I don't know why people use trace this way instead of in the reverse form: debug = flip trace this way I can isolate debug code in the right from normal code: main= do a <- getChar b <- getChar `debug` ("a="++ show a) let c= a+b `debug` ("b="++ show b) ... and so on. I saw it for the first time in the DrIFt libtary. 2009/10/20 Justin Bailey

These woudl be much more useful if they flushed the output handle after each message. Then you know your trace messages will be displayed/written to a file.

On Mon, Oct 19, 2009 at 1:51 PM, Thomas Hartman wrote:

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I have this and a couple other handy functions in

DebugTraceHelpers:

http://patch-tag.com/r/tphyahoo/DebugTraceHelpers/snapshot/current/content/p...

...

hackage:

http://hackage.haskell.org/packages/archive/DebugTraceHelpers/0.12/doc/html/...

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2009/10/16 Martijn van Steenbergen :

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Hello,

I propose the addition of the following two functions to module

Debug.Trace:

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...

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traceM :: Monad m => String -> m () traceM msg = trace msg (return ())

traceShowM :: (Show a, Monad m) => a -> m () traceShowM = traceM . show

These functions allow tracing in any do-block. I often define them

myself; I

...

think they are useful in general.

Deadline: 23 October 2009.

Martijn. _______________________________________________ Libraries mailing list Libraries@haskell.org http://www.haskell.org/mailman/listinfo/libraries

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