-- Communicating Haskell Processes.
-- Copyright (c) 2008, University of Kent.
-- All rights reserved.
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-- This module contains a trace-type that does not record anything.  This is
-- generally not needed (just use runCSP without tracing) but is included in
-- the library for completeness.
module Control.Concurrent.CHP.Traces.TraceOff (TraceOff) where

import Control.Concurrent.CHP.Base
import Control.Concurrent.CHP.Traces.Base

import Text.PrettyPrint.HughesPJ

-- | A trace type that does not record anything.
newtype TraceOff a = TraceOff ()

instance Show (TraceOff a) where
  show = const ""

instance Trace TraceOff where
  runCHPAndTrace = runCHPProgramWith NoTrace (const $ TraceOff ())
  emptyTrace = TraceOff ()
  prettyPrint = const empty
  labelAll = const emptyTrace