text(n)                      Tk Built-In Commands                      text(n)



NAME
       text - Create and manipulate text widgets

SYNOPSIS
       (text widget-name ?options?)
       :background    :highlightbackground     :insertontime  :selectborderwidth
       :borderwidth   :highlightcolor     :insertwidth   :selectforeground
       :cursor   :highlightthickness :padx     :setgrid
       :exportselection    :insertbackground   :pady     :takefocus
       :font     :insertborderwidth  :relief   :xscrollcommand
       :foreground    :insertofftime :selectbackground   :yscrollcommand

WIDGET-SPECIFIC OPTIONS
       [:height height] Specifies the desired height for the window, in units
       of characters in the font given by the :font option.  Must be at least
       one.  [:spacing1 spacing1] Requests additional space above each text
       line in the widget, using any of the standard forms for screen
       distances.  If a line wraps, this option only applies to the first line
       on the display.  This option may be overriden with :spacing1 options in
       tags.  [:spacing2 spacing2] For lines that wrap (so that they cover
       more than one line on the display) this option specifies additional
       space to provide between the display lines that represent a single line
       of text.  The value may have any of the standard forms for screen
       distances.  This option may be overriden with :spacing2 options in
       tags.  [:spacing3 spacing3] Requests additional space below each text
       line in the widget, using any of the standard forms for screen
       distances.  If a line wraps, this option only applies to the last line
       on the display.  This option may be overriden with :spacing3 options in
       tags.  [:state state] Specifies one of two states for the text:  normal
       or disabled.  If the text is disabled then characters may not be
       inserted or deleted and no insertion cursor will be displayed, even if
       the input focus is in the widget.  [:tabs tabs] Specifies a set of tab
       stops for the window.  The option's value consists of a list of screen
       distances giving the positions of the tab stops.  Each 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.  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.  [:width width] Specifies
       the desired width for the window in units of characters in the font
       given by the :font option.  If the font doesn't have a uniform width
       then the width of the character ``0'' is used in translating from
       character units to screen units.  [:wrap wrap] Specifies how to handle
       lines in the text that are too long to be displayed in a single line of
       the text's window.  The value must be none or char or word.  A wrap
       mode of none means that each line of text appears as exactly one line
       on the screen;  extra characters that don't fit on the screen are not
       displayed.  In the other modes each line of text will be broken up into
       several screen lines if necessary to keep all the characters visible.
       In char mode a screen line break may occur after any character; in word
       mode a line break will only be made at word boundaries.


DESCRIPTION
       The text procedure creates a new window (given by the widget-name
       argument) and makes it into a text widget.  Additional options,
       described above, may be specified on the procedure line or in the
       option database to configure aspects of the text such as its default
       background color and relief.  The text procedure 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, STk procedures 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 marks, which are floating
       markers in the text.  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.


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

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

       line.char

       (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.

       @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.

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

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

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

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

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

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

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

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

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

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

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

       If more than one modifier is present then they are applied in left-to-
       right order.  For example, the index ``end - 1 chars'' refers to the
       next-to-last character in the text and ``insert wordstart - 1 c''
       refers to the character just before the first one in the word
       containing the insertion cursor.

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 the characters `` '' (space), +, or :: these
       characters have special meaning in indices, so tags containing them
       can't be used as indices.  There may be any number of tags associated
       with characters in a text.  Each tag may refer to a single character, a
       range of characters, or several ranges of characters.  An individual
       character may have any number of tags associated with it.

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

       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 ``widget-name tag configure'' widget
       procedure.  If a character has been tagged, then the display options
       associated with the tag override the default display style.  The
       following options are currently supported for tags:

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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


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

       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 right of the mark.  The gravity for a
       mark defaults to right.

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

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


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

       When an embedded window is added to a text widget with the window
       create widget procedure, several configuration options may be
       associated with it.  These options may be  modified later with the
       window configure widget procedure.  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 procedure
              Specifies a STk procedure 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 that window
              as its result.  If the annotation's window should ever be
              deleted, procedure 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 widget-name
              Specifies the window to display in the annotation.


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

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

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

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

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

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

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

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




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

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

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

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

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


THE INSERTION CURSOR
       The mark named insert has special significance in text widgets.  It is
       defined automatically when a text widget is created and it may not be
       unset with the ``widget-name mark unset'' widget procedure.  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.


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

       (widget-name '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.

       (widget-name 'cget option)
              Returns the current value of the configuration option given by
              option.  Option may have any of the values accepted by the text
              procedure.

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

       (widget-name '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 widget-name (see Tk_ConfigureInfo for
              information on the format of this list).  If option is specified
              with no value, then the procedure 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 procedure modifies the given widget option(s) to have
              the given value(s);  in this case the procedure returns an empty
              string.  Option may have any of the values accepted by the text
              procedure.

       (widget-name 'debug )

       (widget-name '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 procedure returns an empty string.  If boolean is not
              specified then the procedure 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.

       (widget-name 'delete index1 )

       (widget-name 'delete index1 index2)
              Delete a range of characters from the text.  If both index1 and
              index2 are specified, then delete all the characters starting
              with the one given by index1 and stopping just before index2
              (i.e. the character at index2 is not deleted).  If index2
              doesn't specify a position later in the text than index1 then no
              characters are deleted.  If index2 isn't specified then the
              single character at index1 is deleted.  It is not allowable to
              delete characters in a way that would leave the text without a
              newline as the last character.  The procedure returns an empty
              string.

       (widget-name '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.

       (widget-name '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, and
              window.  The corresponding value is the text, mark name, tag
              name, or window name.  The index information is the index of the
              start of the text, the mark, the tag transition, or the 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,
                     and windows.  This is the default.

              :command closure
                     Instead of returning the information as the result of the
                     dump operation, invoke the closure on each element of the
                     text widget within the range.  The command must have
                     three arguments:  key, value, and index.

              :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 seqments 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.

       (widget-name 'get index1 )

       (widget-name 'get index1 index2)
              Return a range of characters from the text.  The return value
              will be all the characters in the text starting with the one
              whose index is index1 and ending just before the one whose index
              is index2 (the character at index2 will not be returned).  If
              index2 is omitted then the single character at index1 is
              returned.  If there are no characters in the specified range
              (e.g. index1 is past the end of the file or index2 is less than
              or equal to index1) then an empty string is returned.  If the
              specified range contains embedded windows, no information about
              them is included in the returned string.


       (widget-name '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:

              (widget-name '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.

              (widget-name '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.

              (Widget-name '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.

              (Widget-name 'image 'names)
                     Returns a list whose elements are the names of all image
                     instances currently embedded in window.

       (widget-name '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.

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

       (widget-name 'mark option ?arg arg ...?)
              This procedure is used to manipulate marks.  The exact behavior
              of the procedure depends on the option argument that follows the
              mark argument.  The following forms of the procedure are
              currently supported:

              (widget-name 'mark 'gravity markName)

              (widget-name '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.

              (widget-name 'mark 'names)
                     Returns a list whose elements are the names of all the
                     marks that are currently set.

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

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

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

              (widget-name '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
                     ``widget-name mark names''.  This procedure returns an
                     empty string.

       (widget-name 'scan option args)
              This procedure is used to implement scanning on texts.  It has
              two forms, depending on option:

              (widget-name 'scan 'mark x y)
                     Records x and y and the current view in the text window,
                     for use in conjunction with later scan dragto procedures.
                     Typically this procedure is associated with a mouse
                     button press in the widget.  It returns an empty string.

              (widget-name 'scan 'dragto x y)
                     This procedure computes the difference between its x and
                     y arguments and the x and y arguments to the last scan
                     mark procedure for the widget.  It then adjusts the view
                     by 10 times the difference in coordinates.  This
                     procedure 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.

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

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

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

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

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

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

              :count varName
                     The argument following :count gives the name of a
                     variable; if a match is found, the number of characters
                     in the matching range will be stored in the variable.

              :environment env
                     The argument following :environment gives the definition
                     environment of the variable counting matches (i.e. the
                     one given to the  :count option).  :- This switch has no
                     effect except to terminate the list of switches: the next
                     argument will be treated as pattern even if it starts
                     with :.

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

       (widget-name '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 procedure does nothing.  If index is a short distance out of
              view, the procedure adjusts the view just enough to make index
              visible at the edge of the window.  If index is far out of view,
              then the procedure centers index in the window.

       (widget-name 'tag option ?arg arg ...?)
              This procedure is used to manipulate tags.  The exact behavior
              of the procedure depends on the option argument that follows the
              tag argument.  The following forms of the procedure are
              currently supported:

              (widget-name 'tag 'add tagName index1 ?index2 index1 index2
              ...?)
                     Associate the tag tagName with all of the characters
                     starting with index1 and ending just before index2 (the
                     character at index2 isn't tagged).  A single procedure
                     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
                     procedure has no effect.

              (widget-name 'tag 'bind tagName)

              (widget-name 'tag 'bind tagName sequence)

              (widget-name 'tag 'bind tagName sequence script)
                     This procedure 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 procedure is
                     similar to the bind procedure 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.  In this case the return
                     value is an empty string.  If script is omitted then the
                     procedure 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
                     procedure 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 procedure
                     for details).  continue and break procedures within
                     binding scripts are processed in the same way as for
                     bindings created with the bind procedure.

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

              (widget-name 'tag 'cget tagName option)
                     This procedure returns the current value of the option
                     named option associated with the tag given by tagName.
                     Option may have any of the values accepted by the tag
                     configure widget procedure.

              (widget-name 'tag 'configure tagName ?option? ?value? ?option
              value ...?)
                     This procedure is similar to the configure widget
                     procedure 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
                     procedure 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 procedure 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 procedure modifies the given
                     option(s) to have the given value(s) in tagName; in this
                     case the procedure returns an empty list.  See TAGS above
                     for details on the options available for tags.

              (widget-name 'tag 'delete tagName ?tagName ...?)
                     Deletes all tag information for each of the tagName
                     arguments.  The procedure 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 procedure returns an empty
                     list.

              (widget-name'tag 'lower tagName )

              (widget-name'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.

              (widget-name 'tag 'names )

              (widget-name '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 ``widget-name
                     tag'' widget procedure but haven't been deleted by a
                     ``widget-name tag delete'' widget procedure, even if no
                     characters are currently marked with the tag).  The list
                     will be sorted in order from lowest priority to highest
                     priority.

              (widget-name 'tag 'nextrange tagName index1 )

              (widget-name 'tag 'nextrange tagName index1  index2)
                     This procedure 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 procedure'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 list.  If index2 is not
                     given then it defaults to the end of the text.

              (widget-name 'tag 'prevrange tagName index1 )

              (widget-name '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.

              (widget-name'tag 'raise tagName )

              (widget-name'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.

              (widget-name '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 list is returned.

              (widget-name 'tag 'remove tagName index1 ?index2 index1 index2
              ...?)
                     Remove the tag tagName from all of the characters
                     starting at index1 and ending just before index2 (the
                     character at index2 isn't affected).  A single procedure
                     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
                     procedure has no effect.  This procedure returns an empty
                     list.

       (widget-name 'window option ?arg arg ...?)
              This procedure is used to manipulate embedded windows.  The
              behavior of the procedure depends on the option argument that
              follows the tag argument.  The following forms of the procedure
              are currently supported:

              (widget-name '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.

              (widget-name '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 procedure 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 procedure modifies the given
                     option(s) to have the given value(s);  in this case the
                     procedure returns an empty list.  See EMBEDDED WINDOWS
                     for information on the options that are supported.

              (widget-name 'window 'create index ?option value ...?)
                     This procedure 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 list.

              (widget-name 'window 'names)
                     Returns a list whose elements are the names of all
                     windows currently embedded in window.

       (widget-name 'xview option args)
              This procedure 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:

              (widget-name '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 :xscrollprocedure option.

              (widget-name '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.

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

       (widget-name 'yview ?args?)
              This procedure 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:

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

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

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

              (widget-name yview  index)

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

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

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

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

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

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

              (widget-name 'yview number)
                     This procedure 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 procedure 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'' refers
       to a contiguous group of letters, digits, or ``_'' characters, or any
       single character other than these.

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

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

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

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

       [14]   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.

       [15]   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.

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

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

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

       [19]   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.

       [20]   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.  If there is no selection in the widget then
              these keys have no effect.

       [21]   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.

       [22]   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.

       [23]   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.

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

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

       [26]   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.

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

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

       [29]   Control-x deletes whatever is selected in the text widget.

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

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

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


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

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

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

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



STk                                   3.1                              text(n)
