# Tablelist Programmer's Guide

## For Tablelist Version 6.0

### by

## Csaba Nemethi

## Contents

#### Overview

- What Is Tablelist?
- How to Get It?
- How to Install It?
- How to Use It?
- More on Tablelist_tile

#### Examples

- A tablelist Widget for Displaying and Editing Configuration Options
- Two Widget Browsers Based on a tablelist
- A Directory Viewer Based on a tablelist
- Improving the Look & Feel of a tablelist Widget
- Advanced Interactive tablelist Cell Editing
- A tablelist Widget Containing Embedded Windows
- Tile-Based Demo Scripts

Start page

## Overview

### What Is Tablelist?

Tablelist is a library package for Tcl/Tk versions 8.0 or higher, written in pure Tcl/Tk code. It contains:

- the implementation of the tablelist mega-widget, including a general utility module for mega-widgets;
- a demo script containing a useful procedure that displays the configuration options of an arbitrary widget in a tablelist and enables you to edit their values interactively;
- a demo script implementing a widget browser based on a tablelist used as multi-column listbox;
- a demo script implementing a widget browser based on a tablelist used as multi-column tree widget;
- a demo script implementing a directory viewer based on a tablelist used as multi-column tree widget;
- a demo script showing several ways to improve the appearance of a tablelist widget;
- four further demo scripts, illustrating the interactive cell editing with the aid of various widgets from the Tk core and from the packages tile, BWidget, Iwidgets, combobox (by Bryan Oakley), and Mentry;
- one further demo script, with a tablelist widget containing embedded windows;
- tile-based counterparts of the above-mentioned demo scripts;
- this tutorial;
- reference pages in HTML format.

A tablelist is a multi-column listbox and tree widget. The width of each column can be dynamic (i.e., just large enough to hold all its elements, including the header) or static (specified in characters or pixels). The columns are, per default, resizable. The alignment of each column can be specified as `left`, `right`, or `center`.

The columns, rows, and cells can be configured individually. Several of the global and column-specific options refer to the header titles, implemented as label widgets. For instance, the `-labelcommand` option specifies a Tcl command to be invoked when mouse button 1 is released over a header label. The most common value of this option sorts the items based on the respective column.

The Tablelist package provides a great variety of tree styles controlling the look & feel of the column that displays the tree hierarchy with the aid of indentations and expand/collapse controls.

Interactive editing of the elements of a tablelist widget can be enabled for individual cells and for entire columns. A great variety of widgets from the Tk core and from the packages tile, BWidget, Iwidgets, combobox, ctext, and Mentry (or Mentry_tile) is supported for being used as embedded edit window. In addition, a rich set of keyboard bindings is provided for a comfortable navigation between the editable cells.

The Tcl command corresponding to a tablelist widget is very similar to the one associated with a normal listbox. There are column-, row-, and cell-specific counterparts of the `configure` and `cget` subcommands (`columnconfigure`, `rowconfigure`, `cellconfigure`, ...). They can be used, among others, to insert images into the cells and the header labels, or to insert embedded windows into the cells. The `index`, `nearest`, and `see` command options refer to the rows, but similar subcommands are provided for the columns and cells (`columnindex`, `cellindex`, ...). The items can be sorted with the `sort`, `sortbycolumn`, and `sortbycolumnlist` command options.

The bindings defined for the body of a tablelist widget make it behave just like a normal listbox. This includes the support for the virtual event `<<ListboxSelect>>` (which is equivalent to `<<TablelistSelect>>`). In addition, versions 2.3 or higher of the widget callback package Wcb (written in pure Tcl/Tk code as well) can be used to define callbacks for the `activate`, `selection set`, and `selection clear` commands, and Wcb versions 3.0 or higher also support callbacks for the `activatecell`, `cellselection set`, and `cellselection clear` commands. The download location of Wcb is

### How to Get It?

Tablelist is available for free download from the same URL as Wcb. The distribution file is `tablelist6.0.tar.gz` for UNIX and `tablelist6_0.zip` for Windows. These files contain the same information, except for the additional carriage return character preceding the linefeed at the end of each line in the text files for Windows.

Tablelist is also included in tklib, which has the address

### How to Install It?

Install the package as a subdirectory of one of the directories given by the `auto_path` variable. For example, you can install it as a directory at the same level as the Tcl and Tk script libraries. The locations of these library directories are given by the `tcl_library` and `tk_library` variables, respectively.

To install Tablelist on UNIX, `cd` to the desired directory and unpack the distribution file `tablelist6.0.tar.gz`:

>     gunzip -c tablelist6.0.tar.gz | tar -xf -

This command will create a directory named `tablelist6.0`, with the subdirectories `demos`, `doc`, and `scripts`.

On Windows, use WinZip or some other program capable of unpacking the distribution file `tablelist6_0ip` into the directory `tablelist6.0`, with the subdirectories `demos`, `doc`, and `scripts`.

The file `tablelistEdit.tcl` in the `scripts` directory is only needed for applications making use of interactive cell editing. Similarly, the file `tablelistMove.tcl` in the same directory is only required for scripts invoking the `move` or `movecolumn` command. Finally, the file `tablelistThemes.tcl` is only needed for applications using the package Tablelist_tile (see next section).

Next, you should check the exact version number of your Tcl/Tk distribution, given by the `tcl_patchLevel` and `tk_patchLevel` variables. If you are using Tcl/Tk version 8.2.X, 8.3.0 - 8.3.2, or 8.4a1, then you should upgrade your Tcl/Tk distribution to a higher release. This is because a bug in these Tcl versions (fixed in Tcl 8.3.3 and 8.4a2) causes excessive memory use when calling `info exists` on non-existent array elements, and Tablelist makes a lot of invocations of this command.

If for some reason you cannot upgrade your Tcl/Tk version, then you should execute the Tcl script `repair.tcl` in the directory `scripts`. This script makes backup copies of several files contained in this directory, and then creates new versions of them by replacing all invocations of `info exists` for array elements with a call to the helper procedure `arrElemExists`. The patched files work with all Tcl/Tk releases starting with 8.0, but the original ones have a much better performance.

Notice that in tklib the Tablelist `demos` directory is replaced with the subdirectory `tablelist` of the `examples` directory. Please take this into account when reading the examples below.

### How to Use It?

The Tablelist distribution provides two packages, called Tablelist and Tablelist_tile. The main difference between the two is that Tablelist_tile enables the tile-based, theme-specific appearance of tablelist widgets; this package requires Tcl/Tk 8.4 or higher and tile 0.6 or higher. It is not possible to use both packages in one and the same application, because both are implemented in the same `tablelist` namespace and provide identical commands.

To be able to access the commands and variables defined in the package Tablelist, your scripts must contain one of the lines

>     package require tablelist ?version?
>     package require Tablelist ?version?

You can use either one of the two statements above because the file `tablelist.tcl` contains both lines

>     package provide tablelist ...
>     package provide Tablelist ...

Likewise, to be able to access the commands and variables defined in the package Tablelist_tile, your scripts must contain one of the lines

>     package require tablelist_tile ?version?
>     package require Tablelist_tile ?version?

Again, you can use either one of the two statements above because the file `tablelist_tile.tcl` contains both lines

>     package provide tablelist_tile ...
>     package provide Tablelist_tile ...

You are free to remove one of the above lines from `tablelist.tcl` and `tablelist_tile.tcl`, respectively, if you want to prevent the corresponding packages from making themselves known under two different names each. Of course, by doing so you restrict the argument of `package require` to a single name per package.

Please note that ActiveTcl versions 8.5 and later use a modified package mechanism, which only exports the all-lowercase names `tablelist` and `tablelist_tile`.

REMARK: If you have an earlier Tablelist version as part of ActiveTcl 8.5 or above and the new Tablelist release 6.0, then it is highly recommended to specify the version number `6.0` in the `package require` command, because otherwise the interpreter will load the old Tablelist version included in ActiveTcl as Tcl Module. The examples below use the statement `package require tablelist 6.0`, and their tile-based counterparts invoke the command `package require tablelist_tile 6.0`.

Since the packages Tablelist and Tablelist_tile are implemented in the `tablelist` namespace, you must either invoke the

>     namespace import tablelist::pattern ?tablelist::pattern ...?

command to import the procedures you need, or use qualified names like `tablelist::tablelist`. In the examples below we have chosen the latter approach.

To access Tablelist variables, you must use qualified names. There are only 5 Tablelist variables (and one more when using Tablelist_tile) that are designed to be accessed outside the namespace `tablelist`:

- The variable `tablelist::version` holds the current version number of the Tablelist and Tablelist_tile packages.
- The variable `tablelist::library` holds the location of the Tablelist installation directory.
- The variable `tablelist::scalingpct` holds the scaling percentage used by Tablelist when adapting the sizes of the tree styles `vistaAero`, `vistaClassic`, `win7Aero`, `win7Classic`, and `win10` to the display's DPI scaling level. The currently supported values are `100`, `125`, `150`, and `200`. You can use the value of this variable, e.g., if you want to create images of different sizes, depending on the DPI scaling factor. For example, if your application uses images of size 16 x 16 on an unscaled display and `tablelist::scalingpct` has the value `150`, then the image size for this display should be 24 x 24.
- The boolean variable `tablelist::strictTk` (having the default value `0`) controls the strict listbox-compatibility of the default bindings.
- The read-only boolean variable `tablelist::usingTile` has the value `0` in the package Tablelist and the value `1` in Tablelist_tile.
- In Tablelist_tile the array `tablelist::themeDefaults` holds the theme-specific default values of a series of Tablelist configuration options.

### More on Tablelist_tile

A tablelist widget consists of a body (containing the items) and a header (displaying the column titles and optional header items). Both components are contained in a hull, implemented as a frame. The header has a rather complex structure, consisting, among others, of frame and label widgets. While in the Tablelist package all of these components are Tk widgets, the Tablelist_tile package uses both Tk and tile frame and label widgets. Due to several incompatibilities between Tk and tile, it is currently not possible to replace all Tk widgets making up a tablelist with their tile counterparts.

From the above it follows that the package Tablelist_tile will only work as expected if the Tk `frame` and `label` commands haven't been overridden by using `namespace import -force ttk::*` at global scope. While earlier tile releases suggested using this command at global scope for the really adventurous, in newer tile versions this is considered a Really Bad Idea, causing many things to break. Instead, you should explicitly invoke `ttk::frame`, `ttk::label`, etc. whenever you want to use a tile widget.

Overriding some other Tk widgets at global scope may be equally dangerous when using various widgets from the Tk core and from the packages BWidget, Iwidgets, combobox (by Bryan Oakley), ctext, and Mentry for interactive cell editing, because these packages expect Tk widgets, which may not always be replaced by their tile counterparts.

Another restriction to be taken into account is due to the fact that in earlier tile versions the `(ttk::)style theme use` command could only be used to set the current theme, but not to retrieve it. For this reason, the package Tablelist_tile makes use of the variable `ttk::currentTheme` or `tile::currentTheme` (depending on the tile version), which is set by the `ttk::setTheme` or `tile::setTheme` procedure. From this it follows that the tile-based tablelist widgets will only have the expected appearance if the platform-specific default theme is either left unchanged or replaced with another theme by invoking the procedure `ttk::setTheme` or `tile::setTheme`, depending on the current tile version. (See also the `tablelist::setTheme` command.)

After these cautions concerning the use of tile, the rest of this section describes the differences between the packages Tablelist and Tablelist_tile.

The Tablelist_tile package checks whether the required Tcl, Tk, and tile versions are present, by executing the commands

>     package require Tcl 8.4
>     package require Tk  8.4
>     if {$::tk_version < 8.5 || [regexp {^8\.5a[1-5]$} $::tk_patchLevel]} {
>         package require tile 0.6
>     }

The last command above reflects the fact that, beginning with Tk 8.5a6, tile is integrated into the Tk core and therefore it should only be loaded explicitly when using an earlier Tk version.

Apart from this and the `_tile` suffix in the `package require` command, the only difference (from the programmer's point of view) between the packages Tablelist and Tablelist_tile is related to the supported configuration options: The `-highlightbackground`, `-highlightcolor`, `-highlightthickness`, `-labelbackground`, `-labelactivebackground`, `-labelactiveforeground`, `-labeldisabledforeground`, and `-labelheight` options (the latter at both widget and column levels), present in the Tablelist package, are not supported by Tablelist_tile. The first three are standard Tk widget options that are not available for tile widgets. The `-labelbackground` option stands for the `-background` option of the column labels, and current versions of the tile engine don't support setting the background color for these widgets with a special header layout. The remaining options stand for the `-activebackground`, `-activeforeground`, `-disabledforeground`, and `-height` options of the column labels, and these configuration options are not supported for tile label widgets.

Also, take into account that in some themes, setting the `-labelborderwidth` option (at widget or column level) to a value other than the default might be ignored by tile and thus could cause alignment problems. This is because the border of tile widgets is drawn with theme-specific methods, which will not always produce the results known from Tk widgets.

Finally, notice that, when using the `tileqt` theme, the version number of the `tile::theme::tileqt` package must be 0.4 or higher, and `tileqt` itself won't work with tile versions earlier than 0.7.

Contents Start page

## Examples

### A tablelist Widget for Displaying and Editing Configuration Options

The file `config.tcl` in the `demos` directory contains a procedure `demo::displayConfig` that displays the configuration options of an arbitrary widget in a tablelist contained in a newly created top-level widget and allows you to edit these options. This procedure can prove to be quite useful during interactive GUI development. To test it, start `wish` and evaluate the file by using the `source` command as follows:

- If `wish` was started in the `demos` directory then it is sufficient to enter

  >     source config.tcl

- If `wish` was started in some other directory then you can use the `tablelist::library` variable to find the location of the file. For example, assuming that your Tablelist installation has the directory structure described in the How to install it? section, the required commands are:

  >     package require tablelist 6.0
  >     source [file join $tablelist::library demos config.tcl]

In both cases, the script will print the following message to `stdout`:

>     To display the configuration options of an arbitrary widget, enter

>             demo::displayConfig <widgetName>

`<widgetName>` can be the path name of any already existing widget. For example, if you enter

>     demo::displayConfig .

then you will see that a tablelist widget `.configTop.tf.tbl` in a new toplevel window is created and its name is printed to `stdout`. If you then enter

>     demo::displayConfig .configTop.tf.tbl

then another toplevel window containing the tablelist widget `.configTop2.tf.tbl` will pop up. The latter looks like in the following figure:

It is assumed that the Tcl command associated with the widget specified by `<widgetName>` has a `configure` subcommand which, when invoked without any argument, returns a list describing all of the available configuration options for the widget, in the common format known from the standard Tk widgets. The `demo::displayConfig` procedure inserts the items of this list into a scrolled tablelist with 5 dynamic-width columns and interactive sort capability, and returns the name of the newly created tablelist widget:

>     package require tablelist 6.0

>     namespace eval demo {
>         #
>         # Get the current windowing system ("x11", "win32", "classic", or "aqua")
>         # and add some entries to the Tk option database for the following
>         # widget hierarchy within a top-level widget of the class DemoTop:
>         #
>         # Name              Class
>         # -----------------------------
>         # tf                Frame
>         #   tbl               Tabellist
>         #   vsb, hsb          Scrollbar
>         # bf                Frame
>         #   b1, b2, b3        Button
>         #
>         variable winSys
>         if {[catch {tk windowingsystem} winSys] != 0} {
>             switch $::tcl_platform(platform) {
>                 unix        { set winSys x11 }
>                 windows     { set winSys win32 }
>                 macintosh   { set winSys classic }
>             }
>         }
>         if {[string compare $winSys "x11"] == 0} {
>             #
>             # Create the font TkDefaultFont if not yet present
>             #
>             catch {font create TkDefaultFont -family Helvetica -size -12}

>             option add *DemoTop*Font                        TkDefaultFont
>             option add *DemoTop*selectBackground            #5294e2
>             option add *DemoTop*selectForeground            white
>         }
>         option add *DemoTop.tf.borderWidth                  1
>         option add *DemoTop.tf.relief                       sunken
>         option add *DemoTop.tf.tbl.borderWidth              0
>         option add *DemoTop.tf.tbl.highlightThickness       0
>         option add *DemoTop.tf.tbl.background               white
>         option add *DemoTop.tf.tbl.stripeBackground         #f0f0f0
>         option add *DemoTop.tf.tbl.setGrid                  yes
>         option add *DemoTop.tf.tbl*Entry.background         white
>         option add *DemoTop.bf.Button.width                 10
>     }

>     #------------------------------------------------------------------------------
>     # demo::displayConfig
>     #
>     # Displays the configuration options of the widget w in a tablelist widget
>     # contained in a newly created top-level widget.  Returns the name of the
>     # tablelist widget.
>     #------------------------------------------------------------------------------
>     proc demo::displayConfig w {
>         if {![winfo exists $w]} {
>             bell
>             tk_messageBox -title "Error" -icon error -message \
>                 "Bad window path name \"$w\""
>             return ""
>         }

>         #
>         # Create a top-level widget of the class DemoTop
>         #
>         set top .configTop
>         for {set n 2} {[winfo exists $top]} {incr n} {
>             set top .configTop$n
>         }
>         toplevel $top -class DemoTop
>         wm title $top "Configuration Options of the [winfo class $w] Widget \"$w\""

>         #
>         # Create a scrolled tablelist widget with 5 dynamic-width
>         # columns and interactive sort capability within the top-level
>         #
>         set tf $top.tf
>         frame $tf
>         set tbl $tf.tbl
>         set vsb $tf.vsb
>         set hsb $tf.hsb
>         tablelist::tablelist $tbl \
>             -columns {0 "Command-Line Name"
>                       0 "Database/Alias Name"
>                       0 "Database Class"
>                       0 "Default Value"
>                       0 "Current Value"} \
>             -labelcommand tablelist::sortByColumn -sortcommand demo::compareAsSet \
>             -editendcommand demo::applyValue -height 15 -width 100 -stretch all \
>             -xscrollcommand [list $hsb set] -yscrollcommand [list $vsb set]
>         if {[$tbl cget -selectborderwidth] == 0} {
>             $tbl configure -spacing 1
>         }
>         $tbl columnconfigure 3 -maxwidth 30
>         $tbl columnconfigure 4 -maxwidth 30 -editable yes
>         scrollbar $vsb -orient vertical   -command [list $tbl yview]
>         scrollbar $hsb -orient horizontal -command [list $tbl xview]

>         #
>         # Create three buttons within a frame child of the top-level widget
>         #
>         set bf $top.bf
>         frame $bf
>         set b1 $bf.b1
>         set b2 $bf.b2
>         set b3 $bf.b3
>         button $b1 -text "Refresh"     -command [list demo::putConfig $w $tbl]
>         button $b2 -text "Sort as Set" -command [list $tbl sort]
>         button $b3 -text "Close"       -command [list destroy $top]

>         #
>         # Manage the widgets
>         #
>         grid $tbl -row 0 -rowspan 2 -column 0 -sticky news
>         variable winSys
>         if {[string compare $winSys "aqua"] == 0} {
>             grid [$tbl cornerpath] -row 0 -column 1 -sticky ew
>             grid $vsb              -row 1 -column 1 -sticky ns
>         } else {
>             grid $vsb -row 0 -rowspan 2 -column 1 -sticky ns
>         }
>         grid $hsb -row 2 -column 0 -sticky ew
>         grid rowconfigure    $tf 1 -weight 1
>         grid columnconfigure $tf 0 -weight 1
>         pack $b1 $b2 $b3 -side left -expand yes -pady 10
>         pack $bf -side bottom -fill x
>         pack $tf -side top -expand yes -fill both

>         #
>         # Populate the tablelist with the configuration options of the given widget
>         #
>         putConfig $w $tbl
>         return $tbl
>     }

The procedure invokes the `tablelist::tablelist` command to create a tablelist widget. The value of the `-columns` option passed to this command specifies the widths, titles, and alignments of the 5 columns. The width of each column is given as `0`, specifying that the column's width is to be made just large enough to hold all the elements in the column, including its title, which is the string following the width. We have omitted the alignment specifications (which can optionally follow the titles), because the columns shall all be left-justified.

Since all columns are of dynamic width and left-aligned, instead of `-columns` we could have used the `-columntitles` option as follows:

>         tablelist::tablelist $tbl \
>             -columntitles {"Command-Line Name"
>                            "Database/Alias Name"
>                            "Database Class"
>                            "Default Value"
>                            "Current Value"} \
>             . . .

The command `tablelist::sortByColumn`, specified as the value of the `-labelcommand` option, will be invoked whenever mouse button 1 is released over one of the labels. This command sorts the items based on the column corresponding to that label, in the right order, by invoking the `sortbycolumn` subcommand of the Tcl command associated with the tablelist widget.

As seen from the creation of the button displaying the text `"Sort as Set"`, the items will also be sorted by invoking the `sort` subcommand. This makes it necessary to specify a command to be used for the comparison of the items, as the value of the `-sortcommand` option. In our example this is the `demo::compareAsSet` procedure shown below.

The `-editendcommand` option specifies the command to be invoked automatically whenever the interactive editing of a cell's content is finished and the final content of the temporary embedded entry widget used for the editing are different from its original one. Per default, the elements of a tablelist widget can only be edited programmatically, but we enable the interactive editing for the cells of the last column with the aid of the `-editable` column configuration option.

By specifying the value `all` for the `-stretch` configuration option we make sure that all of the columns will be stretched to eliminate the blank space that might appear at the right of the table.

If the default value of the `-selectborderwidth` option is `0` (this is the case on the Windows and Macintosh platforms, and also in an X11 envronment with Tk 8.5 or above) then we use the `-spacing` option to provide some additional space above and below the rows.

For the last two columns of the tablelist we use the `-maxwidth` column configuration option, to make sure that the dynamic widths of these columns won't exceed 30 average-width characters.

Besides the options given on the command line, our tablelist widget will automatically inherit the ones contained in the Tk option database entries specified in the namespace initialization preceding the `demo::displayConfig` procedure. The database name `stripeBackground` corresponds to the `-stripebackground` configuration option. According to this entry, every other row of the tablelist widget will be displayed in the background color `#f0f0f0`, which improves the readability of the items and gives the widget a nice appearance.

The option database entries given for the windowing systems other than `x11` are implicitly used when managing the tablelist widget and the two scrollbars with the aid of `grid`. Notice how the `cornerpath` subcommand enables us to achieve a native look & feel with respect to the vertical scrollbar on the windowing system `aqua`.

We populate the tablelist by invoking the `demo::putConfig` procedure discussed below. The same script is associated with the Refresh button, as the value of its `-command` configuration option. This procedure is implemented as follows:

>     #------------------------------------------------------------------------------
>     # demo::putConfig
>     #
>     # Outputs the configuration options of the widget w into the tablelist widget
>     # tbl.
>     #------------------------------------------------------------------------------
>     proc demo::putConfig {w tbl} {
>         if {![winfo exists $w]} {
>             bell
>             tk_messageBox -title "Error" -icon error -message \
>                 "Bad window path name \"$w\"" -parent [winfo toplevel $tbl]
>             return ""
>         }

>         #
>         # Display the configuration options of w in the tablelist widget tbl
>         #
>         $tbl delete 0 end
>         foreach configSet [$w configure] {
>             #
>             # Insert the list configSet into the tablelist widget
>             #
>             $tbl insert end $configSet

>             if {[llength $configSet] == 2} {
>                 $tbl rowconfigure end -foreground gray50 -selectforeground gray75
>                 $tbl cellconfigure end -editable no
>             } else {
>                 #
>                 # Change the colors of the first and last cell of the row
>                 # if the current value is different from the default one
>                 #
>                 set default [lindex $configSet 3]
>                 set current [lindex $configSet 4]
>                 if {[string compare $default $current] != 0} {
>                     foreach col {0 4} {
>                         $tbl cellconfigure end,$col \
>                              -foreground red -selectforeground yellow
>                     }
>                 }
>             }
>         }

>         $tbl sortbycolumn 0
>         $tbl activate 0
>         $tbl attrib widget $w
>     }

After deleting the current items of the tablelist widget `tbl`, the procedure inserts the items of the list returned by the `configure` subcommand of the Tcl command associated with the widget `w`. For each option that is merely an abbreviated form of some other one, we use the `rowconfigure` tablelist subcommand to change the normal and selection foreground colors of the item just appended, and we disable the interactive editing in the last inserted cell by using the `-editable` cell configuration option. The `cellconfigure` tablelist operation is also invoked for each real option whose current value is different from the default one, to change the values of the `-foreground` and `-selectforeground` options of the cells no. 0 and 4, containing the command-line name of the option and its current value.

Each tablelist widget may have any number of private attributes, which can be set and retrieved with the aid of the `attrib` subcommand of the Tcl command corresponding to the widget. The `demo::putConfig` procedure sets the `widget` attribute to the name of the widget whose options are displayed in the tablelist.

The implementation of the comparison command `demo::compareAsSet` mentioned above is quite simple:

>     #------------------------------------------------------------------------------
>     # demo::compareAsSet
>     #
>     # Compares two items of a tablelist widget used to display the configuration
>     # options of an arbitrary widget.  The item in which the current value is
>     # different from the default one is considered to be less than the other; if
>     # both items fulfil this condition or its negation then string comparison is
>     # applied to the two option names.
>     #------------------------------------------------------------------------------
>     proc demo::compareAsSet {item1 item2} {
>         foreach {opt1 dbName1 dbClass1 default1 current1} $item1 \
>                 {opt2 dbName2 dbClass2 default2 current2} $item2 {
>             set changed1 [expr {[string compare $default1 $current1] != 0}]
>             set changed2 [expr {[string compare $default2 $current2] != 0}]
>             if {$changed1 == $changed2} {
>                 return [string compare $opt1 $opt2]
>             } elseif {$changed1} {
>                 return -1
>             } else {
>                 return 1
>             }
>         }
>     }

Finally, here is the implementation of the `demo::applyValue` procedure, specified as the value of the `-editendcommand` option:

>     #------------------------------------------------------------------------------
>     # demo::applyValue
>     #
>     # Applies the new value of the configuraton option contained in the given row
>     # of the tablelist widget tbl to the widget whose options are displayed in it,
>     # and updates the colors of the first and last cell of the row.
>     #------------------------------------------------------------------------------
>     proc demo::applyValue {tbl row col text} {
>         #
>         # Try to apply the new value of the option contained in
>         # the given row to the widget whose options are displayed
>         # in the tablelist; reject the value if the attempt fails
>         #
>         set w [$tbl attrib widget]
>         set opt [$tbl cellcget $row,0 -text]
>         if {[catch {$w configure $opt $text} result] != 0} {
>             bell
>             tk_messageBox -title "Error" -icon error -message $result \
>                 -parent [winfo toplevel $tbl]
>             $tbl rejectinput
>             return ""
>         }

>         #
>         # Replace the new option value with its canonical form and
>         # update the colors of the first and last cell of the row
>         #
>         set text [$w cget $opt]
>         set default [$tbl cellcget $row,3 -text]
>         if {[string compare $default $text] == 0} {
>             foreach col {0 4} {
>                 $tbl cellconfigure $row,$col \
>                      -foreground "" -selectforeground ""
>             }
>         } else {
>             foreach col {0 4} {
>                 $tbl cellconfigure $row,$col \
>                      -foreground red -selectforeground yellow
>             }
>         }

>         return $text
>     }

The procedure retrieves the name of the widget whose options are displayed in the tablelist, as the value of its `widget` attribute, and invokes the `cellcget` tablelist subcommand to get the name of the option specified in the first cell of the row whose last element was just edited. Next, it tries to apply the new value of the option to the widget, and invokes the `rejectinput` subcommand if the attempt fails. Otherwise it replaces the new option value with its canonical form and updates the normal and selection foreground colors of the cells no. 0 and 4. The canonical form of the option value is given by the `cget` subcommand of the Tcl command associated with that widget. For example, a boolean value will always be replaced with `1` or `0`, even if the entry contains the string `yes` or `no`. The procedure returns this canonical option value, thus making sure that the latter will become the new content of the cell that was just edited.

### Two Widget Browsers Based on a tablelist

The files `browse.tcl` and `browseTree.tcl` in the `demos` directory contain a procedure `demo::displayChildren` that displays information about the children of an arbitrary widget in a tablelist contained in a newly created top-level widget. To test it, start `wish` and evaluate the chosen file by using the `source` command, in a similar way as in the case of the previous example.

Both scripts will print the following message to `stdout`:

>     To display information about the children of an arbitrary widget, enter

>             demo::displayChildren <widgetName>

`<widgetName>` can be the path name of any already existing widget. For example, if you enter

>     demo::displayChildren .

then you will see that a tablelist widget `.browseTop.tf.tbl` in a new toplevel window is created and its name is printed to `stdout`.

The tablelist created by the procedure `demo::displayChildren` in the file `browse.tcl` is a multi-column listbox:

The tablelist created by the procedure of the same name in the file `browseTree.tcl` is a multi-column tree widget:

The `demo::displayChildren` command inserts some data of the children of the widget specified by `<widgetName>` into a vertically scrolled tablelist with 9 dynamic-width columns and interactive sort capability, and returns the name of the newly created tablelist widget. By double-clicking an item (e.g., the one containing the path name `.browseTop` in `browse.tcl` and the name `browseTop` in `browseTree.tcl`) or invoking the first entry of a pop-up menu within the body of the tablelist, you can display the data of the children of the widget corresponding to the selected item, and with the second menu entry you can display its configuration options (see the previous example for details). To go one level up, click on the Parent button.

There is a lot of code common to the scripts `browse.tcl` and `browseTree.tcl`. We will restrict the description below to the second one, which requires Tk 8.3 or later, due to the use of several tree-related tablelist options and subcommands.

>     package require Tk 8.3
>     package require tablelist 6.0

>     namespace eval demo {
>         variable dir [file dirname [info script]]

>         #
>         # Create two images, needed in the procedure putChildren
>         #
>         variable leafImg [image create bitmap -file [file join $dir leaf.xbm] \
>                           -background coral -foreground gray50]
>         variable compImg [image create bitmap -file [file join $dir comp.xbm] \
>                           -background yellow -foreground gray50]
>     }

>     source [file join $demo::dir config.tcl]

>     #------------------------------------------------------------------------------
>     # demo::displayChildren
>     #
>     # Displays information on the children of the widget w in a tablelist widget
>     # contained in a newly created top-level widget.  Returns the name of the
>     # tablelist widget.
>     #------------------------------------------------------------------------------
>     proc demo::displayChildren w {
>         if {![winfo exists $w]} {
>             bell
>             tk_messageBox -title "Error" -icon error -message \
>                 "Bad window path name \"$w\""
>             return ""
>         }

>         #
>         # Create a top-level widget of the class DemoTop
>         #
>         set top .browseTop
>         for {set n 2} {[winfo exists $top]} {incr n} {
>             set top .browseTop$n
>         }
>         toplevel $top -class DemoTop

>         #
>         # Create a vertically scrolled tablelist widget with 9 dynamic-width
>         # columns and interactive sort capability within the top-level
>         #
>         set tf $top.tf
>         frame $tf
>         set tbl $tf.tbl
>         set vsb $tf.vsb
>         tablelist::tablelist $tbl \
>             -columns {0 "Name"      left
>                       0 "Class"     left
>                       0 "X"         right
>                       0 "Y"         right
>                       0 "Width"     right
>                       0 "Height"    right
>                       0 "Mapped"    center
>                       0 "Viewable"  center
>                       0 "Manager"   left} \
>             -expandcommand demo::expandCmd -labelcommand demo::labelCmd \
>             -yscrollcommand [list $vsb set] -setgrid no -width 0
>         if {[$tbl cget -selectborderwidth] == 0} {
>             $tbl configure -spacing 1
>         }
>         foreach col {2 3 4 5} {
>             $tbl columnconfigure $col -sortmode integer
>         }
>         foreach col {6 7} {
>             $tbl columnconfigure $col -formatcommand demo::formatBoolean
>         }
>         scrollbar $vsb -orient vertical -command [list $tbl yview]

>         #
>         # When displaying the information about the children of any
>         # ancestor of the label widgets, the widths of some of the
>         # labels and thus also the widths and x coordinates of some
>         # children may change.  For this reason, make sure the items
>         # will be updated after any change in the sizes of the labels
>         #
>         foreach l [$tbl labels] {
>             bind $l <Configure> [list demo::updateItemsDelayed $tbl]
>         }
>         bind $tbl <Configure> [list demo::updateItemsDelayed $tbl]

>         #
>         # Create a pop-up menu with two command entries; bind the script
>         # associated with its first entry to the <Double-1> event, too
>         #
>         set menu $top.menu
>         menu $menu -tearoff no
>         $menu add command -label "Display Children" \
>                           -command [list demo::putChildrenOfSelWidget $tbl]
>         $menu add command -label "Display Config" \
>                           -command [list demo::dispConfigOfSelWidget $tbl]
>         set bodyTag [$tbl bodytag]
>         bind $bodyTag <Double-1>   [list demo::putChildrenOfSelWidget $tbl]
>         bind $bodyTag <<Button3>>  [bind TablelistBody <Button-1>]
>         bind $bodyTag <<Button3>> +[bind TablelistBody <ButtonRelease-1>]
>         bind $bodyTag <<Button3>> +[list demo::postPopupMenu $top %X %Y]

>         #
>         # Create three buttons within a frame child of the top-level widget
>         #
>         set bf $top.bf
>         frame $bf
>         set b1 $bf.b1
>         set b2 $bf.b2
>         set b3 $bf.b3
>         button $b1 -text "Refresh"
>         button $b2 -text "Parent"
>         button $b3 -text "Close" -command [list destroy $top]

>         #
>         # Manage the widgets
>         #
>         . . .

>         #
>         # Populate the tablelist with the data of the given widget's children
>         #
>         putChildren $w $tbl root
>         return $tbl
>     }

The procedure invokes the `tablelist::tablelist` command to create a tablelist widget. The value of the `-columns` option passed to this command specifies the widths, titles, and alignments of the 9 columns. The width of each column is given as `0`, specifying that the column's width is to be made just large enough to hold all the elements in the column, including its title, which is the string following the width. Each of the titles is followed by an alignment, which indicates how to justify both the elements and the title of the respective column.

We want to display not only the data of the given widget's children, but also those of its further descendants. To this end, we need a command to be invoked whenever an item corresponding to a widget with children gets expanded. This command is specified as the value of the `-expandcommand` option. As discussed later, the `demo::expandCmd` procedure will insert the children of the row that is about to be expanded, if it has no children yet.

The command `demo::labelCmd`, specified as the value of the `-labelcommand` option, will be invoked whenever mouse button 1 is released over one of the labels. We will discuss this procedure later.

We specify the value `0` for the widget's `-width` option, meaning that the tablelist's width shall be made just large enough to hold all its columns.

After creating the tablelist widget, we make sure that the elements of its columns 2, 3, 4, and 5 (displaying the x and y coordinates as well as the widths and heights of the children) will be compared as integers when sorting the items based on one of these columns. We do this with the aid of the `columnconfigure` tablelist operation.

The same `columnconfigure` subcommand enables us to specify that, when displaying the elements of columns 6 and 7 (having the titles `"Mapped"` and `"Viewable"`, respectively), the boolean values `1` and `0` will be replaced with the strings `"yes"` and `"no"`, returned by the `demo::formatBoolean` command shown below.

After creating the vertical scrollbar, we iterate over the elements of the list containing the path names of all header labels of the tablelist widget, returned by the `labels` subcommand of the Tcl command corresponding to the widget. For each element of the list, we bind the procedure `demo::updateItemsDelayed` to the `<Configure>` event. In this way we make sure the procedure will be invoked whenever the header label indicated by that list element changes size.

The four invocations of the `bind` command following the creation of the pop-up menu make use of a binding tag whose name depends on the path name of the tablelist widget and is returned by the `bodytag` subcommand of the Tcl command associated with the tablelist widget. The advantage of using this tag instead of the path name of the tablelist's body is that this binding tag is associated not only with the body but also with the separator frames and with the labels displaying embedded images. This is important in our example because we want to make sure the `<<Button3>>` and `<Double-1>` events will be handled in the same way within a label containing an embedded image as in the rest of the tablelist's body. Both the `<<Button3>>` virtual event (used in the first three `bind` commands) and the `TablelistBody` binding tag (used in the first binding script) are created by the Tablelist package. The first three `bind` commands make sure that a `<<Button3>>` virtual event will select and activate the nearest item and will post a pop-up menu with two command entries that refer to the widget described by that item.

We populate the tablelist by invoking the `demo::putChildren` procedure, implemented as follows:

>     #------------------------------------------------------------------------------
>     # demo::putChildren
>     #
>     # Outputs the data of the children of the widget w into the tablelist widget
>     # tbl, as child items of the one identified by nodeIdx.
>     #------------------------------------------------------------------------------
>     proc demo::putChildren {w tbl nodeIdx} {
>         . . .

>         if {[string compare $nodeIdx "root"] == 0} {
>             set top [winfo toplevel $tbl]
>             wm title $top "Children of the [winfo class $w] Widget \"$w\""

>             $tbl resetsortinfo
>             $tbl delete 0 end
>             set row 0
>         } else {
>             set row [expr {$nodeIdx + 1}]
>         }

>         #
>         # Display the data of the children of the
>         # widget w in the tablelist widget tbl
>         #
>         variable leafImg
>         variable compImg
>         foreach c [winfo children $w] {
>             #
>             # Insert the data of the current child into the tablelist widget
>             #
>             set item {}
>             lappend item \
>                     [winfo name $c] [winfo class $c] [winfo x $c] [winfo y $c] \
>                     [winfo width $c] [winfo height $c] [winfo ismapped $c] \
>                     [winfo viewable $c] [winfo manager $c]
>             $tbl insertchild $nodeIdx end $item

>             #
>             # Insert an image into the first cell of the row; mark the
>             # row as collapsed if the child widget has children itself
>             #
>             if {[llength [winfo children $c]] == 0} {
>                 $tbl cellconfigure end,0 -image $leafImg
>             } else {
>                 $tbl cellconfigure end,0 -image $compImg
>                 $tbl collapse $row
>             }

>             $tbl rowattrib $row pathName $c
>             incr row
>         }

>         if {[string compare $nodeIdx "root"] == 0} {
>             #
>             # Configure the "Refresh" and "Parent" buttons
>             #
>             $top.bf.b1 configure -command [list demo::refreshView $w $tbl]
>             set b2 $top.bf.b2
>             set p [winfo parent $w]
>             if {[string compare $p ""] == 0} {
>                 $b2 configure -state disabled
>             } else {
>                 $b2 configure -state normal -command \
>                     [list demo::putChildren $p $tbl root]
>             }
>         }
>     }

The last argument of this procedure indicates the tree node to become the parent of the items displaying the data of the children of the widget passed as first argument. If this parent is the invisible `root` node then we first reset the sorting information by invoking the `resetsortinfo` tablelist subcommand and delete the current items of the tablelist widget `tbl`. The procedure then iterates over the children of the specified widget and inserts the items built from some data retrieved by using the `winfo` command. Each new item is added to the end of the parent node's list of children with the aid of the `insertchild(ren)` subcommand.

For each child widget, we invoke the `cellconfigure` tablelist operation to set the value of the `-image` option of the corresponding row's first cell, containing the leaf name of the child. In this way, the procedure inserts the image `$leafImg` or `$compImg` into the first cell, depending on whether the child in question is a leaf or a composite widget. (Remember that both images were created outside this procedure, within the initialization of the `demo` namespace.)

We mark every newly created row corresponding to a child widget that has children itself as collapsed by invoking the `collapse` subcommand. This will prepend an expand/collapse control to the content of the first column, whose column index `0` is the default value of the `-treecolumn` configuration option.

We use the `rowattrib` tablelist subcommand to remember the full path name of every child widget as a private attribute associated with the corresponding tablelist row, because it will be needed at several places later on.

As mentioned above, the `demo::expandCmd` procedure will be invoked automatically when expanding a row that contains an expand/collapse control:

>     ------------------------------------------------------------------------------
>     # demo::expandCmd
>     #
>     # Outputs the data of the children of the widget whose leaf name is displayed
>     # in the first cell of the specified row of the tablelist widget tbl, as child
>     # items of the one identified by row.
>     #------------------------------------------------------------------------------
>     proc demo::expandCmd {tbl row} {
>         if {[$tbl childcount $row] == 0} {
>             set w [$tbl rowattrib $row pathName]
>             putChildren $w $tbl $row

>             #
>             # Apply the last sorting (if any) to the new items
>             #
>             $tbl refreshsorting $row
>         }
>     }

The procedure invokes the `childcount` subcommand to check whether the children of the row that is about to be expanded have already been inserted into the tablelist widget, and inserts them if this is not the case. It also makes sure that the child items will be displayed in the order corresponding to the last sorting (if any), with the aid of the `refreshsorting` tablelist subcommand. Any sorting (if needed) will only be performed on the child items just inserted into the tablelist widget.

The `demo::formatBoolean` and `demo::labelCmd` procedures mentioned above are trivial:

>     #------------------------------------------------------------------------------
>     # demo::formatBoolean
>     #
>     # Returns "yes" or "no", according to the specified boolean value.
>     #------------------------------------------------------------------------------
>     proc demo::formatBoolean val {
>         return [expr {$val ? "yes" : "no"}]
>     }

>     #------------------------------------------------------------------------------
>     # demo::labelCmd
>     #
>     # Sorts the content of the tablelist widget tbl by its col'th column and makes
>     # sure the items will be updated 500 ms later (because one of the items might
>     # refer to a canvas containing the arrow that displays the sorting order).
>     #------------------------------------------------------------------------------
>     proc demo::labelCmd {tbl col} {
>         tablelist::sortByColumn $tbl $col
>         updateItemsDelayed $tbl
>     }

The command `tablelist::sortByColumn` sorts the items of the tablelist widget by the specified column in the right order, by invoking the `sortbycolumn` subcommand of the Tcl command associated with the tablelist widget.

The implementation of the `demo::updateItemsDelayed` command, invoked in this procedure and already encountered in the `demo::displayChildren` procedure above, is quite simple:

>     #------------------------------------------------------------------------------
>     # demo::updateItemsDelayed
>     #
>     # Arranges for the items of the tablelist widget tbl to be updated 500 ms later.
>     #------------------------------------------------------------------------------
>     proc demo::updateItemsDelayed tbl {
>         #
>         # Schedule the demo::updateItems command for execution
>         # 500 ms later, but only if it is not yet pending
>         #
>         if {[string compare [$tbl attrib afterId] ""] == 0} {
>             $tbl attrib afterId [after 500 [list demo::updateItems $tbl]]
>         }
>     }

>     #------------------------------------------------------------------------------
>     # demo::updateItems
>     #
>     # Updates the items of the tablelist widget tbl.
>     #------------------------------------------------------------------------------
>     proc demo::updateItems tbl {
>         #
>         # Reset the tablelist's "afterId" attribute
>         #
>         $tbl attrib afterId ""

>         #
>         # Update the items
>         #
>         set rowCount [$tbl size]
>         for {set row 0} {$row < $rowCount} {incr row} {
>             set c [$tbl cellcget $row,0 -text]
>             if {![winfo exists $c]} {
>                 continue
>             }

>             set item {}
>             lappend item \
>                     [winfo name $c] [winfo class $c] [winfo x $c] [winfo y $c] \
>                     [winfo width $c] [winfo height $c] [winfo ismapped $c] \
>                     [winfo viewable $c] [winfo manager $c]
>             $tbl rowconfigure $row -text $item
>         }

>         #
>         # Repeat the last sort operation (if any)
>         #
>         $tbl refreshsorting
>     }

As already mentioned in the previous example, each tablelist widget may have any number of private attributes, which can be set and retrieved with the aid of the `attrib` subcommand of the Tcl command corresponding to the widget. The `afterId` attribute is set by the `demo::updateItemsDelayed` procedure when sheduling the `demo::updateItems` command for execution 500 ms later, but only if its value is an empty string. For this reason, the `demo::updateItems` procedure resets this attribute. It also makes use of the `cellcget` tablelist subcommand to get the path names contained in the first cell of each row, and updates the data of the children with the aid of the `rowconfigure` subcommand. After updating the items, the procedure repeats the most recent sorting based on a column (if there was one), with the aid of the `refreshsorting` subcommand.

The procedures `demo::putChildrenOfSelWidget`, `demo::dispConfigOfSelWidget`, and `demo::postPopupMenu` (see `demo::displayChildren`) are also straight-forward. For example, the `demo::putChildrenOfSelWidget` command shown below makes use of the `curselection` subcommand to get the index of the selected row. More precisely, `curselection` returns a list, but in our case this list will have exactly one element, hence it can be used directly as the first component of a cell index.

>     #------------------------------------------------------------------------------
>     # demo::putChildrenOfSelWidget
>     #
>     # Outputs the data of the children of the selected widget into the tablelist
>     # widget tbl.
>     #------------------------------------------------------------------------------
>     proc demo::putChildrenOfSelWidget tbl {
>         set w [$tbl cellcget [$tbl curselection],0 -text]
>         if {![winfo exists $w]} {
>             bell
>             tk_messageBox -title "Error" -icon error -message \
>                 "Bad window path name \"$w\"" -parent [winfo toplevel $tbl]
>             return ""
>         }

>         if {[llength [winfo children $w]] == 0} {
>             bell
>         } else {
>             putChildren $w $tbl
>         }
>     }

The procedure `demo::refreshView`, associated with the Refresh button, is implemented as follows:

>     #------------------------------------------------------------------------------
>     # demo::refreshView
>     #
>     # Redisplays the data of the children of the widget w in the tablelist widget
>     # tbl and restores the expanded states of the items as well as the vertical
>     # view.
>     #------------------------------------------------------------------------------
>     proc demo::refreshView {w tbl} {
>         #
>         # Save the vertical view and get the path names of
>         # the child widgets displayed in the expanded rows
>         #
>         set yView [$tbl yview]
>         foreach key [$tbl expandedkeys] {
>             set pathName [$tbl rowattrib $key pathName]
>             set expandedWidgets($pathName) 1
>         }

>         #
>         # Redisplay the data of the widget's (possibly changed) children and
>         # restore the expanded states of the children, along with the vertical view
>         #
>         putChildren $w $tbl root
>         restoreExpandedStates $tbl root expandedWidgets
>         $tbl yview moveto [lindex $yView 0]
>     }

Before redisplaying the tablelist's content via `demo::putChildren`, we get the full keys of the currently expanded items with the aid of the `expandedkeys` tablelist subcommand and insert the correspondig widget paths into the array `expandedWidgets`. After redisplaying the data of the (possibly changed) children of the widget given as first argument, we pass this array to the `demo::restoreExpandedStates` procedure shown below:

>     #------------------------------------------------------------------------------
>     # restoreExpandedStates
>     #
>     # Expands those children of the parent identified by nodeIdx that display the
>     # data of child widgets whose path names are the names of the elements of the
>     # array specified by the last argument.
>     #------------------------------------------------------------------------------
>     proc demo::restoreExpandedStates {tbl nodeIdx expandedWidgetsName} {
>         upvar $expandedWidgetsName expandedWidgets

>         foreach key [$tbl childkeys $nodeIdx] {
>             set pathName [$tbl rowattrib $key pathName]
>             if {[info exists expandedWidgets($pathName)]} {
>                 $tbl expand $key -partly
>                 restoreExpandedStates $tbl $key expandedWidgets
>             }
>         }
>     }

The procedure retrieves the list of full keys of the children of the parent node indicated by `nodeIdx`, by means of the `childkeys` tablelist subcommand. It then loops over this list, and for each key for which the corresponding row was previously expanded, it invokes the `expand` tablelist subcommand and then calls itself recursively to restore the expanded states of that row's children.

### A Directory Viewer Based on a tablelist

The script `dirViewer.tcl` in the `demos` directory displays the contents of the volumes mounted on the system (e.g., the root `/` on UNIX and the local drives on Windows) in a tablelist used as multi-column tree widget:

By double-clicking an item or invoking the single entry of a pop-up menu within the body of the tablelist, you can display the content of the folder corresponding to the selected item. To go one level up, click on the Parent button.

There are a lot of similarities between this script and the one discussed in the previous section. In the following we will only present a few procedures that invoke tablelist commands not encountered in the examples above:

>     package require Tk 8.3
>     package require tablelist 6.0

>     #
>     # Add some entries to the Tk option database
>     #
>     set dir [file dirname [info script]]
>     source [file join $dir option.tcl]

>     #
>     # Create three images
>     #
>     image create photo clsdFolderImg -file [file join $dir clsdFolder.gif]
>     image create photo openFolderImg -file [file join $dir openFolder.gif]
>     image create photo fileImg       -file [file join $dir file.gif]

>     #------------------------------------------------------------------------------
>     # displayContents
>     #
>     # Displays the content of the directory dir in a tablelist widget.
>     #------------------------------------------------------------------------------
>     proc displayContents dir {
>         #
>         # Create a scrolled tablelist widget with 3 dynamic-
>         # width columns and interactive sort capability
>         #
>         set tf .tf
>         frame $tf -class ScrollArea
>         set tbl $tf.tbl
>         set vsb $tf.vsb
>         set hsb $tf.hsb
>         tablelist::tablelist $tbl \
>             -columns {0 "Name"          left
>                       0 "Size"          right
>                       0 "Date Modified" left} \
>             -expandcommand expandCmd -collapsecommand collapseCmd \
>             -xscrollcommand [list $hsb set] -yscrollcommand [list $vsb set] \
>             -movablecolumns no -setgrid no -showseparators yes -height 20 -width 80
>         if {[$tbl cget -selectborderwidth] == 0} {
>             $tbl configure -spacing 1
>         }
>         $tbl columnconfigure 0 -formatcommand formatString -sortmode dictionary
>         $tbl columnconfigure 1 -formatcommand formatSize -sortmode integer
>         $tbl columnconfigure 2 -formatcommand formatString
>         scrollbar $vsb -orient vertical   -command [list $tbl yview]
>         scrollbar $hsb -orient horizontal -command [list $tbl xview]

>         . . .

>         #
>         # Populate the tablelist with the content of the given directory
>         #
>         $tbl sortbycolumn 0
>         putContents $dir $tbl root
>     }

The procedure `displayContents` creates the tablelist widget and the two scrollbars as children of a frame of class `ScrollArea`. For this class, the file `option.tcl`, `source`d into the main script, contains some look & feel related settings similar to the ones encountered in our first example:

>     option add *ScrollArea.borderWidth                      1
>     option add *ScrollArea.relief                           sunken
>     option add *ScrollArea.Tablelist.borderWidth            0
>     option add *ScrollArea.Tablelist.highlightThickness     0

The procedure specifies a value not only for the `-expandcommand` option of the tablelist it creates, but also for its `-collapsecommand` option. The latter will merely restore the image shown in the first column to the one displaying a closed folder (see below).

>     #------------------------------------------------------------------------------
>     # putContents
>     #
>     # Outputs the content of the directory dir into the tablelist widget tbl, as
>     # child items of the one identified by nodeIdx.
>     #------------------------------------------------------------------------------
>     proc putContents {dir tbl nodeIdx} {
>         . . .

>         if {[string compare $nodeIdx "root"] == 0} {
>             if {[string compare $dir ""] == 0} {
>                 if {[llength [file volumes]] == 1} {
>                     wm title . "Contents of the File System"
>                 } else {
>                     wm title . "Contents of the File Systems"
>                 }
>             } else {
>                 wm title . "Contents of the Directory \"[file nativename $dir]\""
>             }

>             $tbl delete 0 end
>             set row 0
>         } else {
>             set row [expr {$nodeIdx + 1}]
>         }

>         #
>         # Build a list from the data of the subdirectories and
>         # files of the directory dir.  Prepend a "D" or "F" to
>         # each entry's name and modification date & time, for
>         # sorting purposes (it will be removed by formatString).
>         #
>         set itemList {}
>         if {[string compare $dir ""] == 0} {
>             foreach volume [file volumes] {
>                 lappend itemList [list D[file nativename $volume] -1 D $volume]
>             }
>         } else {
>             foreach entry [glob -nocomplain -types {d f} -directory $dir *] {
>                 if {[catch {file mtime $entry} modTime] != 0} {
>                     continue
>                 }

>                 if {[file isdirectory $entry]} {
>                     lappend itemList [list D[file tail $entry] -1 \
>                         D[clock format $modTime -format "%Y-%m-%d %H:%M"] $entry]
>                 } else {
>                     lappend itemList [list F[file tail $entry] [file size $entry] \
>                         F[clock format $modTime -format "%Y-%m-%d %H:%M"] ""]
>                 }
>             }
>         }

>         #
>         # Sort the above list and insert it into the tablelist widget
>         # tbl as list of children of the row identified by nodeIdx
>         #
>         set itemList [$tbl applysorting $itemList]
>         $tbl insertchildlist $nodeIdx end $itemList

>         #
>         # Insert an image into the first cell of each newly inserted row
>         #
>         foreach item $itemList {
>             set name [lindex $item end]
>             if {[string compare $name ""] == 0} {                   ;# file
>                 $tbl cellconfigure $row,0 -image fileImg
>             } else {                                                ;# directory
>                 $tbl cellconfigure $row,0 -image clsdFolderImg
>                 $tbl rowattrib $row pathName $name

>                 #
>                 # Mark the row as collapsed if the directory is non-empty
>                 #
>                 if {[file readable $name] && [llength \
>                     [glob -nocomplain -types {d f} -directory $name *]] != 0} {
>                     $tbl collapse $row
>                 }
>             }

>             incr row
>         }

>         . . .
>     }

The main difference between the procedure `putContents` above and the procedure `demo::putChildren` described in the previous section is related to the way child items are inserted into the tablelist widget. Instead of inserting them individually with the aid of the `insertchild(ren)` tablelist subcommand, here we add the relevant data to a list of items and then invoke the much more performant `insertchildlist` subcommand. Also, instead of first inserting the items and then sorting them via `refreshsorting`, we first perform the necessary sortings on the above-mentioned list of items by invoking the `applysorting` subcommand. Again, this is much faster than sorting the already inserted child items.

This procedure also illustrates an effective technique based on the `-formatcommand` column configuration option: In the tablelist widget's internal list, the names and modification times of the directories and files are preceded by a `D` and `F`, respectively. This makes sure that the directories will sort before the files (when sorting in ascending order). When displaying the items, the Tablelist code will automatically invoke the `formatString` procedure, which removes the first character. Similarly, in the widget's internal list, the size of a directory is set to `-1`, which sorts before the sizes of the files. The `formatSize` procedure, invoked automatically when displaying the items, replaces this value with an empty string:

>     #------------------------------------------------------------------------------
>     # formatString
>     #
>     # Returns the substring obtained from the specified value by removing its first
>     # character.
>     #------------------------------------------------------------------------------
>     proc formatString val {
>         return [string range $val 1 end]
>     }

>     #------------------------------------------------------------------------------
>     # formatSize
>     #
>     # Returns an empty string if the specified value is negative and the value
>     # itself in user-friendly format otherwise.
>     #------------------------------------------------------------------------------
>     proc formatSize val {
>         if {$val < 0} {
>             return ""
>         } elseif {$val < 1024} {
>             return "$val bytes"
>         } elseif {$val < 1048576} {
>             return [format "%.1f KB" [expr {$val / 1024.0}]]
>         } elseif {$val < 1073741824} {
>             return [format "%.1f MB" [expr {$val / 1048576.0}]]
>         } else {
>             return [format "%.1f GB" [expr {$val / 1073741824.0}]]
>         }
>     }

Besides its common task of inserting the children of the row to be expanded, the `expandCmd` procedure shown below also changes the image contained in the first column to the one displaying an open folder. The `collapseCmd` procedure restores the image to the one displaying a closed folder:

>     #------------------------------------------------------------------------------
>     # expandCmd
>     #
>     # Outputs the content of the directory whose leaf name is displayed in the
>     # first cell of the specified row of the tablelist widget tbl, as child items
>     # of the one identified by row, and updates the image displayed in that cell.
>     #------------------------------------------------------------------------------
>     proc expandCmd {tbl row} {
>         if {[$tbl childcount $row] == 0} {
>             set dir [$tbl rowattrib $row pathName]
>             putContents $dir $tbl $row
>         }

>         if {[$tbl childcount $row] != 0} {
>             $tbl cellconfigure $row,0 -image openFolderImg
>         }
>     }

>     #------------------------------------------------------------------------------
>     # collapseCmd
>     #
>     # Updates the image displayed in the first cell of the specified row of the
>     # tablelist widget tbl.
>     #------------------------------------------------------------------------------
>     proc collapseCmd {tbl row} {
>         $tbl cellconfigure $row,0 -image clsdFolderImg
>     }

>     . . .

>     displayContents ""

The last line of the script invokes the procedure `displayContents` with an empty string as argument, i.e., displays the volumes mounted on the system.

### Improving the Look & Feel of a tablelist Widget

The script `styles.tcl` in the `demos` directory demonstrates some ways of making tablelist widgets smarter and improving the readability of their items. It creates 8 tablelist widgets, shown in the following figure:

Here is the relevant code segment:

>     #
>     # Create, configure, and populate 8 tablelist widgets
>     #
>     frame .f
>     for {set n 0} { $n < 8} {incr n} {
>         set tbl .f.tbl$n
>         tablelist::tablelist $tbl \
>             -columntitles {"Label 0" "Label 1" "Label 2" "Label 3"} \
>             -background white -height 4 -width 40 -stretch all
>         if {[$tbl cget -selectborderwidth] == 0} {
>             $tbl configure -spacing 1
>         }

>         switch $n {
>             1 {
>                 $tbl configure -showseparators yes
>             }
>             2 {
>                 $tbl configure -stripebackground #f0f0f0
>             }
>             3 {
>                 $tbl configure -stripebackground #f0f0f0 -showseparators yes
>             }
>             4 {
>                 $tbl columnconfigure 1 -background LightYellow
>                 $tbl columnconfigure 3 -background LightCyan
>             }
>             5 {
>                 $tbl configure -showseparators yes
>                 $tbl columnconfigure 1 -background LightYellow
>                 $tbl columnconfigure 3 -background LightCyan
>             }
>             6 {
>                 $tbl configure -stripebackground #f0f0f0
>                 $tbl columnconfigure 1 -background LightYellow \
>                     -stripebackground #f0f0d2
>                 $tbl columnconfigure 3 -background LightCyan \
>                     -stripebackground #d2f0f0
>             }
>             7 {
>                 $tbl configure -stripebackground #f0f0f0 -showseparators yes
>                 $tbl columnconfigure 1 -background LightYellow \
>                     -stripebackground #f0f0d2
>                 $tbl columnconfigure 3 -background LightCyan \
>                     -stripebackground #d2f0f0
>             }
>         }

>         foreach row {0 1 2 3} {
>             $tbl insert end \
>                  [list "Cell $row,0" "Cell $row,1" "Cell $row,2" "Cell $row,3"]
>         }
>     }

The only configuration option used here but not discussed in the first three examples (although already encountered in the previous one) is `-showseparators`. The visual effect it produces looks nice both by itself and combined with horizontal or vertical stripes, created by using the `-stripebackground` option and the `columnconfigure` subcommand, respectively.

### Advanced Interactive tablelist Cell Editing

The scripts `tileWidgets.tcl`, `bwidget.tcl`, `iwidgets.tcl`, and `miscWidgets.tcl` in the `demos` directory create a tablelist widget displaying some parameters of 16 serial lines, and demonstrate how to use various widgets from the Tk core and from the packages tile, BWidget, Iwidgets, combobox (by Bryan Oakley), ctext, and Mentry (or Mentry_tile) for interactive cell editing. The following figure shows the tablelist widget, together with a BWidget ComboBox used to edit the content of one of its cells:

Here is the relevant code segment from the script `bwidget.tcl` (the scripts `tileWidgets.tcl`, `iwidgets.tcl`, and `miscWidgets.tcl` are similar). A few parts of the code are shown in red color – we will return to this towards the end of the section.

>     package require Tk 8.4                          ;# because of "-compound"
>     package require tablelist 6.0
>     package require BWidget

>     wm title . "Serial Line Configuration"

>     #
>     # Add some entries to the Tk option database
>     #
>     set dir [file dirname [info script]]
>     source [file join $dir option.tcl]
>     option add *Tablelist*Entry.background white

>     #
>     # Register some widgets from the BWidget package for interactive cell editing
>     #
>     tablelist::addBWidgetEntry
>     tablelist::addBWidgetSpinBox
>     tablelist::addBWidgetComboBox

>     #
>     # Create the images "checkedImg" and "uncheckedImg", as well as 16 images of
>     # names like "img#FF0000", displaying colors identified by names like "red"
>     #
>     source [file join $dir images.tcl]

>     #
>     # Create a tablelist widget with editable columns (except the first one)
>     #
>     set tbl .tbl
>     tablelist::tablelist $tbl \
>         -columns {0 "No."             right
>                   0 "Available"       center
>                   0 "Name"            left
>                   0 "Baud Rate"       right
>                   0 "Data Bits"       center
>                   0 "Parity"          left
>                   0 "Stop Bits"       center
>                   0 "Handshake"       left
>                   0 "Activation Date" center
>                   0 "Activation Time" center
>                   0 "Cable Color"     center} \
>         -editstartcommand editStartCmd -editendcommand editEndCmd \
>         -height 0 -width 0
>     if {[$tbl cget -selectborderwidth] == 0} {
>         $tbl configure -spacing 1
>     }
>     $tbl columnconfigure 0 -sortmode integer
>     $tbl columnconfigure 1 -name available -editable yes -editwindow checkbutton \
>         -formatcommand emptyStr
>     $tbl columnconfigure 2 -name lineName  -editable yes -editwindow Entry \
>         -sortmode dictionary
>     $tbl columnconfigure 3 -name baudRate  -editable yes -editwindow ComboBox \
>         -sortmode integer
>     $tbl columnconfigure 4 -name dataBits  -editable yes -editwindow SpinBox
>     $tbl columnconfigure 5 -name parity    -editable yes -editwindow ComboBox
>     $tbl columnconfigure 6 -name stopBits  -editable yes -editwindow ComboBox
>     $tbl columnconfigure 7 -name handshake -editable yes -editwindow ComboBox
>     $tbl columnconfigure 8 -name actDate   -editable yes -editwindow Entry \
>         -formatcommand formatDate -sortmode integer
>     $tbl columnconfigure 9 -name actTime   -editable yes -editwindow Entry \
>         -formatcommand formatTime -sortmode integer
>     $tbl columnconfigure 10 -name color    -editable yes -editwindow menubutton \
>         -formatcommand emptyStr

>     proc emptyStr   val { return "" }
>     proc formatDate val { return [clock format $val -format "%Y-%m-%d"] }
>     proc formatTime val { return [clock format $val -format "%H:%M:%S"] }

>     #
>     # Populate the tablelist widget; set the activation
>     # date & time to 10 minutes past the current clock value
>     #
>     set clock [expr {[clock seconds] + 600}]
>     for {set i 0; set n 1} {$i < 16} {set i $n; incr n} {
>         $tbl insert end [list $n [expr {$i < 8}] "Line $n" 9600 8 None 1 XON/XOFF \
>             $clock $clock [lindex $colorNames $i]]

>         set availImg [expr {($i < 8) ? "checkedImg" : "uncheckedImg"}]
>         $tbl cellconfigure end,available -image $availImg
>         $tbl cellconfigure end,color -image img[lindex $colorValues $i]
>     }

>     set btn [button .btn -text "Close" -command exit]

>     #
>     # Manage the widgets
>     #
>     pack $btn -side bottom -pady 10
>     pack $tbl -side top -expand yes -fill both

We invoke the `tablelist::addBWidgetEntry`, `tablelist::addBWidgetSpinBox`, and `tablelist::addBWidgetComboBox` commands to register the Entry, SpinBox, and ComboBox widgets from the BWidget package for interactive cell editing. These commands return the values `"Entry"`, `"SpinBox"`, and `"ComboBox"`, respectively, which we then use in the `-editwindow` column configuration option to set the edit window for the columns no. 2, ..., 10. In columns no. 1 and 10 we use the Tk core checkbutton and menubutton widgets, which are automatically registered for interactive cell editing.

Notice the use of the `-name` column configuration option, which allows us to access the columns by their names instead of by numerical column indices. This is important, because the file `option.tcl`, which is `source`d into the main script, contains the line

>     option add *Tablelist.movableColumns    yes

The `editStartCmd` and `editEndCmd` procedures shown below use the `columncget` subcommand to retrieve the name of the column from the numerical column index.

By the way, two further option database settings contained in the file `option.tcl` are:

>     option add *Tablelist.labelCommand      tablelist::sortByColumn
>     option add *Tablelist.labelCommand2     tablelist::addToSortColumns

The `tablelist::sortByColumn` and `tablelist::addToSortColumns` commands specified in these settings enable the user to sort the items by one or more columns, with the aid of the left mouse button and of the `Shift` key.

The `editStartCmd` procedure, specified as the value of the `-editstartcommand` configuration option, needs the path name of the edit window, in order to be able to configure the widget in various ways. This is a common situation, and Tablelist provides the `editwinpath` subcommand for this purpose:

>     #------------------------------------------------------------------------------
>     # editStartCmd
>     #
>     # Applies some configuration options to the edit window; if the latter is a
>     # ComboBox, the procedure populates it.
>     #------------------------------------------------------------------------------
>     proc editStartCmd {tbl row col text} {
>         set w [$tbl editwinpath]

>         switch [$tbl columncget $col -name] {
>             lineName {
>                 #
>                 # Set an upper limit of 20 for the number of characters
>                 #
>                 $w configure -invalidcommand bell -validate key \
>                              -validatecommand {expr {[string length %P] <= 20}}
>             }

>             baudRate {
>                 #
>                 # Populate the ComboBox and allow no more
>                 # than 6 digits in its Entry component
>                 #
>                 $w configure -values {50 75 110 300 1200 2400 4800 9600 19200 38400
>                                       57600 115200 230400 460800 921600}
>                 $w configure -invalidcommand bell -validate key -validatecommand \
>                     {expr {[string length %P] <= 6 && [regexp {^[0-9]*$} %S]}}
>             }

>             dataBits {
>                 #
>                 # Configure the SpinBox
>                 #
>                 $w configure -range {5 8 1} -editable no
>             }

>             parity {
>                 #
>                 # Populate the ComboBox and make it non-editable
>                 #
>                 $w configure -values {None Even Odd Mark Space} -editable no
>             }

>             . . .

>             color {
>                 #
>                 # Populate the menu and make sure the menubutton will display the
>                 # color name rather than $text, which is "", due to -formatcommand
>                 #
>                 set menu [$w cget -menu]
>                 foreach name $::colorNames {
>                     $menu add radiobutton -compound left \
>                         -image img$::colors($name) -label $name
>                 }
>                 $menu entryconfigure 8 -columnbreak 1
>                 return [$tbl cellcget $row,$col -text]
>             }
>         }

>         return $text
>     }

The `editEndCmd` procedure, specified as the value of the `-editendcommand` configuration option, is responsible for a final validation of the edit window's text. Another purpose of this command is to convert the text contained in the edit window to the cell's new internal content, which is necessary because the internal value of the activation date and time is a clock value in seconds:

>     #------------------------------------------------------------------------------
>     # editEndCmd
>     #
>     # Performs a final validation of the text contained in the edit window and gets
>     # the cell's internal content.
>     #------------------------------------------------------------------------------
>     proc editEndCmd {tbl row col text} {
>         switch [$tbl columncget $col -name] {
>             available {
>                 #
>                 # Update the image contained in the cell
>                 #
>                 set img [expr {$text ? "checkedImg" : "uncheckedImg"}]
>                 $tbl cellconfigure $row,$col -image $img
>             }

>             baudRate {
>                 #
>                 # Check whether the baud rate is an integer in the range 50..921600
>                 #
>                 if {![regexp {^[0-9]+$} $text] || $text < 50 || $text > 921600} {
>                     bell
>                     tk_messageBox -title "Error" -icon error -message \
>                         "The baud rate must be an integer in the range 50..921600"
>                     $tbl rejectinput
>                 }
>             }

>             actDate {
>                 #
>                 # Get the activation date in seconds from the last argument
>                 #
>                 if {[catch {clock scan $text} actDate] != 0} {
>                     bell
>                     tk_messageBox -title "Error" -icon error -message "Invalid date"
>                     $tbl rejectinput
>                     return ""
>                 }

>                 #
>                 # Check whether the activation clock value is later than the
>                 # current one; if this is the case then make sure the cells
>                 # "actDate" and "actTime" will have the same internal value
>                 #
>                 set actTime [$tbl cellcget $row,actTime -text]
>                 set actClock [clock scan [formatTime $actTime] -base $actDate]
>                 if {$actClock <= [clock seconds]} {
>                     bell
>                     tk_messageBox -title "Error" -icon error -message \
>                         "The activation date & time must be in the future"
>                     $tbl rejectinput
>                 } else {
>                     $tbl cellconfigure $row,actTime -text $actClock
>                     return $actClock
>                 }
>             }

>             . . .

>             color {
>                 #
>                 # Update the image contained in the cell
>                 #
>                 $tbl cellconfigure $row,$col -image img$::colors($text)
>             }
>         }

>         return $text
>     }

Instead of making the `"Available"` column editable via a temporary checkbutton and displaying the images `"checkedImg"` and `"uncheckedImg"` in its cells, we can use the `embedcheckbuttons` subcommand to populate the column with persistently embedded checkbuttons. The necessary changes are as follows:

- Remove those parts of the code above that are shown in red color.
- Invoke

  >     $tbl embedcheckbuttons 1

  after populating the tablelist widget.

As mentioned above, the scripts `tileWidgets.tcl`, `iwidgets.tcl`, and `miscWidgets.tcl` are similar to `bwidget.tcl`. The first one makes use of the tile entry, spinbox, combobox, checkbutton, and menubutton widgets. The second one uses (besides the Tk core checkbutton and menubutton) the entryfield, spinint, combobox, dateentry, and timeentry widgets from the Iwidgets package and the validation facilities specific to that library. The third script makes use of the entry, spinbox, checkbutton, and menubutton widgets from the Tk core, Bryan Oakley's combobox, and of the mentry widgets of type `"Date"` and `"Time"`, and it performs the entry validation with the aid of the Wcb package (which is required anyway for the Mentry library).

### A tablelist Widget Containing Embedded Windows

The script `embeddedWindows.tcl` in the `demos` directory creates a tablelist widget whose items correspond to the Tk library scripts. The size of each file (in bytes) is not only displayed as a number, but is also illustrated with the aid of a frame with red background, created as a child of an embedded frame with ivory background. The files can be viewed by clicking on the corresponding embedded button widgets.

The following screenshot shows the tablelist widget with the mouse cursor over the first header label, causing this label to appear in `active` state:

First, we create and populate the tablelist widget:

>     package require tablelist 6.0

>     wm title . "Tk Library Scripts"

>     #
>     # Add some entries to the Tk option database
>     #
>     set dir [file dirname [info script]]
>     source [file join $dir option.tcl]

>     #
>     # Create the font TkFixedFont if not yet present
>     #
>     catch {font create TkFixedFont -family Courier -size -12}

>     #
>     # Create an image to be displayed in buttons embedded in a tablelist widget
>     #
>     image create photo openImg -file [file join $dir open.gif]

>     #
>     # Create a vertically scrolled tablelist widget with 5
>     # dynamic-width columns and interactive sort capability
>     #
>     set tf .tf
>     frame $tf -class ScrollArea
>     set tbl $tf.tbl
>     set vsb $tf.vsb
>     tablelist::tablelist $tbl \
>         -columns {0 "File Name" left
>                   0 "Bar Chart" center
>                   0 "File Size" right
>                   0 "View"      center
>                   0 "Seen"      center} \
>         -setgrid no -yscrollcommand [list $vsb set] -width 0
>     if {[$tbl cget -selectborderwidth] == 0} {
>         $tbl configure -spacing 1
>     }
>     $tbl columnconfigure 0 -name fileName
>     $tbl columnconfigure 1 -formatcommand emptyStr -sortmode integer
>     $tbl columnconfigure 2 -name fileSize -sortmode integer
>     $tbl columnconfigure 4 -name seen
>     scrollbar $vsb -orient vertical -command [list $tbl yview]

>     proc emptyStr val { return "" }

>     #
>     # Create a bold font
>     #
>     set tblFont [$tbl cget -font]
>     set size [font actual $tblFont -size]
>     if {$size == 0} {                                       ;# e.g., on Ubuntu
>         set size -12
>     }
>     eval font create BoldFont [font actual $tblFont] -size $size -weight bold

>     #
>     # Populate the tablelist widget
>     #
>     cd $tk_library
>     set totalSize 0
>     set maxSize 0
>     foreach fileName [lsort [glob *.tcl]] {
>         set fileSize [file size $fileName]
>         $tbl insert end [list $fileName $fileSize $fileSize "" no]

>         incr totalSize $fileSize
>         if {$fileSize > $maxSize} {
>             set maxSize $fileSize
>         }
>     }
>     $tbl header insert 0 [list "[$tbl size] *.tcl files" "" $totalSize "" ""]
>     $tbl header rowconfigure 0 -foreground blue

We insert the size of each file not only into the column with the title `"File Size"`, but also into the column `"Bar Chart"`. Since we configured this column with `-formatcommand emptyStr`, the text will remain hidden in it. It will, however, be needed when sorting the items by that column.

After populating the tablelist's body, we create a header item displaying the total number and size of the library files, by invoking the `header insert` subcommand, and change its foreground color with the aid of the `header rowconfigure` subcommand.

To be able to create the embedded windows, we have first to implement the creation scripts for them, as specified in the description of the `-window` cell configuration option. Here is the script that creates a frame to be embedded into the column displaying the bar chart:

>     #------------------------------------------------------------------------------
>     # createFrame
>     #
>     # Creates a frame widget w to be embedded into the specified cell of the
>     # tablelist widget tbl, as well as a child frame representing the size of the
>     # file whose name is diplayed in the first column of the cell's row.
>     #------------------------------------------------------------------------------
>     proc createFrame {tbl row col w} {
>         #
>         # Create the frame and replace the binding tag "Frame"
>         # with "TablelistBody" in the list of its binding tags
>         #
>         frame $w -width 102 -height 14 -background ivory -borderwidth 1 \
>                  -relief solid
>         bindtags $w [lreplace [bindtags $w] 1 1 TablelistBody]

>         #
>         # Create the child frame and replace the binding tag "Frame"
>         # with "TablelistBody" in the list of its binding tags
>         #
>         frame $w.f -height 12 -background red -borderwidth 1 -relief raised
>         bindtags $w.f [lreplace [bindtags $w] 1 1 TablelistBody]

>         #
>         # Manage the child frame
>         #
>         set fileSize [$tbl cellcget $row,fileSize -text]
>         place $w.f -relwidth [expr {double($fileSize) / $::maxSize}]
>     }

Since the frame will be embedded into the tablelist's body, we want to have the same handling of the mouse events in the frame and in its child frame as in the rest of the tablelist's body. To this end we replace the binding tag `Frame` (which has no own bindings anyway) with `TablelistBody`, thus making sure that the default binding scripts associated with that tag will be valid for the parent frame and its child, too.

We `place` the red child frame within its parent using the `-relwidth` option, to make sure that its width will remain proportional to the size of the corresponding file when resizing the parent frame (which will happen when resizing its column, as seen below).

The creation script for the buttons used for viewing the Tk library files is quite simple:

>     #------------------------------------------------------------------------------
>     # createButton
>     #
>     # Creates a button widget w to be embedded into the specified cell of the
>     # tablelist widget tbl.
>     #------------------------------------------------------------------------------
>     proc createButton {tbl row col w} {
>         set key [$tbl getkeys $row]
>         button $w -image openImg -highlightthickness 0 -takefocus 0 \
>                   -command [list viewFile $tbl $key]
>     }

>     #------------------------------------------------------------------------------
>     # viewFile
>     #
>     # Displays the content of the file whose name is contained in the row with the
>     # given key of the tablelist widget tbl.
>     #------------------------------------------------------------------------------
>     proc viewFile {tbl key} {
>         set top .top$key
>         if {[winfo exists $top]} {
>             raise $top
>             return ""
>         }

>         toplevel $top
>         set fileName [$tbl cellcget k$key,fileName -text]
>         wm title $top "File \"$fileName\""

>         #
>         # Create a vertically scrolled text widget as a grandchild of the toplevel
>         #
>         set tf $top.tf
>         frame $tf -class ScrollArea
>         set txt $tf.txt
>         set vsb $tf.vsb
>         text $txt -background white -font TkFixedFont -setgrid yes \
>                   -yscrollcommand [list $vsb set]
>         catch {$txt configure -tabstyle wordprocessor}      ;# for Tk 8.5 and above
>         scrollbar $vsb -orient vertical -command [list $txt yview]

>         #
>         # Insert the file's content into the text widget
>         #
>         set chan [open $fileName]
>         $txt insert end [read $chan]
>         close $chan

>         . . .

>         #
>         # Mark the file as seen
>         #
>         $tbl rowconfigure k$key -font BoldFont
>         $tbl cellconfigure k$key,seen -text yes
>     }

Each file will be displayed in a text widget contained in a top-level whose name is `.top$key`, where `$key` is obtained with the aid of the `getkeys` subcommand. By using the key instead of the row number, we will have a unique name for the top-level, even if the order of the items changes due to interactive sorting by a column. (Remember that the embedded windows will be destroyed and automatically recreated when sorting the items or moving the columns.)

Having implemented the creation scripts for the frames and buttons, we can now use the `cellconfigure` subcommand to effectively create these widgets as embedded windows. Notice the `-stretchwindow` option used for the embedded frames, to make sure that their width will be adapted to that of the containing column when the latter is being resized interactively.

>     #
>     # Create embedded windows in the columns no. 1 and 3
>     #
>     set rowCount [$tbl size]
>     for {set row 0} {$row < $rowCount} {incr row} {
>         $tbl cellconfigure $row,1 -window createFrame -stretchwindow yes
>         $tbl cellconfigure $row,3 -window createButton
>     }

### Tile-Based Demo Scripts

The Tablelist distribution contains also tile-based counterparts of the demo scripts discussed above. As described in the More on Tablelist_tile section of this tutorial, it is quite easy to port an application using the Tablelist package to one based on Tablelist_tile. For example, let's see how to transform the demo script `bwidget.tcl` into a tile-based one, called `bwidget_tile.tcl`. The changes are shown below in red color:

First, we replace the starting lines

>     package require Tk 8.3                          ;# because of entry validation
>     package require tablelist 6.0

with

>     package require tablelist_tile 6.0

and the command

>     source [file join $dir option.tcl]

with

>     source [file join $dir option_tile.tcl]

To ensure that the overall appearance of the GUI will conform to the currently used theme, we create a theme-specific container for our widgets:

>     #
>     # Improve the window's appearance by using a tile
>     # frame as a container for the other widgets
>     #
>     set f [ttk::frame .f]

This implies that we have to replace the statement

>     set tbl .tbl

defining the path name of our tablelist widget with

>     set tbl $f.tbl

Similarly, instead of a Tk button created by the command

>     set btn [button .btn -text "Close" -command exit]

we use a tile button that is a child of the above tile frame:

>     set btn [ttk::button $f.btn -text "Close" -command exit]

We manage this frame in the usual manner:

>     pack $f -expand yes -fill both

The script `option_tile.tcl` is nearly identical to `option.tcl`. Its tile-specific part uses the values written by the command `tablelist::setThemeDefaults` into the array `tablelist::themeDefaults`, to make sure that the selection will have the same theme-specific look in all the widgets created by the application:

>     tablelist::setThemeDefaults
>     if {[tablelist::getCurrentTheme] eq "aqua"} {
>         option add *Listbox.selectBackground \
>                    $tablelist::themeDefaults(-selectbackground)
>         option add *Listbox.selectForeground \
>                    $tablelist::themeDefaults(-selectforeground)
>     } else {
>         option add *selectBackground  $tablelist::themeDefaults(-selectbackground)
>         option add *selectForeground  $tablelist::themeDefaults(-selectforeground)
>     }
>     option add *selectBorderWidth     $tablelist::themeDefaults(-selectborderwidth)

The demo script `tileWidgets.tcl` uses not only the Tablelist_tile package for creating a tablelist widget with a modern theme-specific look & feel, but also the tile entry, spinbox, combobox, checkbutton, and menubutoon widgets for interactive cell editing. The resulting window has a nice theme-specific appearance:

The tile-based version of the demo script `embeddedWindows.tcl` contains a bit more changes, but most of them are not Tablelist-specific. Please take a look at the file `embeddedWindows_tile.tcl` in the `demos` directory for the details. Here is a screenshot of the resulting window:

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