records killed text as strings in a list, most recent
+first. A short kill ring, for example, might look like this:
+
+ ("some text" "a different piece of text" "even older text")
+
+When the list reaches `kill-ring-max' entries in length, adding a new
+entry automatically deletes the last entry.
+
+ When kill commands are interwoven with other commands, each kill
+command makes a new entry in the kill ring. Multiple kill commands in
+succession build up a single entry in the kill ring, which would be
+yanked as a unit; the second and subsequent consecutive kill commands
+add text to the entry made by the first one.
+
+ For yanking, one entry in the kill ring is designated the "front" of
+the ring. Some yank commands "rotate" the ring by designating a
+different element as the "front." But this virtual rotation doesn't
+change the list itself--the most recent entry always comes first in the
+list.
+
+\1f
+File: lispref.info, Node: Kill Functions, Next: Yank Commands, Prev: Kill Ring Concepts, Up: The Kill Ring
+
+Functions for Killing
+---------------------
+
+ `kill-region' is the usual subroutine for killing text. Any command
+that calls this function is a "kill command" (and should probably have
+`kill' in its name). `kill-region' puts the newly killed text in a new
+element at the beginning of the kill ring or adds it to the most recent
+element. It uses the `last-command' variable to determine whether the
+previous command was a kill command, and if so appends the killed text
+to the most recent entry.
+
+ - Command: kill-region start end &optional verbose
+ This function kills the text in the region defined by START and
+ END. The text is deleted but saved in the kill ring, along with
+ its text properties. The value is always `nil'.
+
+ In an interactive call, START and END are point and the mark.
+
+ If the buffer is read-only, `kill-region' modifies the kill ring
+ just the same, then signals an error without modifying the buffer.
+ This is convenient because it lets the user use all the kill
+ commands to copy text into the kill ring from a read-only buffer.
+
+ - Command: copy-region-as-kill start end
+ This command saves the region defined by START and END on the kill
+ ring (including text properties), but does not delete the text
+ from the buffer. It returns `nil'. It also indicates the extent
+ of the text copied by moving the cursor momentarily, or by
+ displaying a message in the echo area.
+
+ The command does not set `this-command' to `kill-region', so a
+ subsequent kill command does not append to the same kill ring
+ entry.
+
+ Don't call `copy-region-as-kill' in Lisp programs unless you aim to
+ support Emacs 18. For Emacs 19, it is better to use `kill-new' or
+ `kill-append' instead. *Note Low-Level Kill Ring::.
+
+\1f
+File: lispref.info, Node: Yank Commands, Next: Low-Level Kill Ring, Prev: Kill Functions, Up: The Kill Ring
+
+Functions for Yanking
+---------------------
+
+ "Yanking" means reinserting an entry of previously killed text from
+the kill ring. The text properties are copied too.
+
+ - Command: yank &optional arg
+ This command inserts before point the text in the first entry in
+ the kill ring. It positions the mark at the beginning of that
+ text, and point at the end.
+
+ If ARG is a list (which occurs interactively when the user types
+ `C-u' with no digits), then `yank' inserts the text as described
+ above, but puts point before the yanked text and puts the mark
+ after it.
+
+ If ARG is a number, then `yank' inserts the ARGth most recently
+ killed text--the ARGth element of the kill ring list.
+
+ `yank' does not alter the contents of the kill ring or rotate it.
+ It returns `nil'.
+
+ - Command: yank-pop arg
+ This command replaces the just-yanked entry from the kill ring
+ with a different entry from the kill ring.
+
+ This is allowed only immediately after a `yank' or another
+ `yank-pop'. At such a time, the region contains text that was just
+ inserted by yanking. `yank-pop' deletes that text and inserts in
+ its place a different piece of killed text. It does not add the
+ deleted text to the kill ring, since it is already in the kill
+ ring somewhere.
+
+ If ARG is `nil', then the replacement text is the previous element
+ of the kill ring. If ARG is numeric, the replacement is the ARGth
+ previous kill. If ARG is negative, a more recent kill is the
+ replacement.
+
+ The sequence of kills in the kill ring wraps around, so that after
+ the oldest one comes the newest one, and before the newest one
+ goes the oldest.
+
+ The value is always `nil'.
+
+\1f
+File: lispref.info, Node: Low-Level Kill Ring, Next: Internals of Kill Ring, Prev: Yank Commands, Up: The Kill Ring
+
+Low-Level Kill Ring
+-------------------
+
+ These functions and variables provide access to the kill ring at a
+lower level, but still convenient for use in Lisp programs. They take
+care of interaction with X Window selections. They do not exist in
+Emacs version 18.
+
+ - Function: current-kill count &optional do-not-move
+ The function `current-kill' rotates the yanking pointer which
+ designates the "front" of the kill ring by COUNT places (from newer
+ kills to older ones), and returns the text at that place in the
+ ring.
+
+ If the optional second argument DO-NOT-MOVE is non-`nil', then
+ `current-kill' doesn't alter the yanking pointer; it just returns
+ the COUNTth kill, counting from the current yanking pointer.
+
+ If COUNT is zero, indicating a request for the latest kill,
+ `current-kill' calls the value of `interprogram-paste-function'
+ (documented below) before consulting the kill ring.
+
+ - Function: kill-new string &optional replace
+ This function makes the text STRING the latest entry in the kill
+ ring, and sets `kill-ring-yank-pointer' to point to it.
+
+ Normally, STRING is added to the front of the kill ring as a new
+ entry. However, if optional argument REPLACE is non-`nil', the
+ entry previously at the front of the kill ring is discarded, and
+ STRING replaces it.
+
+ This function runs the functions on `kill-hooks', and also invokes
+ the value of `interprogram-cut-function' (see below).
+
+ - Function: kill-append string before-p
+ This function appends the text STRING to the first entry in the
+ kill ring. Normally STRING goes at the end of the entry, but if
+ BEFORE-P is non-`nil', it goes at the beginning. This function
+ also invokes the value of `interprogram-cut-function' (see below).
+
+ - Variable: interprogram-paste-function
+ This variable provides a way of transferring killed text from other
+ programs, when you are using a window system. Its value should be
+ `nil' or a function of no arguments.
+
+ If the value is a function, `current-kill' calls it to get the
+ "most recent kill". If the function returns a non-`nil' value,
+ then that value is used as the "most recent kill". If it returns
+ `nil', then the first element of `kill-ring' is used.
+
+ The normal use of this hook is to get the X server's primary
+ selection as the most recent kill, even if the selection belongs
+ to another X client. *Note X Selections::.
+
+ - Variable: interprogram-cut-function
+ This variable provides a way of communicating killed text to other
+ programs, when you are using a window system. Its value should be
+ `nil' or a function of one argument.
+
+ If the value is a function, `kill-new' and `kill-append' call it
+ with the new first element of the kill ring as an argument.
+
+ The normal use of this hook is to set the X server's primary
+ selection to the newly killed text.
+
+\1f
File: lispref.info, Node: Internals of Kill Ring, Prev: Low-Level Kill Ring, Up: The Kill Ring
Internals of the Kill Ring
commands use these entries to record where point was before the
command.
-`(BEG . END)'
+`(START . END)'
This kind of element indicates how to delete text that was
- inserted. Upon insertion, the text occupied the range BEG-END in
- the buffer.
+ inserted. Upon insertion, the text occupied the range START-END
+ in the buffer.
`(TEXT . POSITION)'
This kind of element indicates how to reinsert text that was
once again; it does so only if the file's modification time
matches those numbers.
-`(nil PROPERTY VALUE BEG . END)'
+`(nil PROPERTY VALUE START . END)'
This kind of element records a change in a text property. Here's
how you might undo the change:
- (put-text-property BEG END PROPERTY VALUE)
+ (put-text-property START END PROPERTY VALUE)
`POSITION'
This element indicates where point was at an earlier time.
In an interactive call, BUFFER-OR-NAME is the current buffer. You
cannot specify any other buffer.
- - Function: buffer-disable-undo &optional buffer
- - Function: buffer-flush-undo &optional buffer
+ - Command: buffer-disable-undo &optional buffer
+ - Command: buffer-flush-undo &optional buffer
This function discards the undo list of BUFFER, and disables
further recording of undo information. As a result, it is no
longer possible to undo either previous changes or any subsequent
If FORCE is non-`nil', that says to fix the line's indentation if
that doesn't match the left margin value.
- - Function: delete-to-left-margin from to
+ - Function: delete-to-left-margin &optional from to
This function removes left margin indentation from the text
between FROM and TO. The amount of indentation to delete is
determined by calling `current-left-margin'. In no case does this
function delete non-whitespace.
+ The arguments FROM and TO are optional; the default is the whole
+ buffer.
+
- Function: indent-to-left-margin
This is the default `indent-line-function', used in Fundamental
mode, Text mode, etc. Its effect is to adjust the indentation at
standard convention for hooks, it was renamed to
`auto-fill-function' in version 19.
-\1f
-File: lispref.info, Node: Sorting, Next: Columns, Prev: Auto Filling, Up: Text
-
-Sorting Text
-============
-
- The sorting functions described in this section all rearrange text in
-a buffer. This is in contrast to the function `sort', which rearranges
-the order of the elements of a list (*note Rearrangement::). The
-values returned by these functions are not meaningful.
-
- - Function: sort-subr reverse nextrecfun endrecfun &optional
- startkeyfun endkeyfun
- This function is the general text-sorting routine that divides a
- buffer into records and sorts them. Most of the commands in this
- section use this function.
-
- To understand how `sort-subr' works, consider the whole accessible
- portion of the buffer as being divided into disjoint pieces called
- "sort records". The records may or may not be contiguous; they may
- not overlap. A portion of each sort record (perhaps all of it) is
- designated as the sort key. Sorting rearranges the records in
- order by their sort keys.
-
- Usually, the records are rearranged in order of ascending sort key.
- If the first argument to the `sort-subr' function, REVERSE, is
- non-`nil', the sort records are rearranged in order of descending
- sort key.
-
- The next four arguments to `sort-subr' are functions that are
- called to move point across a sort record. They are called many
- times from within `sort-subr'.
-
- 1. NEXTRECFUN is called with point at the end of a record. This
- function moves point to the start of the next record. The
- first record is assumed to start at the position of point
- when `sort-subr' is called. Therefore, you should usually
- move point to the beginning of the buffer before calling
- `sort-subr'.
-
- This function can indicate there are no more sort records by
- leaving point at the end of the buffer.
-
- 2. ENDRECFUN is called with point within a record. It moves
- point to the end of the record.
-
- 3. STARTKEYFUN is called to move point from the start of a
- record to the start of the sort key. This argument is
- optional; if it is omitted, the whole record is the sort key.
- If supplied, the function should either return a non-`nil'
- value to be used as the sort key, or return `nil' to indicate
- that the sort key is in the buffer starting at point. In the
- latter case, ENDKEYFUN is called to find the end of the sort
- key.
-
- 4. ENDKEYFUN is called to move point from the start of the sort
- key to the end of the sort key. This argument is optional.
- If STARTKEYFUN returns `nil' and this argument is omitted (or
- `nil'), then the sort key extends to the end of the record.
- There is no need for ENDKEYFUN if STARTKEYFUN returns a
- non-`nil' value.
-
- As an example of `sort-subr', here is the complete function
- definition for `sort-lines':
-
- ;; Note that the first two lines of doc string
- ;; are effectively one line when viewed by a user.
- (defun sort-lines (reverse beg end)
- "Sort lines in region alphabetically.
- Called from a program, there are three arguments:
- REVERSE (non-nil means reverse order),
- and BEG and END (the region to sort)."
- (interactive "P\nr")
- (save-restriction
- (narrow-to-region beg end)
- (goto-char (point-min))
- (sort-subr reverse
- 'forward-line
- 'end-of-line)))
-
- Here `forward-line' moves point to the start of the next record,
- and `end-of-line' moves point to the end of record. We do not pass
- the arguments STARTKEYFUN and ENDKEYFUN, because the entire record
- is used as the sort key.
-
- The `sort-paragraphs' function is very much the same, except that
- its `sort-subr' call looks like this:
-
- (sort-subr reverse
- (function
- (lambda ()
- (skip-chars-forward "\n \t\f")))
- 'forward-paragraph)
-
- - Command: sort-regexp-fields reverse record-regexp key-regexp start
- end
- This command sorts the region between START and END alphabetically
- as specified by RECORD-REGEXP and KEY-REGEXP. If REVERSE is a
- negative integer, then sorting is in reverse order.
-
- Alphabetical sorting means that two sort keys are compared by
- comparing the first characters of each, the second characters of
- each, and so on. If a mismatch is found, it means that the sort
- keys are unequal; the sort key whose character is less at the
- point of first mismatch is the lesser sort key. The individual
- characters are compared according to their numerical values.
- Since Emacs uses the ASCII character set, the ordering in that set
- determines alphabetical order.
-
- The value of the RECORD-REGEXP argument specifies how to divide
- the buffer into sort records. At the end of each record, a search
- is done for this regular expression, and the text that matches it
- is the next record. For example, the regular expression `^.+$',
- which matches lines with at least one character besides a newline,
- would make each such line into a sort record. *Note Regular
- Expressions::, for a description of the syntax and meaning of
- regular expressions.
-
- The value of the KEY-REGEXP argument specifies what part of each
- record is the sort key. The KEY-REGEXP could match the whole
- record, or only a part. In the latter case, the rest of the
- record has no effect on the sorted order of records, but it is
- carried along when the record moves to its new position.
-
- The KEY-REGEXP argument can refer to the text matched by a
- subexpression of RECORD-REGEXP, or it can be a regular expression
- on its own.
-
- If KEY-REGEXP is:
-
- `\DIGIT'
- then the text matched by the DIGITth `\(...\)' parenthesis
- grouping in RECORD-REGEXP is the sort key.
-
- `\&'
- then the whole record is the sort key.
-
- a regular expression
- then `sort-regexp-fields' searches for a match for the regular
- expression within the record. If such a match is found, it
- is the sort key. If there is no match for KEY-REGEXP within
- a record then that record is ignored, which means its
- position in the buffer is not changed. (The other records
- may move around it.)
-
- For example, if you plan to sort all the lines in the region by the
- first word on each line starting with the letter `f', you should
- set RECORD-REGEXP to `^.*$' and set KEY-REGEXP to `\<f\w*\>'. The
- resulting expression looks like this:
-
- (sort-regexp-fields nil "^.*$" "\\<f\\w*\\>"
- (region-beginning)
- (region-end))
-
- If you call `sort-regexp-fields' interactively, it prompts for
- RECORD-REGEXP and KEY-REGEXP in the minibuffer.
-
- - Command: sort-lines reverse start end
- This command alphabetically sorts lines in the region between
- START and END. If REVERSE is non-`nil', the sort is in reverse
- order.
-
- - Command: sort-paragraphs reverse start end
- This command alphabetically sorts paragraphs in the region between
- START and END. If REVERSE is non-`nil', the sort is in reverse
- order.
-
- - Command: sort-pages reverse start end
- This command alphabetically sorts pages in the region between
- START and END. If REVERSE is non-`nil', the sort is in reverse
- order.
-
- - Command: sort-fields field start end
- This command sorts lines in the region between START and END,
- comparing them alphabetically by the FIELDth field of each line.
- Fields are separated by whitespace and numbered starting from 1.
- If FIELD is negative, sorting is by the -FIELDth field from the
- end of the line. This command is useful for sorting tables.
-
- - Command: sort-numeric-fields field start end
- This command sorts lines in the region between START and END,
- comparing them numerically by the FIELDth field of each line. The
- specified field must contain a number in each line of the region.
- Fields are separated by whitespace and numbered starting from 1.
- If FIELD is negative, sorting is by the -FIELDth field from the
- end of the line. This command is useful for sorting tables.
-
- - Command: sort-columns reverse &optional beg end
- This command sorts the lines in the region between BEG and END,
- comparing them alphabetically by a certain range of columns. The
- column positions of BEG and END bound the range of columns to sort
- on.
-
- If REVERSE is non-`nil', the sort is in reverse order.
-
- One unusual thing about this command is that the entire line
- containing position BEG, and the entire line containing position
- END, are included in the region sorted.
-
- Note that `sort-columns' uses the `sort' utility program, and so
- cannot work properly on text containing tab characters. Use `M-x
- `untabify'' to convert tabs to spaces before sorting.
-
-\1f
-File: lispref.info, Node: Columns, Next: Indentation, Prev: Sorting, Up: Text
-
-Counting Columns
-================
-
- The column functions convert between a character position (counting
-characters from the beginning of the buffer) and a column position
-(counting screen characters from the beginning of a line).
-
- A character counts according to the number of columns it occupies on
-the screen. This means control characters count as occupying 2 or 4
-columns, depending upon the value of `ctl-arrow', and tabs count as
-occupying a number of columns that depends on the value of `tab-width'
-and on the column where the tab begins. *Note Usual Display::.
-
- Column number computations ignore the width of the window and the
-amount of horizontal scrolling. Consequently, a column value can be
-arbitrarily high. The first (or leftmost) column is numbered 0.
-
- - Function: current-column
- This function returns the horizontal position of point, measured in
- columns, counting from 0 at the left margin. The column position
- is the sum of the widths of all the displayed representations of
- the characters between the start of the current line and point.
-
- For an example of using `current-column', see the description of
- `count-lines' in *Note Text Lines::.
-
- - Function: move-to-column column &optional force
- This function moves point to COLUMN in the current line. The
- calculation of COLUMN takes into account the widths of the
- displayed representations of the characters between the start of
- the line and point.
-
- If column COLUMN is beyond the end of the line, point moves to the
- end of the line. If COLUMN is negative, point moves to the
- beginning of the line.
-
- If it is impossible to move to column COLUMN because that is in
- the middle of a multicolumn character such as a tab, point moves
- to the end of that character. However, if FORCE is non-`nil', and
- COLUMN is in the middle of a tab, then `move-to-column' converts
- the tab into spaces so that it can move precisely to column
- COLUMN. Other multicolumn characters can cause anomalies despite
- FORCE, since there is no way to split them.
-
- The argument FORCE also has an effect if the line isn't long
- enough to reach column COLUMN; in that case, it says to add
- whitespace at the end of the line to reach that column.
-
- If COLUMN is not an integer, an error is signaled.
-
- The return value is the column number actually moved to.
-
-\1f
-File: lispref.info, Node: Indentation, Next: Case Changes, Prev: Columns, Up: Text
-
-Indentation
-===========
-
- The indentation functions are used to examine, move to, and change
-whitespace that is at the beginning of a line. Some of the functions
-can also change whitespace elsewhere on a line. Columns and indentation
-count from zero at the left margin.
-
-* Menu:
-
-* Primitive Indent:: Functions used to count and insert indentation.
-* Mode-Specific Indent:: Customize indentation for different modes.
-* Region Indent:: Indent all the lines in a region.
-* Relative Indent:: Indent the current line based on previous lines.
-* Indent Tabs:: Adjustable, typewriter-like tab stops.
-* Motion by Indent:: Move to first non-blank character.
-
-\1f
-File: lispref.info, Node: Primitive Indent, Next: Mode-Specific Indent, Up: Indentation
-
-Indentation Primitives
-----------------------
-
- This section describes the primitive functions used to count and
-insert indentation. The functions in the following sections use these
-primitives.
-
- - Function: current-indentation
- This function returns the indentation of the current line, which is
- the horizontal position of the first nonblank character. If the
- contents are entirely blank, then this is the horizontal position
- of the end of the line.
-
- - Command: indent-to column &optional minimum
- This function indents from point with tabs and spaces until COLUMN
- is reached. If MINIMUM is specified and non-`nil', then at least
- that many spaces are inserted even if this requires going beyond
- COLUMN. Otherwise the function does nothing if point is already
- beyond COLUMN. The value is the column at which the inserted
- indentation ends.
-
- - User Option: indent-tabs-mode
- If this variable is non-`nil', indentation functions can insert
- tabs as well as spaces. Otherwise, they insert only spaces.
- Setting this variable automatically makes it local to the current
- buffer.
-
-\1f
-File: lispref.info, Node: Mode-Specific Indent, Next: Region Indent, Prev: Primitive Indent, Up: Indentation
-
-Indentation Controlled by Major Mode
-------------------------------------
-
- An important function of each major mode is to customize the <TAB>
-key to indent properly for the language being edited. This section
-describes the mechanism of the <TAB> key and how to control it. The
-functions in this section return unpredictable values.
-
- - Variable: indent-line-function
- This variable's value is the function to be used by <TAB> (and
- various commands) to indent the current line. The command
- `indent-according-to-mode' does no more than call this function.
-
- In Lisp mode, the value is the symbol `lisp-indent-line'; in C
- mode, `c-indent-line'; in Fortran mode, `fortran-indent-line'. In
- Fundamental mode, Text mode, and many other modes with no standard
- for indentation, the value is `indent-to-left-margin' (which is the
- default value).
-
- - Command: indent-according-to-mode
- This command calls the function in `indent-line-function' to
- indent the current line in a way appropriate for the current major
- mode.
-
- - Command: indent-for-tab-command
- This command calls the function in `indent-line-function' to indent
- the current line; except that if that function is
- `indent-to-left-margin', it calls `insert-tab' instead. (That is
- a trivial command that inserts a tab character.)
-
- - Command: newline-and-indent
- This function inserts a newline, then indents the new line (the one
- following the newline just inserted) according to the major mode.
-
- It does indentation by calling the current `indent-line-function'.
- In programming language modes, this is the same thing <TAB> does,
- but in some text modes, where <TAB> inserts a tab,
- `newline-and-indent' indents to the column specified by
- `left-margin'.
-
- - Command: reindent-then-newline-and-indent
- This command reindents the current line, inserts a newline at
- point, and then reindents the new line (the one following the
- newline just inserted).
-
- This command does indentation on both lines according to the
- current major mode, by calling the current value of
- `indent-line-function'. In programming language modes, this is
- the same thing <TAB> does, but in some text modes, where <TAB>
- inserts a tab, `reindent-then-newline-and-indent' indents to the
- column specified by `left-margin'.
-
-\1f
-File: lispref.info, Node: Region Indent, Next: Relative Indent, Prev: Mode-Specific Indent, Up: Indentation
-
-Indenting an Entire Region
---------------------------
-
- This section describes commands that indent all the lines in the
-region. They return unpredictable values.
-
- - Command: indent-region start end to-column
- This command indents each nonblank line starting between START
- (inclusive) and END (exclusive). If TO-COLUMN is `nil',
- `indent-region' indents each nonblank line by calling the current
- mode's indentation function, the value of `indent-line-function'.
-
- If TO-COLUMN is non-`nil', it should be an integer specifying the
- number of columns of indentation; then this function gives each
- line exactly that much indentation, by either adding or deleting
- whitespace.
-
- If there is a fill prefix, `indent-region' indents each line by
- making it start with the fill prefix.
-
- - Variable: indent-region-function
- The value of this variable is a function that can be used by
- `indent-region' as a short cut. You should design the function so
- that it will produce the same results as indenting the lines of the
- region one by one, but presumably faster.
-
- If the value is `nil', there is no short cut, and `indent-region'
- actually works line by line.
-
- A short-cut function is useful in modes such as C mode and Lisp
- mode, where the `indent-line-function' must scan from the
- beginning of the function definition: applying it to each line
- would be quadratic in time. The short cut can update the scan
- information as it moves through the lines indenting them; this
- takes linear time. In a mode where indenting a line individually
- is fast, there is no need for a short cut.
-
- `indent-region' with a non-`nil' argument TO-COLUMN has a
- different meaning and does not use this variable.
-
- - Command: indent-rigidly start end count
- This command indents all lines starting between START (inclusive)
- and END (exclusive) sideways by COUNT columns. This "preserves
- the shape" of the affected region, moving it as a rigid unit.
- Consequently, this command is useful not only for indenting
- regions of unindented text, but also for indenting regions of
- formatted code.
-
- For example, if COUNT is 3, this command adds 3 columns of
- indentation to each of the lines beginning in the region specified.
-
- In Mail mode, `C-c C-y' (`mail-yank-original') uses
- `indent-rigidly' to indent the text copied from the message being
- replied to.
-
- - Function: indent-code-rigidly start end columns &optional
- nochange-regexp
- This is like `indent-rigidly', except that it doesn't alter lines
- that start within strings or comments.
-
- In addition, it doesn't alter a line if NOCHANGE-REGEXP matches at
- the beginning of the line (if NOCHANGE-REGEXP is non-`nil').
-
-\1f
-File: lispref.info, Node: Relative Indent, Next: Indent Tabs, Prev: Region Indent, Up: Indentation
-
-Indentation Relative to Previous Lines
---------------------------------------
-
- This section describes two commands that indent the current line
-based on the contents of previous lines.
-
- - Command: indent-relative &optional unindented-ok
- This command inserts whitespace at point, extending to the same
- column as the next "indent point" of the previous nonblank line.
- An indent point is a non-whitespace character following
- whitespace. The next indent point is the first one at a column
- greater than the current column of point. For example, if point
- is underneath and to the left of the first non-blank character of
- a line of text, it moves to that column by inserting whitespace.
-
- If the previous nonblank line has no next indent point (i.e., none
- at a great enough column position), `indent-relative' either does
- nothing (if UNINDENTED-OK is non-`nil') or calls
- `tab-to-tab-stop'. Thus, if point is underneath and to the right
- of the last column of a short line of text, this command ordinarily
- moves point to the next tab stop by inserting whitespace.
-
- The return value of `indent-relative' is unpredictable.
-
- In the following example, point is at the beginning of the second
- line:
-
- This line is indented twelve spaces.
- -!-The quick brown fox jumped.
-
- Evaluation of the expression `(indent-relative nil)' produces the
- following:
-
- This line is indented twelve spaces.
- -!-The quick brown fox jumped.
-
- In this example, point is between the `m' and `p' of `jumped':
-
- This line is indented twelve spaces.
- The quick brown fox jum-!-ped.
-
- Evaluation of the expression `(indent-relative nil)' produces the
- following:
-
- This line is indented twelve spaces.
- The quick brown fox jum -!-ped.
-
- - Command: indent-relative-maybe
- This command indents the current line like the previous nonblank
- line. It calls `indent-relative' with `t' as the UNINDENTED-OK
- argument. The return value is unpredictable.
-
- If the previous nonblank line has no indent points beyond the
- current column, this command does nothing.
-
-\1f
-File: lispref.info, Node: Indent Tabs, Next: Motion by Indent, Prev: Relative Indent, Up: Indentation
-
-Adjustable "Tab Stops"
-----------------------
-
- This section explains the mechanism for user-specified "tab stops"
-and the mechanisms that use and set them. The name "tab stops" is used
-because the feature is similar to that of the tab stops on a
-typewriter. The feature works by inserting an appropriate number of
-spaces and tab characters to reach the next tab stop column; it does not
-affect the display of tab characters in the buffer (*note Usual
-Display::). Note that the <TAB> character as input uses this tab stop
-feature only in a few major modes, such as Text mode.
-
- - Command: tab-to-tab-stop
- This command inserts spaces or tabs up to the next tab stop column
- defined by `tab-stop-list'. It searches the list for an element
- greater than the current column number, and uses that element as
- the column to indent to. It does nothing if no such element is
- found.
-
- - User Option: tab-stop-list
- This variable is the list of tab stop columns used by
- `tab-to-tab-stops'. The elements should be integers in increasing
- order. The tab stop columns need not be evenly spaced.
-
- Use `M-x edit-tab-stops' to edit the location of tab stops
- interactively.
-
-\1f
-File: lispref.info, Node: Motion by Indent, Prev: Indent Tabs, Up: Indentation
-
-Indentation-Based Motion Commands
----------------------------------
-
- These commands, primarily for interactive use, act based on the
-indentation in the text.
-
- - Command: back-to-indentation
- This command moves point to the first non-whitespace character in
- the current line (which is the line in which point is located).
- It returns `nil'.
-
- - Command: backward-to-indentation arg
- This command moves point backward ARG lines and then to the first
- nonblank character on that line. It returns `nil'.
-
- - Command: forward-to-indentation arg
- This command moves point forward ARG lines and then to the first
- nonblank character on that line. It returns `nil'.
-
-\1f
-File: lispref.info, Node: Case Changes, Next: Text Properties, Prev: Indentation, Up: Text
-
-Case Changes
-============
-
- The case change commands described here work on text in the current
-buffer. *Note Character Case::, for case conversion commands that work
-on strings and characters. *Note Case Tables::, for how to customize
-which characters are upper or lower case and how to convert them.
-
- - Command: capitalize-region start end
- This function capitalizes all words in the region defined by START
- and END. To capitalize means to convert each word's first
- character to upper case and convert the rest of each word to lower
- case. The function returns `nil'.
-
- If one end of the region is in the middle of a word, the part of
- the word within the region is treated as an entire word.
-
- When `capitalize-region' is called interactively, START and END
- are point and the mark, with the smallest first.
-
- ---------- Buffer: foo ----------
- This is the contents of the 5th foo.
- ---------- Buffer: foo ----------
-
- (capitalize-region 1 44)
- => nil
-
- ---------- Buffer: foo ----------
- This Is The Contents Of The 5th Foo.
- ---------- Buffer: foo ----------
-
- - Command: downcase-region start end
- This function converts all of the letters in the region defined by
- START and END to lower case. The function returns `nil'.
-
- When `downcase-region' is called interactively, START and END are
- point and the mark, with the smallest first.
-
- - Command: upcase-region start end
- This function converts all of the letters in the region defined by
- START and END to upper case. The function returns `nil'.
-
- When `upcase-region' is called interactively, START and END are
- point and the mark, with the smallest first.
-
- - Command: capitalize-word count
- This function capitalizes COUNT words after point, moving point
- over as it does. To capitalize means to convert each word's first
- character to upper case and convert the rest of each word to lower
- case. If COUNT is negative, the function capitalizes the -COUNT
- previous words but does not move point. The value is `nil'.
-
- If point is in the middle of a word, the part of the word before
- point is ignored when moving forward. The rest is treated as an
- entire word.
-
- When `capitalize-word' is called interactively, COUNT is set to
- the numeric prefix argument.
-
- - Command: downcase-word count
- This function converts the COUNT words after point to all lower
- case, moving point over as it does. If COUNT is negative, it
- converts the -COUNT previous words but does not move point. The
- value is `nil'.
-
- When `downcase-word' is called interactively, COUNT is set to the
- numeric prefix argument.
-
- - Command: upcase-word count
- This function converts the COUNT words after point to all upper
- case, moving point over as it does. If COUNT is negative, it
- converts the -COUNT previous words but does not move point. The
- value is `nil'.
-
- When `upcase-word' is called interactively, COUNT is set to the
- numeric prefix argument.
-
-\1f
-File: lispref.info, Node: Text Properties, Next: Substitution, Prev: Case Changes, Up: Text
-
-Text Properties
-===============
-
- Text properties are an alternative interface to extents (*note
-Extents::), and are built on top of them. They are useful when you
-want to view textual properties as being attached to the characters
-themselves rather than to intervals of characters. The text property
-interface is compatible with FSF Emacs.
-
- Each character position in a buffer or a string can have a "text
-property list", much like the property list of a symbol (*note Property
-Lists::). The properties belong to a particular character at a
-particular place, such as, the letter `T' at the beginning of this
-sentence or the first `o' in `foo'--if the same character occurs in two
-different places, the two occurrences generally have different
-properties.
-
- Each property has a name and a value. Both of these can be any Lisp
-object, but the name is normally a symbol. The usual way to access the
-property list is to specify a name and ask what value corresponds to it.
-
- Note that FSF Emacs also looks at the `category' property to find
-defaults for text properties. We consider this too bogus to implement.
-
- Copying text between strings and buffers preserves the properties
-along with the characters; this includes such diverse functions as
-`substring', `insert', and `buffer-substring'.
-
-* Menu:
-
-* Examining Properties:: Looking at the properties of one character.
-* Changing Properties:: Setting the properties of a range of text.
-* Property Search:: Searching for where a property changes value.
-* Special Properties:: Particular properties with special meanings.
-* Saving Properties:: Saving text properties in files, and reading
- them back.
-
projects / chise / xemacs-chise.git / blobdiff