[Haskell-cafe] debugtracehelpers Re: traceM and traceShowM

[Alberto G. Corona]

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 <jgbailey at gmail.com>

> 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 <tphyahoo at gmail.com>
> wrote:
> > I have this and a couple other handy functions in
> >
> > DebugTraceHelpers:
> >
> >
> http://patch-tag.com/r/tphyahoo/DebugTraceHelpers/snapshot/current/content/pretty
> >
> > hackage:
> >
> >
> http://hackage.haskell.org/packages/archive/DebugTraceHelpers/0.12/doc/html/Debug-Trace-Helpers.html
> >
> >
> > 2009/10/16 Martijn van Steenbergen <martijn at van.steenbergen.nl>:
> >> Hello,
> >>
> >> I propose the addition of the following two functions to module
> Debug.Trace:
> >>
> >>> 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 at haskell.org
> >> http://www.haskell.org/mailman/listinfo/libraries
> >>
> > _______________________________________________
> > Haskell-Cafe mailing list
> > Haskell-Cafe at haskell.org
> > http://www.haskell.org/mailman/listinfo/haskell-cafe
> >
> _______________________________________________
> Haskell-Cafe mailing list
> Haskell-Cafe at haskell.org
> http://www.haskell.org/mailman/listinfo/haskell-cafe
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.haskell.org/pipermail/haskell-cafe/attachments/20091020/b56190ab/attachment.html