; docformat = 'rst'
;+
;There is a open-source Matlab clone, Octave, which is not as good as it could be
;because it is too slow. One of the reasons it is slow is that it checks the
;date of every .m file every time its function is called, to see if it has
;changed. We keep this cache so that we don't have to call file_test thousands
;of times
;
; :Examples:
;   cache = has_astron_lib()
;-
;+
; :Returns:
;   Returns (1) if the cache is installed, (0) if the cache has not. 
;-
function has_astron_lib

  common has_astron_lib_common,cache
  if n_elements(cache) eq 0 then cache=file_test(!astron_lib_path)

  return,cache
end