rate_stream::is_derivable

Source: stream/rate/rate_stream__is_derivable.pro

 rate_stream::is_derivable
        Return whether a rate stream is in a sufficiently processed
        state to generate the data of a derived stream.

 Usage:
        ok = strref -> is_derivable()

 Arguments: none

 History:
        Original: 10/4/02; SJT
        Modified to deal with UDS & Mag streams from old imports:
        26/4/02; SJT