Provided by: tk8.5-doc_8.5.11-1_all bug

NAME

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

SYNOPSIS

       text pathName ?options?
       tk_textCopy pathName
       tk_textCut pathName
       tk_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

       Command-Line Name:-autoseparators
       Database Name:  autoSeparators
       Database Class: AutoSeparators

              Specifies  a boolean that says whether separators are automatically inserted in the
              undo stack. Only meaningful when the -undo option is true.

       Command-Line Name:-blockcursor
       Database Name:  blockCursor
       Database Class: BlockCursor

              Specifies a boolean that says whether the blinking insertion cursor should be drawn │
              as  a  character-sized  rectangular  block.  If false (the default) a thin vertical │
              line is used for the insertion cursor.

       Command-Line Name:-endline
       Database Name:  endLine
       Database Class: EndLine

              Specifies an integer line index  representing  the  last  line  of  the  underlying │
              textual  data  store  that  should  be contained in the widget.  This allows a text │
              widget to reflect only a portion of  a  larger  piece  of  text.    Instead  of  an │
              integer,  the empty string can be provided to this configuration option, which will │
              configure the widget to end at the very last line in the textual data store.

       Command-Line Name:-height
       Database Name:  height
       Database Class: 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.

       Command-Line Name:-inactiveselectbackground
       Database Name:  inactiveSelectBackground
       Database Class: Foreground

              Specifies  the  colour  to use for the selection (the sel tag) when the window does │
              not have the input focus.  If empty, {}, then no selection is shown when the window │
              does not have the focus.

       Command-Line Name:-maxundo
       Database Name:  maxUndo
       Database Class: MaxUndo

              Specifies  the maximum number of compound undo actions on the undo stack. A zero or
              a negative value imply an unlimited undo stack.

       Command-Line Name:-spacing1
       Database Name:  spacing1
       Database Class: 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.

       Command-Line Name:-spacing2
       Database Name:  spacing2
       Database Class: 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.

       Command-Line Name:-spacing3
       Database Name:  spacing3
       Database Class: 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.

       Command-Line Name:-startline
       Database Name:  startLine
       Database Class: StartLine

              Specifies  an  integer  line  index  representing  the first line of the underlying │
              textual data store that should be contained in the  widget.   This  allows  a  text │
              widget to reflect only a portion of a larger piece of text.  Instead of an integer, │
              the empty string can be provided to this configuration option, which will configure │
              the widget to start at the very first line in the textual data store.

       Command-Line Name:-state
       Database Name:  state
       Database Class: 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.

       Command-Line Name:-tabs
       Database Name:  tabs
       Database Class: 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.   To  achieve  a
              different  standard  spacing,  for example every 4 characters, simply configure the
              widget  with  “-tabs  "[expr  {4  *  [font  measure  $font  0]}]  left"   -tabstyle
              wordprocessor”.

       Command-Line Name:-tabstyle
       Database Name:  tabStyle
       Database Class: TabStyle

              Specifies how to interpret the relationship between tab stops on a line and tabs in
              the text of that line.  The value must be tabular (the default)  or  wordprocessor.
              Note  that  tabs  are  interpreted as they are encountered in the text.  If the tab
              style is tabular then the n'th tab character in the line's text will be  associated
              with  the n'th tab stop defined for that line.  If the tab character's x coordinate
              falls to the right of the n'th tab stop, then a gap  of  a  single  space  will  be
              inserted  as  a fallback.  If the tab style is wordprocessor then any tab character
              being laid out will use (and be defined by) the first tab stop to the right of  the
              preceding  characters  already  laid  out  on that line.  The value of the tabstyle
              option may be overridden by -tabstyle options in tags.

       Command-Line Name:-undo
       Database Name:  undo
       Database Class: Undo

              Specifies a boolean that says whether the undo mechanism is active or not.

       Command-Line Name:-width
       Database Name:  width
       Database Class: Width

              Specifies the desired width for the window in units of characters in the font given
              by  the  -font option.  If the font does not have a uniform width then the width of
              the character “0” is used in translating from character units to screen units.

       Command-Line Name:-wrap
       Database Name:  wrap
       Database Class: 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 do not 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.

       The text widget allows for the creation of peer widgets.  These  are  other  text  widgets │
       which  share  the same underlying data (text, marks, tags, images, etc).  See PEER WIDGETS │
       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.  Most  modifiers  (as  documented  below)  allow  an  optional │
       submodifier.   Valid  submodifiers are any and display. If the submodifier is abbreviated, │
       then it must be followed by whitespace, but otherwise there need be no space  between  the │
       submodifier  and  the  following  modifier.  Typically the display submodifier adjusts the │
       meaning of the following modifier to make it refer to visual or  non-elided  units  rather │
       than  logical  units,  but  this is explained for each relevant case below.  Lastly, where │
       count is used as part of a modifier, it can be positive or negative, so “base - -3  lines” │
       is perfectly valid (and equivalent to “base +3lines”).

       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 ?submodifier? 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 index in the text.  Spaces on either side  of │
              count  are  optional.   If  the display submodifier is given, elided characters are │
              skipped over without being counted.  If any  is  given,  then  all  characters  are │
              counted.   For  historical  reasons,  if  neither  modifier is given then the count │
              actually takes place in units of index positions (see indices for  details).   This │
              behaviour  may be changed in a future major release, so if you need an index count, │
              you are encouraged to use indices instead wherever possible.

       - count ?submodifier? 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 index in the text (1.0).  Spaces  on │
              either  side  of  count  are optional.  If the display submodifier is given, elided │
              characters are skipped over without being counted.   If  any  is  given,  then  all │
              characters  are counted.  For historical reasons, if neither modifier is given then │
              the count actually takes place  in  units  of  index  positions  (see  indices  for │
              details).   This behaviour may be changed in a future major release, so if you need │
              an index count, you are encouraged to use indices instead wherever possible.

       + count ?submodifier? indices
              Adjust the index forward by count index positions, moving to  later  lines  in  the │
              text if necessary.  If there are fewer than count index positions in the text after │
              the current index, then set the index to the  last  index  position  in  the  text. │
              Spaces on either side of count are optional.  Note that an index position is either │
              a single character or a single embedded image or embedded window.  If  the  display │
              submodifier  is  given,  elided indices are skipped over without being counted.  If │
              any is given, then all indices are counted; this is also the default  behaviour  if │
              no modifier is given.

       - count ?submodifier? indices
              Adjust  the index backward by count index positions, moving to earlier lines in the │
              text if necessary.  If there are fewer than  count  index  positions  in  the  text │
              before  the  current index, then set the index to the first index position (1.0) in │
              the text.  Spaces on either side of count are optional.  If the display submodifier │
              is  given, elided indices are skipped over without being counted.  If any is given, │
              then all indices are counted; this is also the default behaviour if no modifier  is │
              given.

       + count ?submodifier? 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.   If  the  display submodifier is given, then each visual display line is │
              counted separately.  Otherwise, if any (or no modifier) is given, then each logical │
              line  (no  matter  how many times it is visually wrapped) counts just once.  If the │
              relevant lines are not wrapped, then these two methods of counting are equivalent.

       - count ?submodifier? lines
              Adjust the index backward by count logical  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.  If the display submodifier is given, then  each │
              visual  display  line is counted separately.  Otherwise, if any (or no modifier) is │
              given, then each logical line (no matter how many times  it  is  visually  wrapped) │
              counts just once.  If the relevant lines are not wrapped, then these two methods of │
              counting are equivalent.

       ?submodifier? linestart
              Adjust the index to refer  to  the  first  index  on  the  line.   If  the  display │
              submodifier is given, this is the first index on the display line, otherwise on the │
              logical line.

       ?submodifier? lineend
              Adjust the index to refer to the last index on the  line  (the  newline).   If  the │
              display submodifier is given, this is the last index on the display line, otherwise │
              on the logical line.

       ?submodifier? 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.   If  the │
              display  submodifier  is given, this only examines non-elided characters, otherwise │
              all characters (elided or not) are examined.

       ?submodifier? 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 the display submodifier is given,  this  only │
              examines  non-elided  characters,  otherwise  all  characters  (elided  or not) are │
              examined.                                                                           │

       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”.          │

       Where  modifiers  result  in  index  changes  by  display  lines, display chars or display │
       indices, and the base refers to an  index  inside  an  elided  tag,  that  base  index  is │
       considered to be equivalent to the first following non-elided index.

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  cannot  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  has  not  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 (characters,
              images, embedded windows, etc) 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 has not 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 non-elided 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 non-elided character of that display
              line.

       -lmargin1 pixels
              If the first non-elided 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 non-elided 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 non-elided 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 non-elided 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 non-elided 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.

       -tabstyle style
              Style specifies either the tabular or wordprocessor style of tabbing to use for the
              text widget.  This option only applies to a display line if it applies to the first
              non-elided 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).

       -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 has
       not 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
       “pathName tag bind” widget command below.   Tag  bindings  are  shared  between  all  peer │
       widgets (including any bindings for the special sel tag).

       The  third  use for tags is in managing the selection.  See THE SELECTION below.  With the │
       exception of the special sel tag, all tags are shared between peer text widgets,  and  may │
       be  manipulated on an equal basis from any such widget.  The sel tag exists separately and │
       independently in each peer text widget (but any tag bindings to sel are shared).

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 is not 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.  With the exception of these two special marks, all marks are shared │
       between peer text widgets, and may be manipulated on an equal basis from any peer.

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 unit'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.  Similarly if the text widget as a whole is │
       deleted, then the window is destroyed.

       When an embedded window is added to a text widget with the pathName window  create  widget
       command,  several  configuration  options may be associated with it.  These options may be
       modified later with the pathName 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.  Two substitutions will be performed in  script  before  evaluation. │
              %W  will  be  substituted  by  the  name  of the parent text widget, and %% will be │
              substituted by a single %.  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.   Note  that  if  a │
              pathName has been set, then later configuring a window to the empty string will not │
              delete the widget corresponding to the old pathName.  Rather  it  will  remove  the │
              association between the old pathName and the text widget.  If multiple peer widgets │
              are in use, it is usually simpler to use the -create option if embedded windows are │
              desired in each peer.

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 │
       unit'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 pathName 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 pathName 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 pathName image configure.

       When an embedded image is added to a text widget with the  pathName  image  create  widget
       command,  several  configuration  options may be associated with it.  These options may be
       modified later with the pathName 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.  Also the -inactiveselectbackground option │
       for the text widget is used instead of -selectbackground when the  text  widget  does  not │
       have  the  focus.   This allows programmatic control over the visualization of the sel tag │
       for  foreground  and  background  windows,  or  to  have  sel  not  shown  at  all   (when │
       -inactiveselectbackground is empty) for background windows.  Each peer text widget has its │
       own sel tag which can be separately configured and set.

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  pathName  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 pathName edit widget command that controls the undo mechanism.

PEER WIDGETS

       The  text  widget  has  a  separate  store  of all its data concerning each line's textual │
       contents, marks, tags, images and windows, and the undo stack.                             │

       While this data store cannot be accessed directly  (i.e.  without  a  text  widget  as  an │
       intermediary), multiple text widgets can be created, each of which present different views │
       on the same underlying data.  Such text widgets are known as peer text widgets.            │

       As text is added, deleted, edited and coloured in any one widget, and  as  images,  marks, │
       tags are adjusted, all such changes will be reflected in all peers.                        │

       All  data and markup is shared, except for a few small details.  First, the sel tag may be │
       set and configured (in its display style) differently for each peer.   Second,  each  peer │
       has  its  own  insert and current mark positions (but all other marks are shared).  Third, │
       embedded windows, which are arbitrary other widgets, cannot be shared between peers.  This │
       means  the  -window  option  of embedded windows is independently set for each peer (it is │
       advisable to use the -create script capabilities to allow each  peer  to  create  its  own │
       embedded  windows as needed).  Fourth, all of the configuration options of each peer (e.g. │
       -font,  etc)  can  be  set  independently,  with  the  exception   of   -undo,   -maxUndo, │
       -autoSeparators (i.e. all undo, redo and modified state issues are shared).                │

       Finally  any  single peer need not contain all lines from the underlying data store.  When │
       creating a peer, a contiguous range of lines (e.g.  only lines  52  through  125)  may  be │
       specified.   This  allows a peer to contain just a small portion of the overall text.  The │
       range of lines will expand and contract as text is inserted or  deleted.   The  peer  will │
       only  ever  display complete lines of text (one cannot share just part of a line).  If the │
       peer's contents contracts to nothing (i.e. all complete lines in the peer widget have been │
       deleted  from  another  widget),  then it is impossible for new lines to be inserted.  The │
       peer will simply become an empty shell on which the  background  can  be  configured,  but │
       which  will  never  show  any content (without manual reconfiguration of the start and end │
       lines).  Note that a peer which does not contain all of the underlying  data  store  still │
       has  indices  numbered  from  “1.0”  to  “end”.  It is simply that those indices reflect a │
       subset of the total data, and data outside the contained range is not  accessible  to  the │
       peer.  This means that the command peerName index end may return quite different values in │
       different peers.  Similarly, commands like peerName  tag  ranges  will  not  return  index │
       ranges outside that which is meaningful to the peer.  The configuration options -startline │
       and -endline may be used to control how much of the underlying data is  contained  in  any │
       given text widget.                                                                         │

       Note  that peers are really peers.  Deleting the “original” text widget will not cause any │
       other peers to be deleted, or otherwise affected.                                          │

       See below for the pathName peer widget command that controls the creation of peer widgets.

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 is
              not.  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 count ?options? index1 index2                                                     │
              Counts  the  number of relevant things between the two indices.  If index1 is after │
              index2, the result will be a negative number  (and  this  holds  for  each  of  the │
              possible options).  The actual items which are counted depend on the options given. │
              The result is a list of integers, one for the result of each counting option given. │
              Valid  counting  options are -chars, -displaychars, -displayindices, -displaylines, │
              -indices, -lines, -xpixels and  -ypixels.  The  default  value,  if  no  option  is │
              specified,  is  -indices. There is an additional possible option -update which is a │
              modifier.  If given, then all subsequent options ensure that any  possible  out  of │
              date  information  is  recalculated.   This  currently  only has any effect for the │
              -ypixels count (which, if -update is not given, will use the text widget's  current │
              cached value for each line).  The count options are interpreted as follows:         │

              -chars                                                                              │
                     count  all characters, whether elided or not.  Do not count embedded windows │
                     or images.                                                                   │

              -displaychars                                                                       │
                     count all non-elided characters.                                             │

              -displayindices                                                                     │
                     count all non-elided characters, windows and images.                         │

              -displaylines                                                                       │
                     count all display lines (i.e. counting one for each time a line wraps)  from │
                     the line of the first index up to, but not including the display line of the │
                     second index.  Therefore if they are both on the  same  display  line,  zero │
                     will be returned.  By definition displaylines are visible and therefore this │
                     only counts portions of actual visible lines.                                │

              -indices                                                                            │
                     count all characters and embedded windows or images (i.e.  everything  which │
                     counts in text-widget index space), whether they are elided or not.          │

              -lines                                                                              │
                     count  all  logical  lines  (irrespective  of wrapping) from the line of the │
                     first index up  to,  but  not  including  the  line  of  the  second  index. │
                     Therefore if they are both on the same line, zero will be returned.  Logical │
                     lines are counted whether they are currently visible (non-elided) or not.    │

              -xpixels                                                                            │
                     count the number of horizontal pixels from the  first  pixel  of  the  first │
                     index  to (but not including) the first pixel of the second index.  To count │
                     the total desired width  of  the  text  widget  (assuming  wrapping  is  not │
                     enabled),  first  find  the  longest line and then use “.text count -xpixels │
                     "${line}.0" "${line}.0 lineend"”.                                            │

              -ypixels                                                                            │
                     count the number of vertical pixels from the first pixel of the first  index │
                     to (but not including) the first pixel of the second index.  If both indices │
                     are on the same display line, zero will be returned.   To  count  the  total │
                     number  of vertical pixels in the text widget, use “.text count -ypixels 1.0 │
                     end”, and to ensure this is up to date, use “.text  count  -update  -ypixels │
                     1.0 end”.                                                                    │

              The  command  returns a positive or negative integer corresponding to the number of │
              items counted between the two indices.  One  such  integer  is  returned  for  each │
              counting  option given, so a list is returned if more than one option was supplied. │
              For example “.text count -xpixels -ypixels 1.3 4.5” is  perfectly  valid  and  will │
              return a list of two elements.                                                      │

       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 does not specify a position later in the text than index1 then no characters
              are  deleted.   If  index2  is not 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 so 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 ?-displaychars? -- 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 pathName get.  If the -displaychars option is given,  then,  within  each │
              range,  only those characters which are not elided will be returned.  This may have │
              the effect that some of the returned ranges are empty strings.

       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 pathName 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
                     pathName  dump  operation.  If a mark has been set to the special end index,
                     then it appears to be after end with  respect  to  the  pathName  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 pathName 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 pathName 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
                     does  not  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 peer option args
              This command is used to create and query widget peers.  It has two forms, depending │
              on option:                                                                          │

              pathName peer create newPathName ?options?                                          │
                     Creates a peer text widget with the  given  newPathName,  and  any  optional │
                     standard  configuration  options  (as for the text command).  By default the │
                     peer will have the same start and end line as the parent widget,  but  these │
                     can be overridden with the standard configuration options.                   │

              pathName peer names                                                                 │
                     Returns  a  list  of  peers of this widget (this does not include the widget │
                     itself).  The order within this list is undefined.                           │

       pathName replace index1 index2 chars ?tagList chars tagList ...?                           │
              Replaces the  range  of  characters  between  index1  and  index2  with  the  given │
              characters  and tags.  See the section on pathName insert for an explanation of the │
              handling of the tagList...  arguments, and the section on pathName  delete  for  an │
              explanation  of  the  handling  of  the indices.  If index2 corresponds to an index │
              earlier in the text than index1, an error will be generated.                        │

              The deletion and insertion are arranged so that no  unnecessary  scrolling  of  the │
              window or movement of insertion cursor occurs.  In addition the undo/redo stack are │
              correctly modified, if undo operations are active in the text widget.  The  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  pathName  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 pathName 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 (it is not │
                     allowed to be at index).  Note that, for a  variety  of  reasons,  backwards │
                     searches  can  be  substantially slower than forwards searches (particularly │
                     when using -regexp), so it is recommended that performance-critical code use │
                     forward searches.

              -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).  The │
                     default matching automatically passes both  the  -lineanchor  and  -linestop │
                     options  to the regexp engine (unless -nolinestop is used), so that ^$ match │
                     beginning and end of line, and ., [^ sequences will never match the  newline │
                     character \n.

              -nolinestop
                     This allows . and [^ sequences to match the newline character \n, which they │
                     will otherwise not do (see the regexp command for details). This  option  is │
                     only  meaningful  if  -regexp  is  also  given,  and an error will be thrown │
                     otherwise.  For example, to match the  entire  text,  use  “pathName  search-nolinestop -regexp ".*" 1.0”.

              -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.

              -all   Find  all matches in the given range and return a list of the indices of the │
                     first character of each match.  If a -count varName switch  is  given,  then │
                     varName  is  also  set  to a list containing one element for each successful │
                     match.  Note that, even for exact searches, the elements of this list may be │
                     different,  if  there are embedded images, windows or hidden text.  Searches │
                     with -all behave very similarly to the Tcl  command  regexp  -all,  in  that │
                     overlapping  matches  are  not  normally returned.  For example, applying an │
                     -all search of the pattern “\w+”  against  “hello  there”  will  just  match │
                     twice,  once for each word, and matching “Z[a-z]+Z” against “ZooZooZoo” will │
                     just match once.

              -overlap
                     When performing -all searches, the normal behaviour is  that  matches  which │
                     overlap  an  already-found  match will not be returned.  This switch changes │
                     that behaviour so that all matches which are  not  totally  enclosed  within │
                     another match are returned.  For example, applying an -overlap search of the │
                     pattern “\w+” against “hello there” will just match twice (i.e. no different │
                     to  just  -all),  but matching “Z[a-z]+Z” against “ZooZooZoo” will now match │
                     twice.  An error will be thrown if this switch is used without -all.

              -strictlimits
                     When performing any search, the normal behaviour is that the start and  stop │
                     limits are checked with respect to the start of the matching text.  With the │
                     -strictlimits flag, the entire matching range must lie inside the start  and │
                     stop limits specified for the match to be valid.

              -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  may  be  within a single line of text, or run across multiple │
              lines (if parts of the pattern can  match  a  new-line).   For  regular  expression │
              matching  one  can use the various newline-matching features such as $ to match the │
              end of a line, ^ to match the beginning of a line, and  to  control  whether  .  is │
              allowed  to  match a new-line.  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.   This means that, for example, if the search is -forwards but
              stopIndex is earlier in the text than startIndex, nothing will ever be found.   See
              KNOWN BUGS below for a number of minor limitations of the pathName search command.

       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 is  not  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 pathName tag configure widget command.

              pathName tag configure tagName ?option? ?value? ?option value ...?
                     This command is similar to the pathName 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 have not 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 is not affected).  A
                     single command may contain any number of index1-index2 pairs.  If  the  last
                     index2  is  omitted  then  the  tag  is removed from the single character at
                     index1.  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.   What must be units, pages or pixels.  If what is units or pages │
                     then number must be an integer, otherwise number may be specified in any  of │
                     the  forms acceptable to Tk_GetPixels, such as “2.0c” or “1i” (the result is │
                     rounded to the nearest integer value.  If no units  are  given,  pixels  are │
                     assumed).   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  it  is pixels then the view adjusts by │
                     number pixels.  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  visible
                     pixel  of the first character (or image, etc) 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 first pixel just
                     after the last visible 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 pixel given by  fraction  appears
                     at  the top of the top line of the window.  Fraction is a fraction between 0
                     and 1;  0 indicates the first pixel of the first character in the text, 0.33
                     indicates  the  pixel that is one-third the way through the text; and so on. │
                     Values close to 1 will indicate values close to the last pixel in  the  text │
                     (1  actually  refers  to one pixel beyond the last pixel), but in such cases │
                     the widget will never scroll beyond the last pixel, and so a value of 1 will │
                     effectively  be  rounded back to whatever fraction ensures the last pixel is │
                     at the bottom of the window, and some other pixel is at the top.

              pathName yview scroll number what
                     This command adjust the view in the window up or down  according  to  number
                     and  what.   What must be units, pages or pixels.  If what is units or pages │
                     then number must be an integer, otherwise number may be specified in any  of │
                     the  forms acceptable to Tk_GetPixels, such as “2.0c” or “1i” (the result is │
                     rounded to the nearest integer value.  If no units  are  given,  pixels  are │
                     assumed).   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 │
                     it  is pixels then the view adjusts by number pixels.  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 is not 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 pathName see widget command
                     (pathName see handles both x- and  y-motion  to  make  a  location  visible,
                     whereas the -pickplace mode 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(3tk).

       [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 start 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 start 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.

       [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  display  line
              and  clear  any  selection in the widget.  Shift-Home moves the insertion cursor to
              the beginning of the display line and also extends the selection to that point.

       [14]   End and Control-e move the insertion cursor to the end  of  the  display  line  and
              clear  any  selection  in the widget.  Shift-End moves the cursor to the end of the
              display 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  do  not  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.

KNOWN ISSUES

   ISSUES CONCERNING CHARS AND INDICES
       Before Tk 8.5, the widget used the string “chars”  to  refer  to  index  positions  (which │
       included  characters, embedded windows and embedded images).  As of Tk 8.5 the text widget │
       deals separately and correctly with “chars” and “indices”.  For  backwards  compatibility, │
       however,  the index modifiers “+N chars” and “-N chars” continue to refer to indices.  One │
       must use any of the full forms “+N any chars” or “-N any chars” etc. to  refer  to  actual │
       character  indices.   This confusion may be fixed in a future release by making the widget │
       correctly interpret “+N chars” as a synonym for “+N any chars”.

   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.

   KNOWN BUGS
       The pathName search -regexp sub-command attempts to perform sophisticated regexp  matching │
       across  multiple  lines  in  an  efficient  fashion  (since  Tk  8.5), examining each line │
       individually, and then in small groups of lines, whether searching forwards or  backwards. │
       Under certain conditions the search result might differ from that obtained by applying the │
       same regexp to the entire text from the widget in one go.   For  example,  when  searching │
       with  a greedy regexp, the widget will continue to attempt to add extra lines to the match │
       as long as one of two conditions are true: either Tcl's regexp library returns a  code  to │
       indicate  a longer match is possible (but there are known bugs in Tcl which mean this code │
       is not always correctly returned); or if each extra line  added  results  in  at  least  a │
       partial  match  with the pattern.  This means in the case where the first extra line added │
       results in no match and Tcl's regexp system returns the incorrect code and adding a second │
       extra  line  would  actually  match,  the  text  widget  will return the wrong result.  In │
       practice this is a rare problem, but it can occur, for example:                            │
              pack [text .t]                                                                      │
       will not find a match when one exists of 19 characters starting from the first “b”.        │

       Whenever one possible match is fully enclosed in another, the search command will  attempt │
       to ensure only the larger match is returned.  When performing backwards regexp searches it │
       is possible that Tcl will not always achieve this, in the case where a match  is  preceded │
       by  one or more short, non-overlapping matches, all of which are preceded by a large match │
       which actually encompasses all of them.  The search algorithm used by the widget does  not │
       look  back  arbitrarily  far  for a possible match which might cover large portions of the │
       widget.  For example:                                                                      │
              pack [text .t]                                                                      │
       matches at “5.0” when a true greedy match would match at “1.0”.  Similarly if we add  -all │
       to  this  case,  it matches at all of “5.0”, “4.0”, “3.0” and “1.0”, when really it should │
       only match at “1.0” since that match encloses all the others.

SEE ALSO

       entry(3tk), scrollbar(3tk)

KEYWORDS

       text, widget, tkvars