intersect_subregion
  
  Description:
  public Region? 
intersect_subregion (
TextIter _start, 
TextIter _end)
  
 
  
    Returns the intersection between this and the subregion delimited by @_start and @_end.
    this is not modified.
    Parameters:
    
      
        | this | 
        
           a Region. 
         | 
      
      
        | _start | 
        
           the start of the subregion. 
         | 
      
      
        | _end | 
        
           the end of the subregion. 
         | 
      
    
    Returns:
    
      
        | 
           the intersection as a new  Region. 
         |