Provided by: tk8.4-doc_8.4.19-4_all bug

NAME

       text, tk_textCopy, tk_textCut, tk_textPaste - Create and manipulate text widgets

SYNOPSIS

       text pathName ?options?
       tk_textCopy pathNametk_textCut pathNametk_textPaste pathName

STANDARD OPTIONS

       -background           -highlightthickness  -relief
       -borderwidth          -insertbackground    -selectbackground
       -cursor               -insertborderwidth   -selectborderwidth
       -exportselection      -insertofftime       -selectforeground
       -font                 -insertontime        -setgrid
       -foreground           -insertwidth         -takefocus
       -highlightbackground  -padx                -xscrollcommand
       -highlightcolor       -pady                -yscrollcommand

       See the options manual entry for details on the standard options.

WIDGET-SPECIFIC OPTIONS

       [-autoseparators autoSeparators]  Specifies  a  boolean  that  says whether separators are │
       automatically inserted in the undo stack. Only meaningful when the -undo option  is  true.
       [-height height]  Specifies  the  desired height for the window, in units of characters in
       the font given by the -font option.  Must be at least one.   [-maxundo maxUndo]  Specifies │
       the  maximum number of compound undo actions on the undo stack. A zero or a negative value │
       imply an unlimited undo stack.  [-spacing1 spacing1] Requests additional space above  each
       text  line in the widget, using any of the standard forms for screen distances.  If a line
       wraps, this option only applies to the first line on the  display.   This  option  may  be
       overridden  with  -spacing1 options in tags.  [-spacing2 spacing2] For lines that wrap (so
       that they cover more than one line on the display) this option specifies additional  space
       to  provide between the display lines that represent a single line of text.  The value may
       have any of the standard forms for screen distances.  This option may be  overridden  with
       -spacing2 options in tags.  [-spacing3 spacing3] Requests additional space below each text
       line in the widget, using any of the standard forms  for  screen  distances.   If  a  line
       wraps,  this  option  only  applies  to  the last line on the display.  This option may be
       overridden with -spacing3 options in tags.  [-state state] Specifies one of two states for
       the  text:   normal  or  disabled.   If  the  text  is disabled then characters may not be
       inserted or deleted and no insertion cursor will be displayed, even if the input focus  is
       in  the  widget.   [-tabs tabs] Specifies a set of tab stops for the window.  The option's
       value consists of a list of screen distances giving the positions of the tab  stops,  each
       of  which  is  a  distance  relative  to  the  left edge of the widget (excluding borders,
       padding, etc).  Each position may optionally be followed in the next list element  by  one
       of  the  keywords  left,  right,  center,  or numeric, which specifies how to justify text
       relative to the tab stop.  Left is the default; it  causes  the  text  following  the  tab
       character  to  be positioned with its left edge at the tab position.  Right means that the
       right edge of the text following the tab character is positioned at the tab position,  and
       center  means  that  the  text  is  centered  at the tab position.  Numeric means that the
       decimal point in the text is positioned at the tab position;  if there is no decimal point
       then  the  least significant digit of the number is positioned just to the left of the tab
       position;  if there is no number in the text then the text is right-justified at  the  tab
       position.   For  example,  -tabs  {2c  left  4c 6c center} creates three tab stops at two-
       centimeter intervals;  the first two use left justification  and  the  third  uses  center
       justification.  If the list of tab stops does not have enough elements to cover all of the
       tabs in a text line, then Tk extrapolates new tab stops using the  spacing  and  alignment
       from  the  last  tab  stop in the list.  Tab distances must be strictly positive, and must
       always increase from one tab stop to the next (if not, an error is thrown).  The value  of
       the  tabs  option  may  be  overridden  by  -tabs  options in tags.  If no -tabs option is
       specified, or if it is specified as an empty list, then Tk uses default tabs spaced  every
       eight  (average  size) characters.  [-undo undo] Specifies a boolean that says whether the │
       undo mechanism is active or not.  [-width width]  Specifies  the  desired  width  for  the
       window  in units of characters in the font given by the -font option.  If the font doesn't
       have a uniform width then the width of the character ``0'' is  used  in  translating  from
       character  units  to screen units.  [-wrap wrap] Specifies how to handle lines in the text
       that are too long to be displayed in a single line of the text's window.  The  value  must
       be  none  or  char  or  word.  A wrap mode of none means that each line of text appears as
       exactly one line on the screen;  extra characters that don't fit on  the  screen  are  not
       displayed.   In  the  other  modes each line of text will be broken up into several screen
       lines if necessary to keep all the characters visible.  In char mode a screen  line  break
       may  occur  after  any  character;  in  word  mode  a line break will only be made at word
       boundaries.
_________________________________________________________________

DESCRIPTION

       The text command creates a new window (given by the pathName argument) and makes it into a
       text widget.  Additional options, described above, may be specified on the command line or
       in the option database to configure aspects of the text such  as  its  default  background
       color and relief.  The text command returns the path name of the new window.

       A  text widget displays one or more lines of text and allows that text to be edited.  Text
       widgets support four different kinds of annotations  on  the  text,  called  tags,  marks,
       embedded  windows  or  embedded  images.   Tags allow different portions of the text to be
       displayed with different fonts and colors.  In addition, Tcl commands  can  be  associated
       with tags so that scripts are invoked when particular actions such as keystrokes and mouse
       button presses occur in particular ranges of the text.  See TAGS below for more details.

       The second form of annotation consists of floating markers in  the  text  called  "marks".
       Marks are used to keep track of various interesting positions in the text as it is edited.
       See MARKS below for more details.

       The third form of annotation allows arbitrary windows to be embedded  in  a  text  widget.
       See EMBEDDED WINDOWS below for more details.

       The  fourth  form  of  annotation  allows  Tk images to be embedded in a text widget.  See
       EMBEDDED IMAGES below for more details.

       The text widget also has a built-in undo/redo mechanism.  See THE UNDO MECHANISM below for │
       more details.

INDICES

       Many  of the widget commands for texts take one or more indices as arguments.  An index is
       a string used to indicate a particular place within a text, such  as  a  place  to  insert
       characters or one endpoint of a range of characters to delete.  Indices have the syntax
              base modifier modifier modifier ...
       Where  base  gives  a  starting point and the modifiers adjust the index from the starting
       point (e.g. move forward or backward one character).  Every index must contain a base, but
       the modifiers are optional.

       The base for an index must have one of the following forms:

       line.char   Indicates  char'th  character  on  line  line.   Lines are numbered from 1 for
                   consistency with other UNIX programs that use this numbering scheme.  Within a
                   line,  characters  are  numbered from 0.  If char is end then it refers to the
                   newline character that ends the line.

       @x,y        Indicates the character that covers the pixel whose x and y coordinates within
                   the text's window are x and y.

       end         Indicates the end of the text (the character just after the last newline).

       mark        Indicates the character just after the mark whose name is mark.

       tag.first   Indicates the first character in the text that has been tagged with tag.  This
                   form generates an error if no characters are currently tagged with tag.

       tag.last    Indicates the character just after the last one in  the  text  that  has  been
                   tagged  with tag.  This form generates an error if no characters are currently
                   tagged with tag.

       pathName    Indicates the position of the embedded window whose name  is  pathName.   This
                   form generates an error if there is no embedded window by the given name.

       imageName   Indicates  the  position  of the embedded image whose name is imageName.  This
                   form generates an error if there is no embedded image by the given name.

       If the base could match more than one of the above forms, such as  a  mark  and  imageName
       both  having the same value, then the form earlier in the above list takes precedence.  If
       modifiers follow the base index, each one of them must have one of the forms listed below.
       Keywords  such  as  chars  and  wordend  may be abbreviated as long as the abbreviation is
       unambiguous.

       + count chars
              Adjust the index forward by count characters, moving to later lines in the text  if
              necessary.   If there are fewer than count characters in the text after the current
              index, then set the index to the last character in the text.  Spaces on either side
              of count are optional.

       - count chars
              Adjust  the index backward by count characters, moving to earlier lines in the text
              if necessary.  If there are fewer than count characters  in  the  text  before  the
              current  index,  then  set the index to the first character in the text.  Spaces on
              either side of count are optional.

       + count lines
              Adjust the index forward by count lines,  retaining  the  same  character  position
              within the line.  If there are fewer than count lines after the line containing the
              current index, then set the index to refer to the same character  position  on  the
              last line of the text.  Then, if the line is not long enough to contain a character
              at the indicated character position, adjust the character position to refer to  the
              last  character  of  the  line  (the  newline).  Spaces on either side of count are
              optional.

       - count lines
              Adjust the index backward by count lines, retaining  the  same  character  position
              within  the  line.   If there are fewer than count lines before the line containing
              the current index, then set the index to refer to the same  character  position  on
              the  first  line  of  the  text.  Then, if the line is not long enough to contain a
              character at the indicated character position, adjust  the  character  position  to
              refer  to  the  last character of the line (the newline).  Spaces on either side of
              count are optional.

       linestart
              Adjust the index to refer to the first character on the line.

       lineend
              Adjust the index to refer to the last character on the line (the newline).

       wordstart
              Adjust the index to refer to the first character of the word containing the current
              index.   A  word  consists  of  any number of adjacent characters that are letters,
              digits, or underscores, or a single character that is not one of these.

       wordend
              Adjust the index to refer to the character just after the  last  one  of  the  word
              containing the current index.  If the current index refers to the last character of
              the text then it is not modified.

       If more than one modifier is present then they are applied in  left-to-right  order.   For
       example,  the index ``end - 1 chars'' refers to the next-to-last character in the text and
       ``insert wordstart - 1 c'' refers to the character just before the first one in  the  word
       containing  the  insertion cursor.  Modifiers are applied one by one in this left to right
       order, and after each step the resulting index is constrained to be a valid index  in  the
       text widget.  So, for example, the index ``1.0 -1c +1c'' refers to the index ``2.0''.

TAGS

       The  first form of annotation in text widgets is a tag.  A tag is a textual string that is
       associated with some of the characters in a text.  Tags may contain arbitrary  characters,
       but  it  is  probably  best  to  avoid  using the characters `` '' (space), +, or -: these
       characters have special meaning in indices, so tags  containing  them  can't  be  used  as
       indices.   There may be any number of tags associated with characters in a text.  Each tag
       may refer to a single character, a range of characters, or several ranges  of  characters.
       An individual character may have any number of tags associated with it.

       A priority order is defined among tags, and this order is used in implementing some of the
       tag-related functions described below.  When a tag is  defined  (by  associating  it  with
       characters  or  setting  its  display  options  or  binding commands to it), it is given a
       priority higher than any existing tag.  The priority order of tags may be redefined  using
       the ``pathName tag raise'' and ``pathName tag lower'' widget commands.

       Tags  serve  three  purposes  in text widgets.  First, they control the way information is
       displayed on the screen.  By default,  characters  are  displayed  as  determined  by  the
       background,  font,  and  foreground options for the text widget.  However, display options
       may be associated with  individual  tags  using  the  ``pathName  tag  configure''  widget
       command.  If a character has been tagged, then the display options associated with the tag
       override the default display style.  The following options  are  currently  supported  for
       tags:

       -background color
              Color specifies the background color to use for characters associated with the tag.
              It may have any of the forms accepted by Tk_GetColor.

       -bgstipple bitmap
              Bitmap specifies a bitmap that is used as a stipple pattern for the background.  It
              may  have  any  of  the  forms  accepted  by  Tk_GetBitmap.   If bitmap hasn't been
              specified, or if it is specified as an empty string, then a solid fill will be used
              for the background.

       -borderwidth pixels
              Pixels  specifies  the width of a 3-D border to draw around the background.  It may
              have any of the forms accepted by Tk_GetPixels.  This option is used in conjunction
              with  the -relief option to give a 3-D appearance to the background for characters;
              it is ignored unless the -background option has been set for the tag.

       -elide boolean
              Elide specifies whether the data should be elided.  Elided data  is  not  displayed
              and takes no space on screen, but further on behaves just as normal data.

       -fgstipple bitmap
              Bitmap  specifies  a bitmap that is used as a stipple pattern when drawing text and
              other foreground information such as underlines.  It may  have  any  of  the  forms
              accepted  by  Tk_GetBitmap.  If bitmap hasn't been specified, or if it is specified
              as an empty string, then a solid fill will be used.

       -font fontName
              FontName is the name of a font to use for drawing characters.  It may have  any  of
              the forms accepted by Tk_GetFont.

       -foreground color
              Color specifies the color to use when drawing text and other foreground information
              such as underlines.  It may have any of the forms accepted by Tk_GetColor.

       -justify justify
              If the first character of a display line has a tag for which this option  has  been
              specified,  then  justify  determines  how  to justify the line.  It must be one of
              left, right, or center.  If a line wraps, then the justification for each  line  on
              the display is determined by the first character of that display line.

       -lmargin1 pixels
              If  the  first  character  of  a text line has a tag for which this option has been
              specified, then pixels specifies how much the line should be indented from the left
              edge  of  the  window.   Pixels  may  have  any  of  the  standard forms for screen
              distances.  If a line of text wraps, this option only applies to the first line  on
              the display;  the -lmargin2 option controls the indentation for subsequent lines.

       -lmargin2 pixels
              If  the  first character of a display line has a tag for which this option has been
              specified, and if the display line is not the first for its text  line  (i.e.,  the
              text  line has wrapped), then pixels specifies how much the line should be indented
              from the left edge of the window.  Pixels may have any of the  standard  forms  for
              screen  distances.   This option is only used when wrapping is enabled, and it only
              applies to the second and later display lines for a text line.

       -offset pixels
              Pixels specifies an amount by which the text's baseline should be offset vertically
              from  the  baseline of the overall line, in pixels.  For example, a positive offset
              can be used for superscripts and a negative offset  can  be  used  for  subscripts.
              Pixels may have any of the standard forms for screen distances.

       -overstrike boolean
              Specifies  whether  or  not  to  draw  a  horizontal  rule  through  the  middle of
              characters.  Boolean may have any of the forms accepted by Tcl_GetBoolean.

       -relief relief
              Relief specifies the 3-D relief to use for drawing backgrounds, in any of the forms
              accepted by Tk_GetRelief.  This option is used in conjunction with the -borderwidth
              option to give a 3-D appearance to the background for  characters;  it  is  ignored
              unless the -background option has been set for the tag.

       -rmargin pixels
              If  the  first character of a display line has a tag for which this option has been
              specified, then pixels specifies how wide a margin to leave between the end of  the
              line  and  the right edge of the window.  Pixels may have any of the standard forms
              for screen distances.  This option is only used when wrapping  is  enabled.   If  a
              text line wraps, the right margin for each line on the display is determined by the
              first character of that display line.

       -spacing1 pixels
              Pixels specifies how much additional space should be left  above  each  text  line,
              using any of the standard forms for screen distances.  If a line wraps, this option
              only applies to the first line on the display.

       -spacing2 pixels
              For lines that wrap, this option specifies  how  much  additional  space  to  leave
              between  the  display  lines  for  a  single text line.  Pixels may have any of the
              standard forms for screen distances.

       -spacing3 pixels
              Pixels specifies how much additional space should be left  below  each  text  line,
              using any of the standard forms for screen distances.  If a line wraps, this option
              only applies to the last line on the display.

       -tabs tabList
              TabList specifies a set of tab stops in the same form as for the -tabs  option  for
              the  text  widget.  This option only applies to a display line if it applies to the
              first character on that display line.  If this option  is  specified  as  an  empty
              string,  it  cancels  the option, leaving it unspecified for the tag (the default).
              If the option is specified as a non-empty string that is an  empty  list,  such  as
              -tags { },  then  it  requests  default  8-character tabs as described for the tags
              widget option.

       -underline boolean
              Boolean specifies whether or not to draw an underline  underneath  characters.   It
              may have any of the forms accepted by Tcl_GetBoolean.

       -wrap mode
              Mode  specifies  how to handle lines that are wider than the text's window.  It has
              the same legal values as the -wrap option for the  text  widget:   none,  char,  or
              word.   If this tag option is specified, it overrides the -wrap option for the text
              widget.

       If a character has several tags associated with it, and if their display options conflict,
       then  the  options  of  the highest priority tag are used.  If a particular display option
       hasn't been specified for a particular tag, or if it is specified as an empty string, then
       that option will never be used;  the next-highest-priority tag's option will used instead.
       If no tag specifies a particular display option, then the default  style  for  the  widget
       will be used.

       The  second  purpose for tags is event bindings.  You can associate bindings with a tag in
       much the same way you can associate bindings with a widget class:  whenever  particular  X
       events  occur on characters with the given tag, a given Tcl command will be executed.  Tag
       bindings can be used to give behaviors to ranges of characters; among other  things,  this
       allows hypertext-like features to be implemented.  For details, see the description of the
       tag bind widget command below.

       The third use for tags is in managing the selection.  See THE SELECTION below.

MARKS

       The second form of annotation in text widgets is a mark.  Marks are used  for  remembering
       particular  places  in  a text.  They are something like tags, in that they have names and
       they refer to places in the file, but a mark isn't associated with particular  characters.
       Instead, a mark is associated with the gap between two characters.  Only a single position
       may be associated with a mark at any given time.  If the  characters  around  a  mark  are
       deleted  the  mark  will  still  remain;   it  will just have new neighbor characters.  In
       contrast, if the characters containing a tag are deleted then the tag will no longer  have
       an  association with characters in the file.  Marks may be manipulated with the ``pathName
       mark'' widget command, and their current locations may be determined  by  using  the  mark
       name as an index in widget commands.

       Each  mark  also  has  a "gravity", which is either left or right.  The gravity for a mark
       specifies what happens to the mark when text is inserted at the point of the mark.   If  a
       mark has left gravity, then the mark is treated as if it were attached to the character on
       its left, so the mark will remain to the left of any text inserted at the  mark  position.
       If  the  mark has right gravity, new text inserted at the mark position will appear to the
       left of the mark (so that the mark remains rightmost).  The gravity for a mark defaults to
       right.

       The  name  space for marks is different from that for tags:  the same name may be used for
       both a mark and a tag, but they will refer to different things.

       Two marks have special significance.  First,  the  mark  insert  is  associated  with  the
       insertion cursor, as described under THE INSERTION CURSOR below.  Second, the mark current
       is associated with the character closest to the mouse and  is  adjusted  automatically  to
       track  the  mouse  position  and  any  changes  to  the text in the widget (one exception:
       current is not updated in response to mouse motions if a mouse button is down;  the update
       will  be  deferred  until all mouse buttons have been released).  Neither of these special
       marks may be deleted.

EMBEDDED WINDOWS

       The third form of annotation in text widgets is an embedded window.  Each embedded  window
       annotation  causes a window to be displayed at a particular point in  the text.  There may
       be any number of embedded windows in a text widget, and any  widget  may  be  used  as  an
       embedded  window  (subject  to  the usual rules for geometry management, which require the
       text window to be the parent of the embedded window or a descendant of its  parent).   The
       embedded  window's  position  on  the  screen  will  be updated as the text is modified or
       scrolled, and it will be mapped and unmapped as it moves into and out of the visible  area
       of the text widget.  Each embedded window occupies one character's worth of index space in
       the text widget, and it may be referred to either by the name of its embedded window or by
       its  position  in  the widget's index space.  If the range of text containing the embedded
       window is deleted then the window is destroyed.

       When an embedded window is added to a text widget with the window create  widget  command,
       several  configuration  options may be associated with it.  These options may be  modified
       later with the window configure widget  command.   The  following  options  are  currently
       supported:

       -align where
              If  the  window  is  not  as tall as the line in which it is displayed, this option
              determines where the window is displayed in the line.  Where must have one  of  the
              values  top  (align the top of the window with the top of the line), center (center
              the window within the range of the line), bottom (align the bottom  of  the  window
              with  the  bottom  of the line's area), or baseline (align the bottom of the window
              with the baseline of the line).

       -create script
              Specifies a Tcl script  that  may  be  evaluated  to  create  the  window  for  the
              annotation.  If no -window option has been specified for the annotation this script
              will be evaluated when the annotation is about  to  be  displayed  on  the  screen.
              Script  must  create a window for the annotation and return the name of that window
              as its result.  If the annotation's window should ever be deleted, script  will  be
              evaluated again the next time the annotation is displayed.

       -padx pixels
              Pixels  specifies  the  amount of extra space to leave on each side of the embedded
              window.  It may have any of the usual forms defined for a screen distance.

       -pady pixels
              Pixels specifies the amount of extra space to leave on the top and on the bottom of
              the  embedded  window.   It  may  have  any of the usual forms defined for a screen
              distance.

       -stretch boolean
              If the requested height of the embedded window is less than the height of the  line
              in  which  it  is  displayed, this option can be used to specify whether the window
              should be stretched vertically to fill its line.  If  the  -pady  option  has  been
              specified  as  well, then the requested padding will be retained even if the window
              is stretched.

       -window pathName
              Specifies the name of a window to display in the annotation.

EMBEDDED IMAGES

       The final form of annotation in text widgets is an embedded image.   Each  embedded  image
       annotation  causes an image to be displayed at a particular point in  the text.  There may
       be any number of embedded images in a text widget, and a particular image may be  embedded
       in  multiple  places in the same text widget.  The embedded image's position on the screen
       will be updated as the text is modified or scrolled.  Each  embedded  image  occupies  one
       character's  worth  of index space in the text widget, and it may be referred to either by
       its position in the widget's index space, or the name it is assigned  when  the  image  is
       inserted  into  the  text  widget  with image create.  If the range of text containing the
       embedded image is deleted then that copy of the image is removed from the screen.

       When an embedded image is added to a text widget with the image create widget  command,  a
       name  unique  to  this  instance  of the image is returned.  This name may then be used to
       refer to this image instance.  The name is taken to be  the  value  of  the  -name  option
       (described  below).  If the -name option is not provided, the -image name is used instead.
       If the imageName is already in use in the text widget, then #nn is added to the end of the
       imageName,  where nn is an arbitrary integer.  This insures the imageName is unique.  Once
       this name is assigned to this instance of the image, it does not change, even  though  the
       -image or -name values can be changed with image configure.

       When  an  embedded  image  is added to a text widget with the image create widget command,
       several configuration options may be associated with it.  These options  may  be  modified
       later  with  the  image  configure  widget  command.   The following options are currently
       supported:

       -align where
              If the image is not as tall as the line in  which  it  is  displayed,  this  option
              determines  where  the  image is displayed in the line.  Where must have one of the
              values top (align the top of the image with the top of the  line),  center  (center
              the image within the range of the line), bottom (align the bottom of the image with
              the bottom of the line's area), or baseline (align the bottom of the image with the
              baseline of the line).

       -image image
              Specifies the name of the Tk image to display in the annotation.  If image is not a
              valid Tk image, then an error is returned.

       -name ImageName
              Specifies the name by which this image instance  may  be  referenced  in  the  text
              widget.  If  ImageName  is  not  supplied,  then  the  name of the Tk image is used
              instead.  If the imageName is already in use, #nn is appended to  the  end  of  the
              name as described above.

       -padx pixels
              Pixels  specifies  the  amount of extra space to leave on each side of the embedded
              image.  It may have any of the usual forms defined for a screen distance.

       -pady pixels
              Pixels specifies the amount of extra space to leave on the top and on the bottom of
              the  embedded  image.   It  may  have  any  of the usual forms defined for a screen
              distance.

THE SELECTION

       Selection support is implemented via tags.  If the exportSelection  option  for  the  text
       widget is true then the sel tag will be associated with the selection:

       [1]    Whenever characters are tagged with sel the text widget will claim ownership of the
              selection.

       [2]    Attempts to retrieve the selection will be serviced by the text  widget,  returning
              all the characters with the sel tag.

       [3]    If the selection is claimed away by another application or by another window within
              this application, then the sel tag will be removed from all characters in the text.

       [4]    Whenever the sel tag range changes a virtual event <<Selection>> is generated.

       The sel tag is automatically defined when a text widget is created,  and  it  may  not  be
       deleted   with   the   ``pathName   tag   delete''   widget   command.   Furthermore,  the
       selectBackground, selectBorderWidth, and selectForeground options for the text widget  are
       tied  to  the -background, -borderwidth, and -foreground options for the sel tag:  changes
       in either will automatically be reflected in the other.

THE INSERTION CURSOR

       The  mark  named  insert  has  special  significance  in  text  widgets.   It  is  defined
       automatically  when  a  text widget is created and it may not be unset with the ``pathName
       mark unset'' widget command.  The insert mark represents the  position  of  the  insertion
       cursor,  and  the  insertion cursor will automatically be drawn at this point whenever the
       text widget has the input focus.

THE MODIFIED FLAG

       The text widget can keep track of changes to the content of the widget  by  means  of  the
       modified flag. Inserting or deleting text will set this flag. The flag can be queried, set
       and cleared programmatically as well. Whenever  the  flag  changes  state  a  <<Modified>>
       virtual event is generated. See the edit modified widget command for more details.

THE UNDO MECHANISM

       The  text widget has an unlimited undo and redo mechanism (when the -undo widget option is │
       true) which records every insert and delete action on a stack.                             │

       Boundaries (called "separators") are inserted between edit actions.  The purpose of  these │
       separators  is to group inserts, deletes and replaces into one compound edit action.  When │
       undoing a change everything between two separators will be undone.  The undone changes are │
       then  moved to the redo stack, so that an undone edit can be redone again.  The redo stack │
       is cleared whenever new edit actions are recorded on the undo stack.  The  undo  and  redo │
       stacks can be cleared to keep their depth under control.                                   │

       Separators are inserted automatically when the -autoseparators widget option is true.  You │
       can insert separators programmatically as well.  If a separator is already present at  the │
       top  of  the  undo stack no other will be inserted.  That means that two separators on the │
       undo stack are always separated by at least one insert or delete action.                   │

       The undo mechanism is also linked to the  modified  flag.   This  means  that  undoing  or │
       redoing  changes  can  take  a  modified  text widget back to the unmodified state or vice │
       versa.  The modified flag will be  set  automatically  to  the  appropriate  state.   This │
       automatic  coupling  does  not work when the modified flag has been set by the user, until │
       the flag has been reset again.                                                             │

       See below for the edit widget command that controls the undo mechanism.

WIDGET COMMAND

       The text command creates a new Tcl command whose name is the same as the path name of  the
       text's  window.   This command may be used to invoke various operations on the widget.  It
       has the following general form:
              pathName option ?arg arg ...?
       PathName is the name of the command, which is the same as the  text  widget's  path  name.
       Option  and  the args determine the exact behavior of the command.  The following commands
       are possible for text widgets:

       pathName bbox index
              Returns a list of four elements describing the screen area of the  character  given
              by  index.   The first two elements of the list give the x and y coordinates of the
              upper-left corner of the area occupied by the character, and the last two  elements
              give  the width and height of the area.  If the character is only partially visible
              on the screen, then the return value  reflects  just  the  visible  part.   If  the
              character is not visible on the screen then the return value is an empty list.

       pathName cget option
              Returns  the current value of the configuration option given by option.  Option may
              have any of the values accepted by the text command.

       pathName compare index1 op index2
              Compares the indices given  by  index1  and  index2  according  to  the  relational
              operator  given  by  op, and returns 1 if the relationship is satisfied and 0 if it
              isn't.  Op must be one of the operators <, <=, ==, >=, >, or !=.  If op is ==  then
              1  is returned if the two indices refer to the same character, if op is < then 1 is
              returned if index1 refers to an earlier character in the text than index2,  and  so
              on.

       pathName configure ?option? ?value option value ...?
              Query  or  modify  the  configuration  options  of  the  widget.   If  no option is
              specified, returns a list describing all of the available options for pathName (see
              Tk_ConfigureInfo  for  information  on  the  format  of  this  list).  If option is
              specified with no value, then the command returns a list describing the  one  named
              option  (this  list  will  be  identical  to the corresponding sublist of the value
              returned if no option is  specified).   If  one  or  more  option-value  pairs  are
              specified,  then  the command modifies the given widget option(s) to have the given
              value(s);  in this case the command returns an empty string.  Option may  have  any
              of the values accepted by the text command.

       pathName debug ?boolean?
              If boolean is specified, then it must have one of the true or false values accepted
              by Tcl_GetBoolean.  If the value is a true one  then  internal  consistency  checks
              will  be turned on in the B-tree code associated with text widgets.  If boolean has
              a false value then the debugging checks will be turned off.   In  either  case  the
              command  returns  an  empty  string.   If boolean is not specified then the command
              returns on or off to indicate whether or not debugging is turned on.   There  is  a
              single debugging switch shared by all text widgets:  turning debugging on or off in
              any widget turns it on or off for all widgets.  For widgets with large  amounts  of
              text, the consistency checks may cause a noticeable slow-down.

       When  debugging  is  turned  on,  the  drawing  routines of the text widget set the global │
       variables tk_textRedraw and tk_textRelayout to the lists of indices that are redrawn.  The │
       values of these variables are tested by Tk's test suite.

       pathName delete index1 ?index2 ...?
              Delete  a  range  of  characters  from  the  text.   If  both index1 and index2 are
              specified, then delete all the characters starting with the one given by index1 and
              stopping  just  before  index2  (i.e.  the character at index2 is not deleted).  If
              index2 doesn't specify a position later in the text than index1 then no  characters
              are  deleted.   If  index2  isn't  specified then the single character at index1 is
              deleted.  It is not allowable to delete characters in a way that  would  leave  the
              text without a newline as the last character.  The command returns an empty string. │
              If more indices are given, multiple ranges of text will be  deleted.   All  indices │
              are  first checked for validity before any deletions are made.  They are sorted and │
              the text is removed from the last range to the first range to deleted text does not │
              cause  an  undesired index shifting side-effects.  If multiple ranges with the same │
              start index are given, then the longest range is used.  If overlapping  ranges  are │
              given,  then  they  will  be  merged  into spans that do not cause deletion of text │
              outside the given ranges due to text shifted during deletion.

       pathName dlineinfo index
              Returns a list with five elements describing the area occupied by the display  line
              containing  index.  The first two elements of the list give the x and y coordinates
              of the upper-left corner of the area occupied by the line,  the  third  and  fourth
              elements  give  the  width  and height of the area, and the fifth element gives the
              position of the baseline for the line, measured down from the top of the area.  All
              of  this  information  is measured in pixels.  If the current wrap mode is none and
              the line extends beyond the boundaries of the window, the  area  returned  reflects
              the entire area of the line, including the portions that are out of the window.  If
              the line is shorter than the full width  of  the  window  then  the  area  returned
              reflects  just  the portion of the line that is occupied by characters and embedded
              windows.  If the display line containing index is not visible on  the  screen  then
              the return value is an empty list.

       pathName dump ?switches? index1 ?index2?
              Return the contents of the text widget from index1 up to, but not including index2,
              including the text and information about marks, tags,  and  embedded  windows.   If
              index2  is  not  specified,  then  it  defaults  to one character past index1.  The
              information is returned in the following format:

              key1 value1 index1 key2 value2 index2 ...

              The possible key values are text, mark, tagon,  tagoff,  image,  and  window.   The
              corresponding  value  is the text, mark name, tag name, image name, or window name.
              The index information is the index of the start of the text, mark, tag  transition,
              image  or window.  One or more of the following switches (or abbreviations thereof)
              may be specified to control the dump:

              -all   Return information  about  all  elements:  text,  marks,  tags,  images  and
                     windows.  This is the default.

              -command command
                     Instead  of  returning  the information as the result of the dump operation,
                     invoke the command on each element of the text widget within the range.  The
                     command  has three arguments appended to it before it is evaluated: the key,
                     value, and index.

              -image Include information about images in the dump results.

              -mark  Include information about marks in the dump results.

              -tag   Include  information  about  tag  transitions  in  the  dump  results.   Tag
                     information is returned as tagon and tagoff elements that indicate the begin
                     and end of each range of each tag, respectively.

              -text  Include information about text in the dump results.  The value is  the  text
                     up  to  the  next  element  or the end of range indicated by index2.  A text
                     element does not span newlines.  A multi-line block of text that contains no
                     marks or tag transitions will still be dumped as a set of text segments that
                     each end with a newline.  The newline is part of the value.

              -window
                     Include information about embedded windows in the dump results.   The  value
                     of  a window is its Tk pathname, unless the window has not been created yet.
                     (It must have a create script.)  In this case an empty string  is  returned,
                     and you must query the window by its index position to get more information.

       pathName edit option ?arg arg ...?
              This command controls the undo mechanism and the modified flag.  The exact behavior │
              of the command depends on the option argument that follows the edit argument.   The │
              following forms of the command are currently supported:                             │

              pathName edit modified ?boolean?                                                    │
                     If  boolean  is  not specified, returns the modified flag of the widget. The │
                     insert, delete, edit undo and edit redo commands or  the  user  can  set  or │
                     clear the modified flag.  If boolean is specified, sets the modified flag of │
                     the widget to boolean.                                                       │

              pathName edit redo                                                                  │
                     When the -undo option is true, reapplies the last undone edits  provided  no │
                     other  edits were done since then. Generates an error when the redo stack is │
                     empty.  Does nothing when the -undo option is false.                         │

              pathName edit reset                                                                 │
                     Clears the undo and redo stacks.                                             │

              pathName edit separator                                                             │
                     Inserts a separator (boundary) on the undo  stack.  Does  nothing  when  the │
                     -undo option is false.                                                       │

              pathName edit undo                                                                  │
                     Undoes  the  last edit action when the -undo option is true.  An edit action │
                     is defined as all the insert and delete commands that are  recorded  on  the │
                     undo stack in between two separators. Generates an error when the undo stack │
                     is empty.  Does nothing when the -undo option is false.                      │

       pathName get index1 ?index2 ...?
              Return a range of characters from the text.  The  return  value  will  be  all  the
              characters  in the text starting with the one whose index is index1 and ending just
              before the one whose  index  is  index2  (the  character  at  index2  will  not  be
              returned).   If  index2 is omitted then the single character at index1 is returned.
              If there are no characters in the specified range (e.g. index1 is past the  end  of
              the  file  or  index2  is  less  than  or  equal to index1) then an empty string is
              returned.  If the specified range contains embedded windows, no  information  about
              them  is  included  in  the  returned  string.   If multiple index pairs are given, │
              multiple ranges of text will be returned in a list.  Invalid  ranges  will  not  be │
              represented  with  empty strings in the list.  The ranges are returned in the order │
              passed to get.

       pathName image option ?arg arg ...?
              This command is used to manipulate embedded images.  The behavior  of  the  command
              depends  on the option argument that follows the tag argument.  The following forms
              of the command are currently supported:

              pathName image cget index option
                     Returns the value of a configuration option for an  embedded  image.   Index
                     identifies   the   embedded   image,   and  option  specifies  a  particular
                     configuration option, which must be one of the ones listed  in  the  section
                     EMBEDDED IMAGES.

              pathName image configure index ?option value ...?
                     Query  or  modify  the  configuration  options for an embedded image.  If no
                     option is specified, returns a list describing all of the available  options
                     for the embedded image at index (see Tk_ConfigureInfo for information on the
                     format of this list).  If option  is  specified  with  no  value,  then  the
                     command  returns  a  list describing the one named option (this list will be
                     identical to the corresponding sublist of the value returned if no option is
                     specified).   If  one  or  more  option-value  pairs are specified, then the
                     command modifies the given option(s) to have the given  value(s);   in  this
                     case  the  command  returns  an  empty  string.   See  EMBEDDED  IMAGES  for
                     information on the options that are supported.

              pathName image create index ?option value ...?
                     This command creates a new image annotation, which will appear in  the  text
                     at  the  position  given  by index.  Any number of option-value pairs may be
                     specified to configure the annotation.  Returns a unique identifier that may
                     be  used  as  an  index  to  refer  to  this image.  See EMBEDDED IMAGES for
                     information on the options that are supported,  and  a  description  of  the
                     identifier returned.

              pathName image names
                     Returns a list whose elements are the names of all image instances currently
                     embedded in window.

       pathName index index
              Returns the position corresponding to index in the form line.char where line is the
              line  number  and  char  is  the character number.  Index may have any of the forms
              described under INDICES above.

       pathName insert index chars ?tagList chars tagList ...?
              Inserts all of the chars arguments just before the character at  index.   If  index
              refers  to  the end of the text (the character after the last newline) then the new
              text is inserted just before the last newline instead.  If there is a single  chars
              argument  and  no tagList, then the new text will receive any tags that are present
              on both the character before and the character after the insertion point; if a  tag
              is  present  on only one of these characters then it will not be applied to the new
              text.  If tagList is specified then it consists of a list of tag  names;   the  new
              characters  will  receive all of the tags in this list and no others, regardless of
              the tags present around the insertion point.  If  multiple  chars-tagList  argument
              pairs  are  present,  they  produce  the same effect as if a separate insert widget
              command had been issued for each pair, in order.  The last tagList argument may  be
              omitted.

       pathName mark option ?arg arg ...?
              This  command  is  used  to  manipulate  marks.   The exact behavior of the command
              depends on the option argument that follows the mark argument.  The following forms
              of the command are currently supported:

              pathName mark gravity markName ?direction?
                     If  direction  is  not specified, returns left or right to indicate which of
                     its adjacent characters markName is attached to.  If direction is specified,
                     it must be left or right; the gravity of markName is set to the given value.

              pathName mark names
                     Returns  a  list  whose  elements  are  the  names of all the marks that are
                     currently set.

              pathName mark next index
                     Returns the name of the next mark at or after index.  If index is  specified
                     in  numerical  form, then the search for the next mark begins at that index.
                     If index is the name of a mark, then the search for  the  next  mark  begins
                     immediately  after  that  mark.   This  can  still return a mark at the same
                     position if there are multiple marks at the  same  index.   These  semantics
                     mean  that the mark next operation can be used to step through all the marks
                     in a text widget in the same order as the mark information returned  by  the
                     dump  operation.   If  a mark has been set to the special end index, then it
                     appears to be after end with respect to the mark next operation.   An  empty
                     string is returned if there are no marks after index.

              pathName mark previous index
                     Returns  the  name of the mark at or before index.  If index is specified in
                     numerical form, then the search  for  the  previous  mark  begins  with  the
                     character  just before that index.  If index is the name of a mark, then the
                     search for the next mark begins immediately  before  that  mark.   This  can
                     still  return a mark at the same position if there are multiple marks at the
                     same index.  These semantics mean that the mark previous  operation  can  be
                     used  to step through all the marks in a text widget in the reverse order as
                     the mark information returned by the dump operation.   An  empty  string  is
                     returned if there are no marks before index.

              pathName mark set markName index
                     Sets  the  mark  named  markName  to a position just before the character at
                     index.  If markName already exists, it is moved from its old position; if it
                     doesn't exist, a new mark is created.  This command returns an empty string.

              pathName mark unset markName ?markName markName ...?
                     Remove  the  mark  corresponding  to  each  of  the markName arguments.  The
                     removed marks will not be usable in indices and  will  not  be  returned  by
                     future  calls  to  ``pathName  mark  names''.  This command returns an empty
                     string.

       pathName scan option args
              This command is used to implement scanning on texts.  It has two  forms,  depending
              on option:

              pathName scan mark x y
                     Records  x  and  y  and  the  current  view  in  the text window, for use in
                     conjunction with later scan dragto  commands.   Typically  this  command  is
                     associated  with  a  mouse  button press in the widget.  It returns an empty
                     string.

              pathName scan dragto x y
                     This command computes the difference between its x and y arguments and the x
                     and  y  arguments  to  the  last  scan mark command for the widget.  It then
                     adjusts the view by 10 times the difference in coordinates.  This command is
                     typically  associated with mouse motion events in the widget, to produce the
                     effect of dragging the text at high speed through the  window.   The  return
                     value is an empty string.

       pathName search ?switches? pattern index ?stopIndex?
              Searches  the  text  in  pathName  starting at index for a range of characters that
              matches pattern.  If a match is found, the index of  the  first  character  in  the
              match  is  returned as result;  otherwise an empty string is returned.  One or more
              of the following switches (or abbreviations thereof) may be  specified  to  control
              the search:

              -forwards
                     The search will proceed forward through the text, finding the first matching
                     range starting at or after  the  position  given  by  index.   This  is  the
                     default.

              -backwards
                     The  search  will  proceed  backward  through the text, finding the matching
                     range closest to index whose first character is before index.

              -exact Use exact matching:  the characters in the matching range must be  identical
                     to those in pattern.  This is the default.

              -regexp
                     Treat  pattern  as  a regular expression and match it against the text using
                     the rules for regular expressions (see the regexp command for details).

              -nocase
                     Ignore case differences between the pattern and the text.

              -count varName
                     The argument following -count gives the name of a variable; if  a  match  is
                     found,  the  number  of  index  positions  between  beginning and end of the
                     matching range will be stored in the variable.  If  there  are  no  embedded
                     images  or windows in the matching range (and there are no elided characters
                     if -elide is not given), this is equivalent  to  the  number  of  characters
                     matched.  In either case, the range matchIdx to matchIdx + $count chars will
                     return the entire matched text.

              -elide Find elided (hidden) text  as  well.  By  default  only  displayed  text  is
                     searched.

              --     This switch has no effect except to terminate the list of switches: the next
                     argument will be treated as pattern even if it starts with -.

              The matching range must be entirely within a single  line  of  text.   For  regular
              expression  matching  the  newlines  are  removed from the ends of the lines before
              matching:  use the $ feature in regular expressions to match the  end  of  a  line.
              For  exact  matching  the  newlines  are  retained.  If stopIndex is specified, the
              search stops at that index: for forward searches, no match at  or  after  stopIndex
              will  be  considered;   for  backward  searches,  no match earlier in the text than
              stopIndex will be considered.  If stopIndex is omitted, the  entire  text  will  be
              searched: when the beginning or end of the text is reached, the search continues at
              the other end until the starting  location  is  reached  again;   if  stopIndex  is
              specified, no wrap-around will occur.

       pathName see index
              Adjusts  the  view in the window so that the character given by index is completely
              visible.  If index is already visible then the command does nothing.  If index is a
              short  distance out of view, the command adjusts the view just enough to make index
              visible at the edge of the window.  If index is far out of view, then  the  command
              centers index in the window.

       pathName tag option ?arg arg ...?
              This command is used to manipulate tags.  The exact behavior of the command depends
              on the option argument that follows the tag argument.  The following forms  of  the
              command are currently supported:

              pathName tag add tagName index1 ?index2 index1 index2 ...?
                     Associate  the  tag  tagName with all of the characters starting with index1
                     and ending just before index2 (the character at  index2  isn't  tagged).   A
                     single  command  may contain any number of index1-index2 pairs.  If the last
                     index2 is omitted then the single character at index1 is tagged.   If  there
                     are no characters in the specified range (e.g. index1 is past the end of the
                     file or index2 is less than or equal to index1)  then  the  command  has  no
                     effect.

              pathName tag bind tagName ?sequence? ?script?
                     This  command associates script with the tag given by tagName.  Whenever the
                     event sequence given by sequence occurs for a character that has been tagged
                     with tagName, the script will be invoked.  This widget command is similar to
                     the bind command except that it operates on characters in a text rather than
                     entire  widgets.   See  the  bind  manual  entry for complete details on the
                     syntax of sequence and the substitutions performed on script before invoking
                     it.  If all arguments are specified then a new binding is created, replacing
                     any existing binding for  the  same  sequence  and  tagName  (if  the  first
                     character of script is ``+'' then script augments an existing binding rather
                     than replacing it).  In this case the return value is an empty  string.   If
                     script  is  omitted  then  the  command  returns  the script associated with
                     tagName and sequence (an error occurs if there is no such binding).  If both
                     script  and  sequence are omitted then the command returns a list of all the
                     sequences for which bindings have been defined for tagName.

                     The only events for which bindings may be specified are those related to the │
                     mouse and keyboard (such as Enter, Leave, ButtonPress, Motion, and KeyPress) │
                     or virtual events.  Event bindings for a text widget use  the  current  mark │
                     described under MARKS above.  An Enter event triggers for a tag when the tag │
                     first becomes present on the current character, and a Leave  event  triggers │
                     for  a tag when it ceases to be present on the current character.  Enter and │
                     Leave events can happen either because the current mark moved or because the │
                     character  at  that  position changed.  Note that these events are different │
                     than Enter and Leave events for windows.   Mouse  and  keyboard  events  are │
                     directed to the current character.  If a virtual event is used in a binding, │
                     that binding can trigger  only  if  the  virtual  event  is  defined  by  an │
                     underlying mouse-related or keyboard-related event.

                     It is possible for the current character to have multiple tags, and for each
                     of them to have a binding  for  a  particular  event  sequence.   When  this
                     occurs,  one  binding is invoked for each tag, in order from lowest-priority
                     to highest priority.  If there are multiple matching bindings for  a  single
                     tag,  then the most specific binding is chosen (see the manual entry for the
                     bind command for details).   continue  and  break  commands  within  binding
                     scripts  are processed in the same way as for bindings created with the bind
                     command.

                     If bindings are created for the widget as a whole using  the  bind  command,
                     then those bindings will supplement the tag bindings.  The tag bindings will
                     be invoked first, followed by bindings for the window as a whole.

              pathName tag cget tagName option
                     This command returns the current value of the option named option associated
                     with  the  tag given by tagName.  Option may have any of the values accepted
                     by the tag configure widget command.

              pathName tag configure tagName ?option? ?value? ?option value ...?
                     This command is similar to the  configure  widget  command  except  that  it
                     modifies  options  associated  with  the  tag  given  by  tagName instead of
                     modifying options for the overall text widget.  If no option  is  specified,
                     the  command  returns  a  list  describing  all of the available options for
                     tagName (see Tk_ConfigureInfo for information on the format of  this  list).
                     If  option  is  specified  with  no  value,  then the command returns a list
                     describing the one  named  option  (this  list  will  be  identical  to  the
                     corresponding  sublist of the value returned if no option is specified).  If
                     one or more option-value pairs are specified, then the command modifies  the
                     given  option(s)  to  have  the  given value(s) in tagName; in this case the
                     command returns an empty string.  See TAGS above for details on the  options
                     available for tags.

              pathName tag delete tagName ?tagName ...?
                     Deletes  all tag information for each of the tagName arguments.  The command
                     removes the tags from all characters in the file and also deletes any  other
                     information   associated  with  the  tags,  such  as  bindings  and  display
                     information.  The command returns an empty string.

              pathName tag lower tagName ?belowThis?
                     Changes the priority of tag tagName so that it is  just  lower  in  priority
                     than  the  tag  whose  name  is  belowThis.   If  belowThis is omitted, then
                     tagName's priority is changed to make it lowest priority of all tags.

              pathName tag names ?index?
                     Returns a list whose elements are the names of all the tags that are  active
                     at  the  character  position  given by index.  If index is omitted, then the
                     return value will describe all of the tags that exist  for  the  text  (this
                     includes  all tags that have been named in a ``pathName tag'' widget command
                     but haven't been deleted by a ``pathName tag delete'' widget  command,  even
                     if  no  characters  are  currently  marked  with the tag).  The list will be
                     sorted in order from lowest priority to highest priority.

              pathName tag nextrange tagName index1 ?index2?
                     This command searches the text for a range of characters tagged with tagName
                     where  the  first character of the range is no earlier than the character at
                     index1 and no later than the character just before index2 (a range  starting
                     at  index2  will  not be considered).  If several matching ranges exist, the
                     first one is chosen.  The command's return value is a  list  containing  two
                     elements,  which  are  the index of the first character of the range and the
                     index of the character just after the last one in the range.  If no matching
                     range  is  found then the return value is an empty string.  If index2 is not
                     given then it defaults to the end of the text.

              pathName tag prevrange tagName index1 ?index2?
                     This command searches the text for a range of characters tagged with tagName
                     where the first character of the range is before the character at index1 and
                     no earlier than the character at index2 (a range starting at index2 will  be
                     considered).  If several matching ranges exist, the one closest to index1 is
                     chosen.  The command's return value is a list containing two elements, which
                     are  the  index  of  the  first  character of the range and the index of the
                     character just after the last one in the range.  If  no  matching  range  is
                     found then the return value is an empty string.  If index2 is not given then
                     it defaults to the beginning of the text.

              pathName tag raise tagName ?aboveThis?
                     Changes the priority of tag tagName so that it is just  higher  in  priority
                     than  the  tag  whose  name  is  aboveThis.   If  aboveThis is omitted, then
                     tagName's priority is changed to make it highest priority of all tags.

              pathName tag ranges tagName
                     Returns a list describing all of the ranges of text that  have  been  tagged
                     with  tagName.  The first two elements of the list describe the first tagged
                     range in the text, the next two elements describe the second range,  and  so
                     on.   The  first  element  of  each  pair  contains  the  index of the first
                     character of the range, and the second element  of  the  pair  contains  the
                     index  of  the character just after the last one in the range.  If there are
                     no characters tagged with tag then an empty string is returned.

              pathName tag remove tagName index1 ?index2 index1 index2 ...?
                     Remove the tag tagName from all of the characters  starting  at  index1  and
                     ending  just  before  index2  (the  character  at index2 isn't affected).  A
                     single command may contain any number of index1-index2 pairs.  If  the  last
                     index2  is  omitted then the single character at index1 is tagged.  If there
                     are no characters in the specified range (e.g. index1 is past the end of the
                     file  or  index2  is  less  than or equal to index1) then the command has no
                     effect.  This command returns an empty string.

       pathName window option ?arg arg ...?
              This command is used to manipulate embedded windows.  The behavior of  the  command
              depends  on the option argument that follows the tag argument.  The following forms
              of the command are currently supported:

              pathName window cget index option
                     Returns the value of a configuration option for an embedded  window.   Index
                     identifies   the   embedded   window,  and  option  specifies  a  particular
                     configuration option, which must be one of the ones listed  in  the  section
                     EMBEDDED WINDOWS.

              pathName window configure index ?option value ...?
                     Query  or  modify  the  configuration options for an embedded window.  If no
                     option is specified, returns a list describing all of the available  options
                     for  the  embedded  window at index (see Tk_ConfigureInfo for information on
                     the format of this list).  If option is specified with no  value,  then  the
                     command  returns  a  list describing the one named option (this list will be
                     identical to the corresponding sublist of the value returned if no option is
                     specified).   If  one  or  more  option-value  pairs are specified, then the
                     command modifies the given option(s) to have the given  value(s);   in  this
                     case  the  command  returns  an  empty  string.   See  EMBEDDED  WINDOWS for
                     information on the options that are supported.

              pathName window create index ?option value ...?
                     This command creates a new window annotation, which will appear in the  text
                     at  the  position  given  by index.  Any number of option-value pairs may be
                     specified to configure the annotation.  See EMBEDDED WINDOWS for information
                     on the options that are supported.  Returns an empty string.

              pathName window names
                     Returns  a  list  whose  elements  are  the  names  of all windows currently
                     embedded in window.

       pathName xview option args
              This command is used to query and change the horizontal position of the text in the
              widget's window.  It can take any of the following forms:

              pathName xview
                     Returns  a  list  containing  two elements.  Each element is a real fraction
                     between 0 and 1;  together they  describe  the  portion  of  the  document's
                     horizontal  span  that  is visible in the window.  For example, if the first
                     element is .2 and the second element is .6, 20% of the text is off-screen to
                     the  left,  the  middle 40% is visible in the window, and 40% of the text is
                     off-screen to the right.  The fractions refer only to  the  lines  that  are
                     actually  visible  in  the  window:  if the lines in the window are all very
                     short, so that they are entirely visible, the returned fractions will  be  0
                     and  1,  even  if there are other lines in the text that are much wider than
                     the window.  These  are  the  same  values  passed  to  scrollbars  via  the
                     -xscrollcommand option.

              pathName xview moveto fraction
                     Adjusts  the  view  in the window so that fraction of the horizontal span of
                     the text is off-screen to the left.  Fraction is a fraction between 0 and 1.

              pathName xview scroll number what
                     This command shifts the view in the window left or right according to number
                     and what.  Number must be an integer.  What must be either units or pages or
                     an abbreviation of one of these.  If what is units, the view adjusts left or
                     right  by  number  average-width  characters on the display;  if it is pages
                     then the view adjusts by number screenfuls.   If  number  is  negative  then
                     characters  farther  to  the  left  become  visible;  if it is positive then
                     characters farther to the right become visible.

       pathName yview ?args?
              This command is used to query and change the vertical position of the text  in  the
              widget's window.  It can take any of the following forms:

              pathName yview
                     Returns  a  list  containing  two elements, both of which are real fractions
                     between 0 and 1.   The  first  element  gives  the  position  of  the  first
                     character  in  the  top  line in the window, relative to the text as a whole
                     (0.5 means it is halfway through the text, for example).  The second element
                     gives  the  position  of the character just after the last one in the bottom
                     line of the window, relative to the text as a whole.   These  are  the  same
                     values passed to scrollbars via the -yscrollcommand option.

              pathName yview moveto fraction
                     Adjusts  the  view  in  the  window  so that the character given by fraction
                     appears on the top line of the window.  Fraction is a fraction between 0 and
                     1;   0  indicates  the  first  character  in  the  text,  0.33 indicates the
                     character one-third the way through the text, and so on.

              pathName yview scroll number what
                     This command adjust the view in the window up or down  according  to  number
                     and  what.   Number must be an integer.  What must be either units or pages.
                     If what is units, the view adjusts  up  or  down  by  number  lines  on  the
                     display;   if  it  is  pages then the view adjusts by number screenfuls.  If
                     number is negative then earlier positions in the text become visible;  if it
                     is positive then later positions in the text become visible.

              pathName yview ?-pickplace? index
                     Changes  the  view  in  the  widget's  window to make index visible.  If the
                     -pickplace option isn't specified then index will appear at the top  of  the
                     window.   If  -pickplace  is  specified  then the widget chooses where index
                     appears in the window:

                     [1]    If index is already visible somewhere in the window then the  command
                            does nothing.

                     [2]    If index is only a few lines off-screen above the window then it will
                            be positioned at the top of the window.

                     [3]    If index is only a few lines off-screen below the window then it will
                            be positioned at the bottom of the window.

                     [4]    Otherwise, index will be centered in the window.

                     The  -pickplace  option  has  been  obsoleted by the see widget command (see
                     handles both x- and y-motion to make a location visible, whereas  -pickplace
                     only handles motion in y).

              pathName yview number
                     This  command  makes  the first character on the line after the one given by
                     number visible at the top of the window.  Number must be an  integer.   This
                     command used to be used for scrolling, but now it is obsolete.

BINDINGS

       Tk  automatically  creates  class  bindings for texts that give them the following default
       behavior.  In  the  descriptions  below,  ``word''  is  dependent  on  the  value  of  the
       tcl_wordchars variable.  See tclvars(3tcl).

       [1]    Clicking  mouse  button  1 positions the insertion cursor just before the character
              underneath the mouse cursor, sets the input focus to this widget,  and  clears  any
              selection  in  the  widget.   Dragging  with mouse button 1 strokes out a selection
              between the insertion cursor and the character under the mouse.

       [2]    Double-clicking with mouse button 1 selects the word under the mouse and  positions
              the  insertion  cursor  at the end of the word.  Dragging after a double click will
              stroke out a selection consisting of whole words.

       [3]    Triple-clicking with mouse button 1 selects the line under the mouse and  positions
              the  insertion  cursor  at the end of the line.  Dragging after a triple click will
              stroke out a selection consisting of whole lines.

       [4]    The ends of the selection can be adjusted by dragging with mouse button 1 while the
              Shift  key  is down;  this will adjust the end of the selection that was nearest to
              the mouse cursor when button 1 was pressed.  If the button is double-clicked before
              dragging  then  the  selection  will be adjusted in units of whole words;  if it is
              triple-clicked then the selection will be adjusted in units of whole lines.

       [5]    Clicking mouse button 1 with the Control key down  will  reposition  the  insertion
              cursor without affecting the selection.

       [6]    If  any normal printing characters are typed, they are inserted at the point of the
              insertion cursor.

       [7]    The view in the widget can be adjusted by dragging with mouse button 2.   If  mouse
              button 2 is clicked without moving the mouse, the selection is copied into the text
              at the position of the mouse cursor.  The Insert key also  inserts  the  selection,
              but at the position of the insertion cursor.

       [8]    If the mouse is dragged out of the widget while button 1 is pressed, the entry will
              automatically scroll to make more text visible (if there is more text off-screen on
              the side where the mouse left the window).

       [9]    The  Left  and  Right  keys  move the insertion cursor one character to the left or
              right;  they also clear any selection in the text.  If Left or Right is typed  with
              the  Shift  key down, then the insertion cursor moves and the selection is extended
              to include the new character.  Control-Left and Control-Right  move  the  insertion
              cursor  by words, and Control-Shift-Left and Control-Shift-Right move the insertion
              cursor by words and also extend the selection.  Control-b and Control-f behave  the
              same  as  Left  and  Right,  respectively.   Meta-b  and  Meta-f behave the same as
              Control-Left and Control-Right, respectively.

       [10]   The Up and Down keys move the insertion cursor one line up or down  and  clear  any
              selection  in  the text.  If Up or Right is typed with the Shift key down, then the
              insertion cursor moves and the selection is extended to include the new  character.
              Control-Up  and  Control-Down  move  the  insertion cursor by paragraphs (groups of
              lines separated by blank lines), and Control-Shift-Up and  Control-Shift-Down  move
              the  insertion  cursor  by paragraphs and also extend the selection.  Control-p and
              Control-n behave the same as Up and Down, respectively.

       [11]   The Next and Prior keys move the insertion  cursor  forward  or  backwards  by  one
              screenful and clear any selection in the text.  If the Shift key is held down while
              Next or Prior is  typed,  then  the  selection  is  extended  to  include  the  new
              character.   Control-v  moves  the  view  down  one  screenful  without  moving the
              insertion cursor or adjusting the selection.

       [12]   Control-Next and Control-Prior scroll the view right or left by  one  page  without
              moving the insertion cursor or affecting the selection.

       [13]   Home and Control-a move the insertion cursor to the beginning of its line and clear
              any selection in  the  widget.   Shift-Home  moves  the  insertion  cursor  to  the
              beginning of the line and also extends the selection to that point.

       [14]   End  and  Control-e  move the insertion cursor to the end of the line and clear any
              selection in the widget.  Shift-End moves the cursor to the end  of  the  line  and
              extends the selection to that point.

       [15]   Control-Home  and Meta-< move the insertion cursor to the beginning of the text and
              clear any selection in the widget.  Control-Shift-Home moves the  insertion  cursor
              to the beginning of the text and also extends the selection to that point.

       [16]   Control-End  and  Meta-> move the insertion cursor to the end of the text and clear
              any selection in the widget.  Control-Shift-End moves the cursor to the end of  the
              text and extends the selection to that point.

       [17]   The  Select  key  and Control-Space set the selection anchor to the position of the
              insertion cursor.  They don't  affect  the  current  selection.   Shift-Select  and
              Control-Shift-Space  adjust  the selection to the current position of the insertion
              cursor, selecting from the anchor to the insertion cursor  if  there  was  not  any
              selection previously.

       [18]   Control-/ selects the entire contents of the widget.

       [19]   Control-\ clears any selection in the widget.

       [20]   The F16 key (labelled Copy on many Sun workstations) or Meta-w copies the selection
              in the widget to the clipboard, if there is a selection.  This  action  is  carried │
              out by the command tk_textCopy.

       [21]   The  F20  key  (labelled  Cut  on  many  Sun  workstations) or Control-w copies the
              selection in the widget to the clipboard and deletes the selection.  This action is │
              carried out by the command tk_textCut.  If there is no selection in the widget then
              these keys have no effect.

       [22]   The F18 key (labelled Paste on many Sun  workstations)  or  Control-y  inserts  the
              contents  of the clipboard at the position of the insertion cursor.  This action is │
              carried out by the command tk_textPaste.

       [23]   The Delete key deletes the selection, if there is one in the widget.  If  there  is
              no selection, it deletes the character to the right of the insertion cursor.

       [24]   Backspace  and  Control-h  delete the selection, if there is one in the widget.  If
              there is no selection, they delete the character  to  the  left  of  the  insertion
              cursor.

       [25]   Control-d deletes the character to the right of the insertion cursor.

       [26]   Meta-d deletes the word to the right of the insertion cursor.

       [27]   Control-k  deletes  from  the  insertion  cursor  to  the  end  of its line; if the
              insertion cursor is already at the end  of  a  line,  then  Control-k  deletes  the
              newline character.

       [28]   Control-o  opens  a  new  line  by  inserting  a  newline character in front of the
              insertion cursor without moving the insertion cursor.

       [29]   Meta-backspace and Meta-Delete delete the word to the left of the insertion cursor.

       [30]   Control-x deletes whatever is selected in the text widget after copying it  to  the
              clipboard.

       [31]   Control-t  reverses  the  order of the two characters to the right of the insertion
              cursor.

       [32]   Control-z (and Control-underscore on UNIX when tk_strictMotif is true)  undoes  the │
              last edit action if the -undo option is true.  Does nothing otherwise.              │

       [33]                                                                                       │
              Control-Z  (or  Control-y  on Windows) reapplies the last undone edit action if the │
              -undo option is true. Does nothing otherwise.

       If the widget is disabled using the -state option, then its view can still be adjusted and
       text  can  still  be  selected,  but  no  insertion  cursor  will be displayed and no text
       modifications will take place.

       The behavior of texts can be changed by defining new bindings for individual widgets or by
       redefining the class bindings.

PERFORMANCE ISSUES

       Text  widgets  should run efficiently under a variety of conditions.  The text widget uses
       about 2-3 bytes of main memory for each byte of text, so texts containing  a  megabyte  or
       more  should  be  practical  on  most workstations.  Text is represented internally with a
       modified B-tree structure that makes  operations  relatively  efficient  even  with  large
       texts.   Tags are included in the B-tree structure in a way that allows tags to span large
       ranges or have many disjoint smaller ranges without loss of efficiency.   Marks  are  also
       implemented in a way that allows large numbers of marks.  In most cases it is fine to have
       large numbers of unique tags, or a tag that has many distinct ranges.

       One performance problem can arise if you have hundreds or thousands of different tags that
       all have the following characteristics: the first and last ranges of each tag are near the
       beginning and end of the text, respectively, or a single tag range covers most of the text
       widget.   The  cost of adding and deleting tags like this is proportional to the number of
       other tags with the same properties.   In  contrast,  there  is  no  problem  with  having
       thousands  of  distinct  tags  if  their overall ranges are localized and spread uniformly
       throughout the text.

       Very long text lines can be expensive, especially if they have many marks and tags  within
       them.

       The  display  line  with  the  insert cursor is redrawn each time the cursor blinks, which
       causes a steady stream of graphics traffic.  Set the insertOffTime attribute  to  0  avoid
       this.

SEE ALSO

       entry(3tk), scrollbar(3tk)

KEYWORDS

       text, widget, tkvars