Provided by: perl-tk_804.036-1build1_amd64 bug

NAME

       Tk::Text - Create and manipulate Text widgets

SYNOPSIS

       $text = $parent->Text(?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

       Name:     height
       Class:    Height
       Switch:   -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.

       Name:     spacing1
       Class:    Spacing1
       Switch:   -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.

       Name:     spacing2
       Class:    Spacing2
       Switch:   -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.

       Name:     spacing3
       Class:    Spacing3
       Switch:   -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.

       Name:     state
       Class:    State
       Switch:   -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.

       Name:     tabs
       Class:    Tabs
       Switch:   -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 => [qw/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.

       Name:     width
       Class:    Width
       Switch:   -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.

       Name:     wrap
       Class:    Wrap
       Switch:   -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 method creates a new window (given by the $text 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, perl/Tk callbacks 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.

       The Perl/Tk Text widget does not support undo/redo, use the TextUndo widget instead.

INDICES

       Many of the methods for texts take one or more indices as arguments.  An index is a string
       used to indicate a particular place within a text, such as a place to insert characters or
       one endpoint of a range of characters to delete.  Indices have the syntax

        base modifier modifier modifier ...

       Where base gives a starting point and the modifiers adjust the index from the starting
       point (e.g. move forward or backward one character).  Every index must contain a base, but
       the modifiers are optional.

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

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

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

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

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

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

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

       $widget
           Indicates the position of the embedded window referenced by $widget.  This form
           generates an error if $widget does not reference to an embedded window.

       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 callbacks to it), it is given a
       priority higher than any existing tag.  The priority order of tags may be redefined using
       the ``$text->tagRaise'' and ``$text->tagLower'' methods.

       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 ``$text->tagConfigure'' method.  If a
       character has been tagged, then the display options associated with the tag override the
       default display style.  The following options are currently supported for tags:

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

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

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

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

       -data => value
           Allows an arbitrary perl scalar value to be associated with 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 -tabs = " ">, then
           it requests default 8-character tabs as described for the tabs 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 <perl/Tk callback|Tk::callbacks>
       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 tagBind widget method 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
       ``$text->mark'' text widget method, and their current locations may be determined by using
       the mark name as an index in methods.

       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 widgetCreate method, several
       configuration options may be associated with it.  These options may be  modified later
       with the widgetConfigure method.  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 => callback
           Specifies a callback that may be evaluated to create the window for the annotation.
           If no -window option has been specified for the annotation this callback will be
           evaluated when the annotation is about to be displayed on the screen.  Callback must
           create a window for the annotation and return the name of that window as its result.
           If the annotation's window should ever be deleted, callback 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 (see
           Tk_GetPixels).

       -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
           (see Tk_GetPixels).

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

EMBEDDED IMAGES

       The final form of annotation in text widgets is an embedded image.  Each embedded image
       annotation causes an image to be displayed at a particular point in  the text.  There may
       be any number of embedded images in a text widget, and a particular image may be embedded
       in multiple places in the same text widget.  The embedded image's position on the screen
       will be updated as the text is modified or scrolled.  Each embedded image occupies one
       character's worth of index space in the text widget, and it may be referred to either by
       its position in the widget's index space, or the name it is assigned when the image is
       inserted into the text widget with imageCreate.  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 method, 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 imageCreate method, several
       configuration options may be associated with it.  These options may be modified later with
       the image configure method.  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 ``$text->tagDelete'' method.  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
       ``$text->markUnset'' 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 programatically as well.  Whenever  the flag changes state a <<Modified>>
       virtual event is gener- ated. See the edit modified widget command for more details.

WIDGET METHODS

       The Text method creates a widget object.  This object supports the configure and cget
       methods described in Tk::options which can be used to enquire and modify the options
       described above.  The widget also inherits all the methods provided by the generic
       Tk::Widget class.

       The following additional methods are available for text widgets.  In addition, the
       extended text widget methods as documented in "Mastering Perl/Tk" are included in this pod
       (with permission from the publisher, O'Reilly and Associates Inc.).

       $text->adjustSelect
           Moves the end point of the selection and anchor point to the mouse pointer location.

       $text->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.

       $text->clipboardColumnCopy
           Performs a rectangular copy of the currently selected text with basic compensation for
           tab characters.

       $text->clipboardColumnCut
           Performs a rectangular cut of the currently selected text with basic compensation for
           tab characters.

       $text->clipboardColumnPaste
           Performs a rectangular paste of the text in the clipboard. The upper-left corner is
           specified by the current position of the insert mark with basic compensation for tab
           characters.

       $text->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.

       $text->Contents(?args?)
           Query or change the entire contents of the text widget. If no arguments are given, the
           entire contents of the text widget are returned. If any arguments are given, the
           entire contents of the text widget are deleted and replaced by the argument list.

       $text->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.

       $text->delete(index1, ?index2?)
           Delete a range of characters from the text.  If both index1 and index2 are specified,
           then delete all the characters starting with the one given by index1 and stopping just
           before index2 (i.e. the character at index2 is not deleted).  If index2 doesn't
           specify a position later in the text than index1 then no characters are deleted.  If
           index2 isn't specified then the single character at index1 is deleted.  It is not
           allowable to delete characters in a way that would leave the text without a newline as
           the last character.  The command returns an empty string.  If more indices are given,
           multiple ranges of text will be deleted.  All indices are first checked for  validity
           before any deletions are made.  They are sorted and the text is removed from the last
           range to the first range to deleted text does  not cause  a  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.

       $text->deleteSelected
           Delete the currently selected text.

       $text->deleteTextTaggedWith(tag)
           Delete the text tagged with the tag parameter.

       $text->deleteToEndofLine
           Delete from the insert mark location to the end of line.

       $text->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.

       $text->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 $text.  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 => callback
               Instead of returning the information as the result of the dump operation, invoke
               the callback on each element of the text widget within the range.  The callback
               has three arguments appended to it before it is evaluated: the 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.

       $text->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:

           $text->editModified( ?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.

           $text->editRedo;
               (Not implemented, use TextUndo.)  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.

           $text->editReset;
               (Not implemented, use TextUndo.) Clears the undo and redo stacks.

           $text->editSeparator;
               (Not implemented, use TextUndo.) Inserts a separator (boundary) on the undo stack.
               Does nothing when the -undo option is false.

           $text->editUndo;
               (Not implemented, use TextUndo.) 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.

       $text->FindAll(mode, case, pattern)
           Removes any current selections and then performs a global text search. All matches are
           tagged with the sel tag.

           mode can be be -exact or -regexp. See the search command for more information

           case can be -nocase or -case. See the search command for more information

           pattern is an exact string to match if mode is -exact or a regular expression if the
           match mode is -regexp.

       $text->FindAndReplaceAll(mode, case, find, replace)
           Same as the FindAll method, however additionally substitutes the matched text with the
           characters replace.

       $text->FindAndReplacePopUp
           Creates a find-and-replace popup window if one does not already exist.  If there is
           currently selected text, then the 'find' field will be 'pre-filled' with the
           selection.

       $text->FindNext(direction, mode, case, pattern)
           Removes any current selections and then performs a forward or reverse text search. All
           matches are tagged with the sel tag. direction can be -forwards or -backwards. mode,
           case and pattern are as for the FindAll method.

       $text->FindPopUp
           Creates a find popup, if one does not yet exist. If there is currently selected text,
           then the 'find' field will be 'pre-filled' with the selection.

       $text->FindSelectionNext
           Gets the currently selected text and removes all selections. It then finds the next
           exact, case-sensitive string that matches in a forward direction and selects the text
           and makes the new selection visible.

       $text->FindSelectionPrevious
           Gets the currently selected text and removes all selections. It then finds the next
           exact, case-sensitive string that matches in a reverse direction and selects the text
           and makes the new selection visible.

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

       $text->getSelected
           Return the currently selected text.

       $text->GetTextTaggedWith(tag)
           Return the text tagged with the tag parameter.

       $text->GotoLineNumber(line_number)
           Set the insert mark to line_number and ensures the line is visible.

       $text->GotoLineNumberPopUp(line_number)
           Displays a popup, pre-filling it with selected numeric text (if any), or the line
           number from GotoLineNumber (if any).

       $text->image(option, ?arg, arg, ...?)
       $text->imageOption(?arg, arg, ...?)
           This method is used to manipulate embedded images.  The behavior of the method depends
           on the option argument that follows the image prefix.  The following forms of the
           methods are currently supported:

           $text->imageCget(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 "EMBEDDED IMAGES".

           $text->imageConfigure(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::options 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.

           $text->imageCreate(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.

           $text->imageNames
                   Returns a list whose elements are the names of all image instances currently
                   embedded in $text.

       $text->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.

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

       $text->Insert(string)
           Do NOT confuse this with the lower-case insert method.  Insert string at the point of
           the insertion cursor. If there is a selection in the text, and it covers the point of
           the insertion cursor, then it deletes the selection before inserting.

       $text->InsertKeypress(character)
           Inserts character at the insert mark. If in overstrike mode, it firsts deletes the
           character at the insert mark.

       $text->InsertSelection
           Inserts the current selection at the insert mark.

       $text->insertTab
           Inserts a tab (\t) character at the insert mark.

       $text->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:

           $text->markGravity(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.

           $text->markNames
                   Returns a list whose elements are the names of all the marks that are
                   currently set.

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

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

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

           $text->markUnset(markName?, markName, markName, ...?)
                   Remove the mark corresponding to each of the markName arguments.  The removed
                   marks will not be usable in indices and will not be returned by future calls
                   to ``$text->markNames''.  This command returns an empty string.

       $text->markExists(markname)
           Returns true if markname exists - false otherwise.

       $text->menu(?menu?)
           If menu reference is given as an argument, then the text widget menu is adjusted to
           use this new menu. If the menu argument is undef, then this command disables the
           current text widget menu.  If the menu argument is omitted altogether, then the
           current text widget menu reference is returned.

       $text->openLine
           Inserts a newline (\n) at the insert mark.

       $text->OverstrikeMode(?boolean?)
           Returns the overstrike mode if boolean is omitted or sets the overstrike mode to
           boolean. True means overstrike mode is enabled.

       $text->PostPopupMenu(x,y)
           Creates a popup menu at the specified (x,y) pixel coordinates. The default menu has
           File, Edit, Search and View menu items which cascade to sub-menus for further
           commands. There is an implicit <Button-3> binding to this method that posts the menu
           over the cursor.

       $text->ResetAnchor
           Sets the selection anchor to whichever end is farthest from the index argument.

       $text->scan(option, args) or
       $text->scanoption(args)
           This method is used to implement scanning on texts.  It has two forms, depending on
           option:

           $text->scanMark(x, y)
                   Records x and y and the current view in the text window, for use in
                   conjunction with later scanDragto method.  Typically this method is associated
                   with a mouse button press in the widget.  It returns an empty string.

           $text->scanDragto(x, y)
                   This command computes the difference between its x and y arguments and the x
                   and y arguments to the last scanMark method 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.

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

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

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

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

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

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

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

           -hidden Find hidden text as well. By default only displayed text is found.

           --      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.

       $text->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.

       $text->selectAll
           Selects all the text in the widget.

       $text->selectLine
           Selects the line with the insert mark.

       $text->selectWord
           Selects the word with the insert mark.

       $text->SetCursor(position)
           Moves the insert mark to position.

       $text->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:

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

           $text->tagBind(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 method is similar to the bind
                   command except that it operates on characters in a text rather than entire
                   widgets.  See the Tk::bind documentation 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 the documentation 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.

           $text->tagCget(tagName, option)
                   This command returns the current value of the option named option associated
                   with the tag given by tagName.  Option may have any of the values accepted by
                   the tag configure method.

           $text->tagConfigure(tagName, ?option?, ?value?, ?option, value, ...?)
                   This command is similar to the configure method 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::options 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.

           $text->tagDelete(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.

           $text->tagLower(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.

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

           $text->tagNextrange(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.

           $text->tagPrevrange(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.

           $text->tagRaise(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.

           $text->tagRanges(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.

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

       $text->ToggleInsertMode
           Toggles the current overstrike mode.

       $text->unselectAll
           Unselects all the text in the widget.

       $text->WhatLineNumberPopup
           Creates a popup that displays the current line number of the insert mark.

       $text->widget(option?, arg, arg, ...?)
       $text->widgetOption(?arg, arg, ...?)
           This method is used to manipulate embedded windows.  The behavior of the method
           depends on the option argument that follows the window argument.  The following forms
           of the method are currently supported:

           $text->windowCget(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 "EMBEDDED
                   WINDOWS" above.

           $text->windowConfigure(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::options 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" above for information on the options
                   that are supported.

           $text->windowCreate(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" above for
                   information on the options that are supported.  Returns an empty string.

           $text->windowNames
                   Returns a list whose elements are the names of all windows currently embedded
                   in $text.

       $text->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:

           $text->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.

           $text->xviewMoveto(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.

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

       $text->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:

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

           $text->yviewMoveto(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.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

       [20]
           The F16 key (labelled Copy on many Sun workstations) or Meta-w copies the selection in
           the widget to the clipboard, if there is a selection.

       [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.  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.

       [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.

       [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.

TIED INTERFACE

       The Perl/Tk Text widget also has built-in TIEHANDLE methods for print and printf
       statements. This means you can print to file handles tied to a Text widget, and the tied
       methods automatically insert the print statement's arguments into the Text widget.

       For example:

        #!/usr/local/bin/perl -w
        use POSIX 'acos';
        use Tk;
        use strict;

        my $mw = MainWindow->new;
        my $text = $mw->Text(qw/-width 40 -height 10/)->pack;

        tie *STDOUT, ref $text, $text;

        print "Hello Text World!\n";
        printf "pi ~= %1.5f", acos(-1.0);

        MainLoop;

       To tie a scrolled Text widget, use the Subwidget method to get to the "real" widget:

        my $text = $mw->Scrolled('Text')->pack;
        tie *STDOUT, 'Tk::Text', $text->Subwidget('scrolled');

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 option to 0 avoid
       this.

SEE ALSO

       Tk::ROText Tk::TextUndo

KEYWORDS

       text, widget