[Haskell-cafe] Progress indications

[Andrew Coppin]

Brandon S. Allbery KF8NH wrote:
>
> On Nov 29, 2007, at 17:13 , Thomas Hartman wrote:
>
>> but there's no risk using trace is there?
>
>
> If you're doing any other I/O, you may be surprised by where the trace 
> output shows up relative to it.
>

How about if the "I/O" is to write to a different stream? Then it 
wouldn't matter too much. Or perhaps updating a real progress bar widget 
on a GUI. Or - better still - frobnicate an MVar or something. (Then you 
can handle what you do with these "update" signals somewhere else 
without cluttering the main algorithm too much...)