get-text-from-user in Dialogs

• (get-text-from-user title message parent init-val style) -> string or #f
   title : string
     message : string or #f
   parent = #f : frame% or dialog% object or #f
   init-val = "" : string
     style = null : an empty list of symbols

  Gets a text string from the user via a modal dialog, using parent as the parent window if it is specified. The dialog's title is title. The dialog's text field is labelled with message and initialized to init-val (but init-val does not determine the size of the dialog).

  The result is #f if the user cancels the dialog, the user-provided string otherwise.

  The style argument is provided for future extensions. Currently, style must be the empty list.