ask for saving modified editor files if octave is closed (bug #38689) * files-editor-tab.cc(constrctor): init new flag indicating if app is closing, (check_file_modified): message box is modal if app is closing, no cancel, parent of box is the editor's tab widget for a correct palcement of the box, (conditional_close): new second arg: flag for closing app (default false), it is stored in the tab's class wide flag * file-editor-tab.h: second arg for conditional_close and new class wide flag * file-editor.cc(destructor): sending close requests to all editor tabs with flag indicating the application is closing (add_file_editor_tab): new arg for fetab_close_request and conditional_close * file-editor.h: new 2nd arg for fetab_close_request (closing app, def. false) * main-window.cc(destructor): delete editor window first for showing the message boxes for modified editor files in front of a complete gui

## -*- texinfo -*-
## @deftypefn  {Function File} {} polynomial ()
## @deftypefnx {Function File} {} polynomial (@var{a})
## Create a polynomial object representing the polynomial
##
## @example
## a0 + a1 * x + a2 * x^2 + @dots{} + an * x^n
## @end example
##
## @noindent
## from a vector of coefficients [a0 a1 a2 @dots{} an].
## @end deftypefn

function p = polynomial (a)
  if (nargin == 0)
    p.poly = [0];
    p = class (p, "polynomial");
  elseif (nargin == 1)
    if (strcmp (class (a), "polynomial"))
      p = a;
    elseif (isvector (a) && isreal (a))
      p.poly = a(:).';
      p = class (p, "polynomial");
    else
      error ("polynomial: expecting real vector");
    endif
  else
    print_usage ();
  endif
endfunction