\subsubsection{TieOff}
\index[typeclass]{TieOff}
\label{lib-tieoff}

{\bf Package}
\index{TieOff (package)}


\begin{verbatim}
import TieOff :: * ;
\end{verbatim}



{\bf Description}

This package provides a typeclass \te{TieOff\#(t)} which may be
userful to provide default
enable methods of some interface \te{t}, some of which must be
\te{always\_enabled} or require some action.


{\bf Typeclasses}

\begin{verbatim}
typeclass TieOff #(type t);
  module mkTieOff#(t ifc) (Empty);
endtypeclass
\end{verbatim}


{\bf Example: Defining a \te{TieOff} for a \te{Get} interface}

This is a  sink module which pulls data from the \te{Get}
interface and displays the data.

\begin{verbatim}
instance TieOff #(Get #(t) )
  provisos (Bits#(t,st),
            FShow#(t) );
  module mkTieOff ( Get#(t) ifc, Empty inf);
     rule getSink (True);
        t val <- ifc.get;
        $display( "Get tieoff %m", fshow(val) );
     endrule
  endmodule
endinstance
\end{verbatim}