path: root/Master/tlpkg/tlperl/lib/Tk/HList.pod

#  Copyright (c) 1996, Expert Interface Technologies
#  See the file "license.terms" for information on usage and redistribution
#  of this file, and for a DISCLAIMER OF ALL WARRANTIES.
#
#  The file man.macros and some of the macros used by this file are
#  copyrighted: (c) 1990 The Regents of the University of California.
#               (c) 1994-1995 Sun Microsystems, Inc.
#  The license terms of the Tcl/Tk distribution are in the file
#  license.tcl.

=head1 NAME

Tk::HList - Create and manipulate Tix Hierarchial List widgets

=for category  Tk Widget Classes

=head1 SYNOPSIS

I<$hlist> = I<$parent>-E<gt>B<HList>(?I<options>?);

=head1 STANDARD OPTIONS

B<-background>	B<-borderwidth>	B<-cursor>	B<-exportselection>
B<-foreground>	B<-font>	B<-height>	B<-highlightcolor>
B<-highlightthickness>	B<-relief>	B<-selectbackground>
B<-selectforeground>	B<-xscrollcommand>	B<-yscrollcommand>
B<-width>

See L<Tk::options> for details of the standard options.

=head1 WIDGET-SPECIFIC OPTIONS

=over 4

=item Name:	B<browsecmd>

=item Class:	B<BrowseCmd>

=item Switch:	B<-browsecmd>

Specifies a perl/Tk L<callback|Tk::callbacks> to be executed when the user browses through the
entries in the HList widget.

=item Name:	B<columns>

=item Class:	B<Columns>

=item Switch:	B<-columns>

Specifies the number of columns in this HList widget. This option can
only be set during the creation of the HList widget and cannot be
changed subsequently.

=item Name:	B<command>

=item Class:	B<Command>

=item Switch:	B<-command>

Specifies the perl/Tk L<callback|Tk::callbacks> to be executed when the user invokes a list
entry in the HList widget. Normally the user invokes a list
entry by double-clicking it or pressing the Return key.

=item Name:	B<drawBranch>

=item Class:	B<DrawBranch>

=item Switch:	B<-drawbranch>

A Boolean value to specify whether branch line should be drawn to
connect list entries to their parents.

=item Name:	B<foreground>

=item Class:	B<Foreground>

=item Switch:	B<-foreground>

=item Alias:	B<-fg>

B<[OBSOLETE]> Specifies the default foreground color for the list entries.

=item Name:	B<gap>

=item Class:	B<Gap>

=item Switch:	B<-gap>

B<[OBSOLETE]> The default distance between the bitmap/image and the
text in list entries.

=item Name:	B<header>

=item Class:	B<Header>

=item Switch:	B<-header>

A Boolean value specifying whether headers should be displayed for
this HList widget (see the B<header> method below).

=item Name:	B<height>

=item Class:	B<Height>

=item Switch:	B<-height>

Specifies the desired height for the window in number of characters.

=item Name:	B<indent>

=item Class:	B<Indent>

=item Switch:	B<-indent>

Specifies the amount of horizontal indentation between a list entry
and its children. Must be a valid screen distance value.

=item Name:	B<indicator>

=item Class:	B<Indicator>

=item Switch:	B<-indicator>

Specifies whether the indicators should be displayed inside the HList
widget. See the B<indicator> method below.

=item Name:	B<indicatorCmd>

=item Class:	B<IndicatorCmd>

=item Switch:	B<-indicatorcmd>

Specifies a perl/Tk L<callback|Tk::callbacks> to be executed when the user manipulates the
indicator of an HList entry. The B<-indicatorcmd> is triggered
when the user press or releases the mouse button over the indicator in
an HList entry. By default the perl/Tk B<callback> specified by
B<-indicatorcmd> is executed with two additional arguments, the
entryPath of the entry whose indicator has been triggered and additional
information about the event.  The additional information is one of the
following strings:  B<E<lt>ArmE<gt>>, B<E<lt>DisarmE<gt>>,
and B<E<lt>ActivateE<gt>>.

=item Name:	B<itemType>

=item Class:	B<ItemType>

=item Switch:	B<-itemtype>

Specifies the default type of display item for this HList widget. When
you call the B<itemCreate>, B<add> and B<addchild> methods, display
items of this
type will be created if the B<-itemtype> option is not specified .

=item Name:	B<padX>

=item Class:	B<Pad>

=item Switch:	B<-padx>

B<[OBSOLETE]> The default horizontal padding for list entries.

=item Name:	B<padY>

=item Class:	B<Pad>

=item Switch:	B<-padx>

B<[OBSOLETE]> The default vertical padding for list entries.

=item Name:	B<selectBackground>

=item Class:	B<SelectBackground>

=item Switch:	B<-selectbackground>

Specifies the background color for the selected list entries.

=item Name:	B<selectBorderWidth>

=item Class:	B<BorderWidth>

=item Switch:	B<-selectborderwidth>

Specifies a non-negative value indicating the width of the 3-D border
to draw around selected items.  The value may have any of the forms
acceptable to B<Tk_GetPixels>.

=item Name:	B<selectForeground>

=item Class:	B<SelectForeground>

=item Switch:	B<-selectforeground>

Specifies the foreground color for the selected list entries.

=item Name:	B<selectMode>

=item Class:	B<SelectMode>

=item Switch:	B<-selectmode>

Specifies one of several styles for manipulating the selection.  The
value of the option may be arbitrary, but the default bindings expect
it to be either B<single>, B<browse>, B<multiple>, or
B<extended>; the default value is B<single>.

=item Name:	B<sizeCmd>

=item Class:	B<SizeCmd>

=item Switch:	B<-sizecmd>

Specifies a perl/Tk L<callback|Tk::callbacks> to be called whenever the HList widget
changes its size.  This method can be useful to implement ``I<user scroll
bars when needed>'' features.

=item Name:	B<separator>

=item Class:	B<Separator>

=item Switch:	B<-separator>

Specifies the character to used as the separator character when
intepreting the path-names of list entries. By default the character
"." is used.

=item Name:	B<width>

=item Class:	B<Width>

=item Switch:	B<-width>

Specifies the desired width for the window in characters.

=back

=head1 DESCRIPTION

The B<HList> method creates a new window (given by the
$widget argument) and makes it into a HList widget.
Additional options, described above, may be specified on the command
line or in the option database to configure aspects of the
HList widget such as its cursor and relief.

The HList widget can be used to display any data that have a
hierarchical structure, for example, file system directory trees. The
list entries are indented and connected by branch lines according to
their places in the hierachy.

Each list entry is identified by an B<entryPath>. The entryPath is a
sequence of B<entry names> separated by the separator charactor
(specified by the B<-separator> option). An B<entry name> can be
any string that does not contain the separator charactor, or it can be
the a string that contains only one separator charactor.

For example, when "." is used as the separator charactor,
"one.two.three" is the entryPath for a list entry whose parent is
"one.two", whose parent is "one", which is a toplevel entry (has no
parents).

Another examples: ".two.three" is the entryPath for a list entry whose
parent is ".two", whose parent is ".", which is a toplevel entry.

=head1 DISPLAY ITEMS

Each list entry in an HList widget is associated with a B<display>
item.  The display item determines what visual information should
be displayed for this list entry. Please see L<Tk::DItem>
for a list of all display items.
When a list entry is created by the B<itemCreate>, B<add> or
B<addchild> widget
methods, the type of its display item is determined by the
B<-itemtype> option passed to these methods. If the
B<-itemtype> is omitted, then by default the type specified by
this HList widget's B<-itemtype> option is used.

=head1 WIDGET METHODS

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

The following additional methods are available HList widgets:

=over 4

=item I<$hlist>-E<gt>B<add>(I<$entryPath> ?,I<option>=E<gt>I<value>, ...?)

Creates a new list entry with the pathname I<$entryPath>. A list
entry must be created after its parent is created (unless this entry
is a top-level entry, which has no parent).  See also L<"BUGS"> below.
This method returns the
entryPath of the newly created list entry. The following
configuration options can be given to configure the list entry:

=over 8

=item B<-at> =E<gt> I<position>

Insert the new list at the position given by I<position>.
I<position> must be a valid integer. The position B<0> indicates
the first position, B<1> indicates the second position, and so on.

=item B<-after> =E<gt> I<afterWhich>

Insert the new list entry after the entry identified by
I<afterWhich>. I<afterWhich> must be a valid list entry and it
mush have the same parent as the new list entry

=item B<-before> =E<gt> I<beforeWhich>

Insert the new list entry before the entry identified by
I<beforeWhich>. I<beforeWhich> must be a valid list entry and it
mush have the same parent as the new list entry

=item B<-data> =E<gt> I<string>

Specifies a string to associate with this list entry. This string can
be queried by the B<info> method. The application
programmer can use the B<-data> option to associate the list entry
with the data it represents.

=item B<-itemtype> =E<gt> I<type>

Specifies the type of display item to be display for the new list
entry. B<type> must be a valid display item type. Currently the
available display item types are B<imagetext>, B<text>, and
$widget. If this option is not specified, then by default the
type specified by this HList widget's B<-itemtype> option is used.

=item B<-state> =E<gt> I<state>

Specifies whether this entry can be selected or invoked by the user.
Must be either B<normal> or B<disabled>.

=back

The B<add> method accepts additional configuration options
to configure the display item associated with this list entry. The set
of additional configuration options depends on the type of the display
item given by the B<-itemtype> option. Please see
L<Tk::DItem> for a list of the configuration options for
each of the display item types.

=item I<$hlist>-E<gt>B<addchild>(I<$parentPath, >?I<option, value, ..., >?)

Adds a new child entry to the children list of the list entry
identified by I<$parentPath>. Or, if I<$parentPath> is set to be
the empty string, then creates a new toplevel entry. The name of the
new list entry will be a unique name automatically generated by the
HList widget. Usually if I<$parentPath> is B<foo>, then the
entryPath of the new entry will be B<foo.0>, B<foo.1>, ... etc.
This method returns the entryPath of the newly created list entry.
I<option> can be any option for the B<add> method.
See also L<"BUGS"> below.

=item I<$hlist>-E<gt>B<anchorSet>(I<$entryPath>)

Sets the anchor to the list entry identified by I<$entryPath>.  The
anchor is the end of the selection that is fixed while the user is
dragging out a selection with the mouse.

=item I<$hlist>-E<gt>B<anchorClear>

Removes the anchor, if any, from this HList widget. This only
removes the surrounding highlights of the anchor entry and does not
affect its selection status.

=item I<$hlist>-E<gt>B<columnWidth>(I<$col>?, I<-char>?, ?I<width>?)

Querys or sets the width of a the column I<$col> in the HList
widget. The value of I<$col> is zero-based: 0 stands for the first
column, 1 stands for the second, and so on. If no further parameters
are given, returns the current width of this column (in number of
pixels). Additional parameters can be given to set the width of this
column:

=over 8

=item I<$hlist>-E<gt>B<columnWidth>(I<$col>, B<''>)

An empty string indicates that the width of the column should be just
wide enough to display the widest element in this column. In this
case, the width of this column may change as a result of the elements
in this column changing their sizes.

=item I<$hlist>-E<gt>B<columnWidth>(I<$col, >I<width>)

I<width> must be in a form accepted by B<Tk_GetPixels>.

=item I<$hlist>-E<gt>B<columnWidth>(I<$col, >B<-char, >I<nChars>)

The width is set to be the average width occupied by I<nChars>
number of characters of the font specified by the B<-font> option
of this HList widget.

=back

=item I<$hlist>-E<gt>B<delete>(I<option>, I<$entryPath>)

Delete one or more list entries. I<option> may be one of the
following:

=over 8

=item B<all>

Delete all entries in the HList. In this case the I<$entryPath>
does not need to be specified.

=item B<entry>

Delete the entry specified by I<$entryPath> and all its offsprings,
if any.

=item B<offsprings>

Delete all the offsprings, if any, of the entry specified by
I<$entryPath>. However, I<$entryPath> itself is not deleted.

=item B<siblings>

Delete all the list entries that share the same parent with the entry
specified by I<$entryPath>. However, I<$entryPath> itself is not
deleted.

=back

=item I<$hlist>-E<gt>B<dragsiteSet>(I<$entryPath>)

Sets the dragsite to the list entry identified by
I<$entryPath>. The dragsite is used to indicate the source of a
drag-and-drop action. Currently drag-and-drop functionality has not
been implemented in Tix yet.

=item I<$hlist>-E<gt>B<dragsiteClear>

Remove the dragsite, if any, from the this HList widget. This only
removes the surrounding highlights of the dragsite entry and does not
affect its selection status.

=item I<$hlist>-E<gt>B<dropsiteSet>(I<$entryPath>)

Sets the dropsite to the list entry identified by I<$entryPath>. The
dropsite is used to indicate the target of a drag-and-drop
action. Currently drag-and-drop functionality has not been implemented
in Tix yet.

=item I<$hlist>-E<gt>B<dropsiteClear>

Remove the dropsite, if any, from the this HList widget. This only
removes the surrounding highlights of the dropsite entry and does not
affect its selection status.

=item I<$hlist>-E<gt>B<entrycget>(I<$entryPath>, I<option>)

Returns the current value of the configuration option given by
I<option> for the entry indentfied by I<$entryPath>. I<Option>
may have any of the values accepted by the B<add> method.

=item I<$hlist>-E<gt>B<entryconfigure>(I<$entryPath> ?,I<option>?, ?I<value>=E<gt>I<option>, ...?)

Query or modify the configuration options of the list entry indentfied
by I<$entryPath>. If no I<option> is specified, returns a list
describing all of the available options for I<$entryPath> (see
L<Tk::options> for information on the format of this list.) If
I<option> is specified with no I<value>, then the method
returns a list describing the one named option (this list will be
identical to the corresponding sublist of the value returned if no
I<option> is specified). If one or more I<option-value> pairs
are specified, then the method modifies the given option(s) to have
the given value(s); in this case the method returns an empty string.
I<Option> may have any of the values accepted by the B<add> or
B<addchild> method. The exact set of options depends on the
value of the B<-itemtype> option passed to the the B<add> or
B<addchild> method when this list entry is created.

=item I<$hlist>-E<gt>B<header>(I<option>, I<$col> ?,I<args>, ...?)

Manipulates the header items of this HList widget. If the
B<-header> option of this HList widget is set to true, then a
header item is displayed at the top of each column. The I<$col>
argument for this method must be a valid integer. 0 indicates the
first column, 1 the second column, ... and so on. This method
supports the following options:

=over 8

=item I<$hlist>-E<gt>B<header>(B<cget>, I<$col>, I<option>)

If the I<$col>-th column has a header display item, returns the
value of the specified I<option> of the header item. If the header
doesn't exist, returns an error.

=item I<$hlist>-E<gt>B<header>(B<configure, >I<$col, >?I<option>?, I<?value, option, value, ...>?)

Query or modify the configuration options of the header display item
of the I<$col>-th column. The header item must exist, or an error
will result.  If no I<option> is specified, returns a list
describing all of the available options for the header display item
(see L<Tk::options> for information on the format of this
list.) If I<option> is specified with no I<value>, then the
method returns a list describing the one named option (this list will
be identical to the corresponding sublist of the value returned if no
I<option> is specified). If one or more I<option-value> pairs
are specified, then the method modifies the given option(s) to have
the given value(s); in this case the method returns an empty
string. I<Option> may have any of the values accepted by the
B<header create> method. The exact set of options depends
on the value of the B<-itemtype> option passed to the the B<header>
create method when this display item was created.

=item I<$hlist>-E<gt>B<header>(B<create, >I<$col, >?I<-itemtype type>? ?I<option value ...>?

Creates a new display item as the header for the I<$col>-th
column. See also L<"BUGS"> below.
If an header display item already exists for this column, it
will be replaced by the new item.  An optional parameter
I<-itemtype> can be used to specify what type of display item
should be created. If the I<-itemtype> is not given, then by
default the type specified by this HList widget's B<-itemtype>
option is used. Additional parameters, in I<option-value> pairs,
can be passed to configure the appearance of the display item. Each
I<option-value> pair must be a valid option for this type of
display item or one of the following:

=over 12

=item B<-borderwidth> =E<gt> I<color>

Specifies the border width of this header item.

=item B<-headerbackground> =E<gt> I<color>

Specifies the background color of this header item.

=item B<-relief> =E<gt> I<type>

Specifies the relief type of the border of this header item.

=back

=item I<$hlist>-E<gt>B<header>(B<delete, >I<$col>)

Deletes the header display item for the I<$col>-th column.

=item I<$hlist>-E<gt>B<header>(B<exists, >I<$col>)

Return true if an header display item exists for the I<$col>-th
column; return false otherwise.

=item I<$hlist>-E<gt>B<header>(B<size>, I<$col>)

If an header display item exists for the I<$col>-th column , returns
its size in pixels in a two element list I<(width, height)>;
returns an error if the header display item does not exist.

=back

=item I<$hlist>-E<gt>B<hide>(I<option> ?,I<$entryPath>?)

Makes some of entries invisible without deleting them.
I<Option> can be one of the following:

=over 8

=item B<entry>

Hides the list entry identified by I<$entryPath>.

=back

Currently only the B<entry> option is supported. Other options will
be added in the next release.

=item I<$hlist>-E<gt>B<indicator>(I<option>, I<$entryPath>, ?I<args, ...>?)

Manipulates the indicator on the list entries. An indicator is usually
a small display item (such as an image) that is displayed to the left
to an entry to indicate the status of the entry.  For example, it may
be used to indicate whether a directory is opened or
closed.  I<Option> can be one of the following:

=over 8

=item I<$hlist>-E<gt>B<indicator>(B<cget>, I<$entryPath>, I<option>)

If the list entry given by I<$entryPath> has an indicator, returns
the value of the specified I<option> of the indicator. If the
indicator doesn't exist, returns an error.

=item I<$hlist>-E<gt>B<indicator>(B<configure>, I<$entryPath>, ?I<option>?, I<?value, option, value, ...>?)

Query or modify the configuration options of the indicator display
item of the entry specified by I<$entryPath>. The indicator item
must exist, or an error will result.  If no I<option> is specified,
returns a list describing all of the available options for the
indicator display item (see L<Tk::options> for information
on the format of this list). If I<option> is specified with no
I<value>, then the method returns a list describing the one named
option (this list will be identical to the corresponding sublist of
the value returned if no I<option> is specified). If one or more
I<option-value> pairs are specified, then the method modifies the
given option(s) to have the given value(s); in this case the method
returns an empty string.  I<Option> may have any of the values
accepted by the B<indicator create> method. The exact set
of options depends on the value of the B<-itemtype> option passed
to the the B<indicator create> method when this display item
was created.

=item I<$hlist>-E<gt>B<indicator>(B<create, >I<$entryPath, >?, I<-itemtype type>? ?I<option value ...>?)

Creates a new display item as the indicator for the entry specified by
I<$entryPath>. If an indicator display item already exists for this
entry, it will be replaced by the new item.  An optional parameter
I<-itemtype> can be used to specify what type of display item
should be created. If the I<-itemtype> is not given, then by
default the type specified by this HList widget's B<-itemtype>
option is used. Additional parameters, in I<option-value> pairs,
can be passed to configure the appearance of the display item. Each
I<option-value> pair must be a valid option for this type of
display item.

=item I<$hlist>-E<gt>B<indicator>(B<delete>, I<$entryPath>)

Deletes the indicator display item for the entry given by I<$entryPath>.

=item I<$hlist>-E<gt>B<indicator>(B<exists>, I<$entryPath>)

Return true if an indicator display item exists for the entry given by
I<$entryPath>; return false otherwise.

=item I<$hlist>-E<gt>B<indicator>(B<size>, I<$entryPath>)

If an indicator display item exists for the entry given by
I<$entryPath>, returns its size in a two element list of the form
{I<width height>}; returns an error if the indicator display item
does not exist.

=back

=item I<$hlist>-E<gt>B<info>(I<option>, I<arg, ...>)

Query information about the HList widget. I<option> can be one
of the following:

=over 8

=item I<$hlist>-E<gt>B<info>(B<anchor>)

Returns the entryPath of the current anchor, if any, of the HList
widget. If the anchor is not set, returns the empty string.

=item I<$hlist>-E<gt>B<infoBbox>(I<$entryPath>)

Returns a list of four numbers describing the visible bounding box of
the entry given I<$entryPath>. The first two elements of the list
give the x and y coordinates of the upper-left corner of the screen
area covered by the entry (specified in pixels relative to the widget)
and the last two elements give the lower-right corner of the area, in
pixels. If no part of the entry given by index is visible on the
screen then the result is an empty string; if the entry is partially
visible, the result gives the only the visible area of the entry.

=item I<$hlist>-E<gt>B<info>(B<children> ?,I<$entryPath>?)

If I<$entryPath> is given, returns a list of the entryPath's of its
children entries. Otherwise returns a list of the toplevel
entryPath's.

=item I<$hlist>-E<gt>B<info>(B<data> ?,I<$entryPath>?)

Returns the data associated with I<$entryPath>.

=item I<$hlist>-E<gt>B<info>(B<dragsite>)

Returns the entryPath of the current dragsite, if any, of the HList
widget. If the dragsite is not set, returns the empty string.

=item I<$hlist>-E<gt>B<info>(B<dropsite>)

Returns the entryPath of the current dropsite, if any, of the HList
widget. If the dropsite is not set, returns the empty string.

=item I<$hlist>-E<gt>B<info>(B<exists>, I<$entryPath>)

Returns a boolean value indicating whether the list entry
I<$entryPath> exists.

=item I<$hlist>-E<gt>B<info>(B<hidden>, I<$entryPath>)

Returns a boolean value indicating whether the list entry
B<$entryPath> is hidden or not.

=item I<$hlist>-E<gt>B<info>(B<next>, I<$entryPath>)

Returns the entryPath of the list entry, if any, immediately below
this list entry. If this entry is already at the bottom of the HList
widget, returns an empty string.

=item I<$hlist>-E<gt>B<info>(B<parent>, I<$entryPath>)

Returns the name of the parent of the list entry identified by
I<$entryPath>. If I<entryPath> is a toplevel list entry,
returns the empty string.

=item I<$hlist>-E<gt>B<info>(B<prev>, I<$entryPath>)

Returns the entryPath of the list entry, if any, immediately above
this list entry. If this entry is already at the top of the HList
widget, returns an empty string.

=item I<$hlist>-E<gt>B<info>(B<selection>)

Returns a list of selected entries in the HList widget. In scalar
context, returns an anonymous list of the selected entries.
If no entries are selected, undef is returned in scalar context, and
an empty list otherwise.

=back

=item I<$hlist>-E<gt>B<item>(I<option, >?I<args, ...>?)

Creates and configures the display items at individual columns the
entries. The form of additional of arguments depends on the choice of
I<option>:

=over 8

=item I<$hlist>-E<gt>B<itemCget>(I<$entryPath>, I<$col>, I<option>)

Returns the current value of the configure I<option> of the display
item at the column designated by I<$col> of the entry specified by
I<$entryPath>.

=item I<$hlist>-E<gt>B<itemConfigure>(I<$entryPath>, I<$col> ?,I<option>?, I<?value, option, value, ...>?)

Query or modify the configuration options of the display item at the
column designated by I<$col> of the entry specified by
I<$entryPath>. If no I<option> is specified, returns a list
describing all of the available options for I<$entryPath> (see
L<Tk::options> for information on the format of this
list). If I<option> is specified with no I<value>, then the
method returns a list describing the one named option (this list will
be identical to the corresponding sublist of the value returned if no
I<option> is specified). If one or more I<option-value> pairs
are specified, then the method modifies the given option(s) to have
the given value(s); in this case the method returns an empty string.
I<Option> may have any of the values accepted by the B<item>
create method. The exact set of options depends on the
value of the B<-itemtype> option passed to the the B<item>
create method when this display item was created.

=item I<$hlist>-E<gt>B<itemCreate>(I<$entryPath>, I<$col> ?,I<-itemtype>=E<gt>I<type>? ?,I<option value ...>?)

Creates a new display item at the column designated by I<$col> of
the entry specified by I<$entryPath>. An optional parameter
I<-itemtype> can be used to specify what type of display items
should be created. If the I<-itemtype> is not specified, then by
default the type specified by this HList widget's B<-itemtype>
option is used.  Additional parameters, in I<option-value> pairs,
can be passed to configure the appearance of the display item. Each
I<option- value> pair must be a valid option for this type of
display item.

=item I<$hlist>-E<gt>B<itemDelete>(I<$entryPath>, I<$col>)

Deletes the display item at the column designated by I<$col> of
the entry specified by I<$entryPath>.

=item I<$hlist>-E<gt>B<itemExists>(I<$entryPath>, I<$col>)

Returns true if there is a display item at the column designated by
I<$col> of the entry specified by I<$entryPath>; returns false
otherwise.

=back

=item I<$hlist>-E<gt>B<nearest>(I<y>)

I<$hlist>-E<gt>B<nearest>(I<y>)
Given a y-coordinate within the HList window, this method returns
the entryPath of the (visible) HList element nearest to that
y-coordinate.

=item I<$hlist>-E<gt>B<see>(I<$entryPath>)

Adjust the view in the HList so that the entry given by I<$entryPath> is
visible. If the entry is already visible then the method has no
effect; if the entry is near one edge of the window then the HList
scrolls to bring the element into view at the edge; otherwise the
HList widget scrolls to center the entry.

=item I<$hlist>-E<gt>B<selection>(I<option>, I<arg>, ...)

=item I<$hlist>-E<gt>B<selection>I<Option>(I<arg>, ...)

This method is used to adjust the selection within a HList widget. It
has several forms, depending on I<option>:

=over 8

=item I<$hlist>-E<gt>B<selectionClear>(?I<from>?, ?I<to>?)

When no extra arguments are given, deselects all of the list entrie(s)
in this HList widget. When only I<from> is given, only the list
entry identified by I<from> is deselected. When both I<from> and
I<to> are given, deselects all of the list entrie(s) between
between I<from> and I<to>, inclusive, without affecting the
selection state of elements outside that range.

=item I<$hlist>-E<gt>B<selectionGet>

This is an alias for the B<infoSelection> method.

=item I<$hlist>-E<gt>B<selectionIncludes>(I<$entryPath>)

Returns 1 if the list entry indicated by I<$entryPath> is currently
selected; returns 0 otherwise.

=item I<$hlist>-E<gt>B<selectionSet>(I<from>?, I<to>?)

Selects all of the list entrie(s) between between I<from> and
I<to>, inclusive, without affecting the selection state of entries
outside that range. When only I<from> is given, only the list entry
identified by I<from> is selected.

=back

=item I<$hlist>-E<gt>B<show>(I<option> ?,I<$entryPath>?)

Show the entries that are hidden by the B<hide> method,
I<option> can be one of the following:

=over 8

=item B<entry>

Shows the list entry identified by I<$entryPath>.

=back

Currently only the B<entry> option is supported. Other options will
be added in future releases.

=item I<$hlist>-E<gt>B<xview>(I<args>)

This method is used to query and change the horizontal position of the
information in the widget's window. It can take any of the following
forms:

=over 8

=item I<$hlist>-E<gt>B<xview>

Returns a list containing two elements.  Each element is a real
fraction between 0 and 1; together they describe the horizontal span
that is visible in the window.  For example, if the first element is
.2 and the second element is .6, 20% of the HList entry is
off-screen to the left, the middle 40% is visible in the window, and
40% of the entry is off-screen to the right. These are the same values
passed to scrollbars via the B<-xscrollcommand> option.

=item I<$hlist>-E<gt>B<xview>(I<$entryPath>)

Adjusts the view in the window so that the list entry identified by
I<$entryPath> is aligned to the left edge of the window.

=item I<$hlist>-E<gt>B<xview>(B<moveto> =E<gt> I<fraction>)

Adjusts the view in the window so that I<fraction> of the total
width of the HList is off-screen to the left. I<fraction> must be
a fraction between 0 and 1.

=item I<$hlist>-E<gt>B<xview>(B<scroll> =E<gt> I<number, what>)

This method shifts the view in the window left or right according to
I<number> and I<what>. I<Number> must be an integer.
I<What> must be either B<units> or B<pages> or an
abbreviation of one of these. If I<what> is B<units>, the view
adjusts left or right by I<number> character units (the width of
the B<0> character) on the display; if it is B<pages> then the
view adjusts by I<number> screenfuls. If I<number> is negative
then characters farther to the left become visible; if it is positive
then characters farther to the right become visible.

=back

=item I<$hlist>-E<gt>B<yview>(I<?args>?)

This method is used to query and change the vertical position of the
entries in the widget's window. It can take any of the following forms:

=over 8

=item I<$hlist>-E<gt>B<yview>

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

=item I<$hlist>-E<gt>B<yview>(I<$entryPath>)

Adjusts the view in the window so that the list entry given by
I<$entryPath> is displayed at the top of the window.

=item I<$hlist>-E<gt>B<yview>(B<moveto> =E<gt> I<fraction>)

Adjusts the view in the window so that the list entry given by
I<fraction> appears at the top of the window. I<Fraction> is a
fraction between 0 and 1; 0 indicates the first entry in the
HList, 0.33 indicates the entry one-third the way through the
HList, and so on.

=item I<$hlist>-E<gt>B<yview>(B<scroll> =E<gt> I<number, what>)

This method adjust the view in the window up or down according to
I<number> and I<what>.  I<Number> must be an integer.
I<What> must be either B<units> or B<pages>.  If I<what>
is B<units>, the view adjusts up or down by I<number> lines; if
it is B<pages> then the view adjusts by I<number> screenfuls.
If I<number> is negative then earlier entries become visible; if
it is positive then later entries become visible.

=back

=back

=head1 BINDINGS

=over 4

=item [1]

If the B<-selectmode> is "browse", when the user drags the mouse
pointer over the list entries, the entry under the pointer will be
highlighted and the B<-browsecmd> callback will be called with
one parameter, the entryPath of the highlighted entry. Only one entry
can be highlighted at a time. The B<-command> callback will be
called when the user double-clicks on a list entry.

=item [2]

If the B<-selectmode> is "single", the entries will only be
highlighted by mouse E<lt>ButtonRelease-1E<gt> events. When a new list entry
is highlighted, the B<-browsecmd> callback will be called with
one parameter indicating the highlighted list entry. The
B<-command> callback will be called when the user double-clicks
on a list entry.

=item [3]

If the B<-selectmode> is "multiple", when the user drags the mouse
pointer over the list entries, all the entries under the pointer will
be highlighted. However, only a contiguous region of list entries can
be selected. When the highlighted area is changed, the
B<-browsecmd> callback will be called with an undefined
parameter. It is the responsibility of the B<-browsecmd> callback
to find out the exact highlighted selection in the HList. The
B<-command> callback will be called when the user double-clicks
on a list entry.

=item [4]

If the B<-selectmode> is "extended", when the user drags the mouse
pointer over the list entries, all the entries under the pointer will
be highlighted. The user can also make disjointed selections using
E<lt>Control-ButtonPress-1E<gt>. When the highlighted area is changed, the
B<-browsecmd> callback will be called with an undefined
parameter. It is the responsibility of the B<-browsecmd> callback
to find out the exact highlighted selection in the HList. The
B<-command> callback will be called when the user double-clicks
on a list entry.

=item [5]

B<Arrow key bindings:> E<lt>UpE<gt> arrow key moves the anchor point to the
item right on top of the current anchor item. E<lt>DownE<gt> arrow key moves
the anchor point to the item right below the current anchor item.
E<lt>LeftE<gt> arrow key moves the anchor to the parent item of the current
anchor item. E<lt>RightE<gt> moves the anchor to the first child of the
current anchor item. If the current anchor item does not have any
children, moves the anchor to the item right below the current anchor
item.

=back

=head1 EXAMPLE

This example demonstrates how to use an HList to store a file
directory structure and respond to the user's browse events:

   use strict;
   use Tk;
   use Tk::Label;
   use Tk::HList;

   my $mw = MainWindow->new();
   my $label = $mw->Label(-width=>15);
   my $hlist = $mw->HList(
                       -itemtype   => 'text',
                       -separator  => '/',
                       -selectmode => 'single',
                       -browsecmd  => sub {
                                 my $file = shift;
                                 $label->configure(-text=>$file);
                              }
                       );

   foreach ( qw(/ /home /home/ioi /home/foo /usr /usr/lib) ) {
       $hlist->add($_, -text=>$_);
   }

   $hlist->pack;
   $label->pack;

   MainLoop;

=head1 BUGS

The fact that the display item at column 0 is implicitly associated
with the whole entry is probably a design bug. This was done for
backward compatibility purposes. The result is that there is a large
overlap between the B<item> method and the B<add>,
B<addchild>, B<entrycget> and B<entryconfigure>
methods.  Whenever multiple columns exist, the programmer should use
ONLY the B<item> method to create and configure the display items
in each column; the B<add>, B<addchild>, B<entrycget> and
B<entryconfigure> should be used ONLY to create and configure
entries.

=head1 KEYWORDS

Hierarchical Listbox

=head1 SEE ALSO

L<Tk::DItem|Tk::DItem>

=cut