This method uses Tk::Dialog to quickly create several
common dialog boxes. A dialog widget consists of a message, an icon
and a set of buttons (see the -type option). After the message
window is popped up, messageBox waits for the user to select one of
the buttons and return the button text (note that it's best to check the
returned value in a case insensitive manner). NOTE: unlike
Tk::Dialog which creates its widget once and can be used many
times, the messageBox window is created every time it's used.
The following option/value pairs are supported:
-default
The case-sensitive symbolic name of the default button
for this message window ('Ok', 'Cancel' and so
on). See -type for a list of the symbolic names.
If the message box has just one button it will
automatically be made the default, otherwise if
this option is not specified, there won't be any
default button.
-icon
Specifies an icon to display. On X11 any of the builtin Tk bitmaps can
specified. On Windows only error, info, question or
warning are supported.
-message
Specifies the message to display.
-title
Specifies a string to display as the title.
-type
Specifies a predefined set of buttons to be displayed. The following
values are possible: 'AbortRetryIgnore', 'Ok', 'OkCancel',
'RetryCancel', 'YesNo' or 'YesNoCancel'.
