%
% stack: neg-time-str
%
"-" empty replall
%
% this should be a normal formatted time
%
" " 0 2 1 parse
%
% stack: hours mins
%
any?
{
 dup numeric
 {
%
% proper numeric minutes
%
  dup 60 lt
  {
   *datenowr
   _hours &":" _minutes 2 prezero &
   &
   !subtime

   !minutes
%
% analyze the hours
%
   dup numeric
   {
%
% proper numeric hours
%
    !hours
    _subtime
    _hours 60 mul _minutes add minus
    "n" Time.Add
    Time.Timels pop !minutes !hours
   }
   {
%
% not proper hours
%
    pop
   } ifelse
  }
  {
%
% not a proper minutes value
%
   pop2
  } ifelse
 }
 {
%
% not a proper number for minutes
%
  pop2
 } ifelse
}
{
%
% no minutes
%
 pop
} ifelse