Files
gf-core/src/GF/System/Tracing.hs
2005-04-26 08:54:11 +00:00

74 lines
2.0 KiB
Haskell

{-# OPTIONS -cpp #-}
----------------------------------------------------------------------
-- |
-- Maintainer : PL
-- Stability : (stable)
-- Portability : (portable)
--
-- > CVS $Date: 2005/04/26 09:54:11 $
-- > CVS $Author: bringert $
-- > CVS $Revision: 1.4 $
--
-- Tracing utilities for debugging purposes.
-- If the CPP symbol TRACING is set, then the debugging output is shown.
-----------------------------------------------------------------------------
module GF.System.Tracing
(trace, trace2, traceM, traceCall, tracePrt, traceCalcFirst) where
import qualified Debug.Trace as Trace
-- | emit a string inside braces, before(?) calculating the value:
-- @{str}@
trace :: String -> a -> a
-- | emit function name and debugging output:
-- @{fun: out}@
trace2 :: String -> String -> a -> a
-- | monadic version of 'trace2'
traceM :: Monad m => String -> String -> m ()
-- | show when a value is starting to be calculated (with a '+'),
-- and when it is finished (with a '-')
traceCall :: String -> String -> (a -> String) -> a -> a
-- | showing the resulting value (filtered through a printing function):
-- @{fun: value}@
tracePrt :: String -> (a -> String) -> a -> a
-- | this is equivalent to 'seq' when tracing, but
-- just skips the first argument otherwise
traceCalcFirst :: a -> b -> b
#if TRACING
trace str a = Trace.trace (bold ++ "{" ++ normal ++ str ++ bold ++ "}" ++ normal) a
trace2 fun str a = trace (bold ++ fgcol 1 ++ fun ++ ": " ++ normal ++ str) a
traceM fun str = trace2 fun str (return ())
traceCall fun start prt val
= trace2 ("+" ++ fun) start $
val `seq` trace2 ("-" ++ fun) (prt val) val
tracePrt mod prt val = val `seq` trace2 mod (prt val) val
traceCalcFirst = seq
#else
trace _ = id
trace2 _ _ = id
traceM _ _ = return ()
traceCall _ _ _ = id
tracePrt _ _ = id
traceCalcFirst _ = id
#endif
escape = "\ESC"
highlight = escape ++ "[7m"
bold = escape ++ "[1m"
underline = escape ++ "[4m"
normal = escape ++ "[0m"
fgcol col = escape ++ "[0" ++ show (30+col) ++ "m"
bgcol col = escape ++ "[0" ++ show (40+col) ++ "m"