[Haskell-cafe] global, modifiable variable for debugging
pumpkingod at gmail.com
Sun Dec 26 23:10:16 CET 2010
Seems like you'd want x <- getArgs and x == ["debug"] rather than the
irrefutable pattern match.
On Sun, Dec 26, 2010 at 3:04 PM, Michael Snoyman <michael at snoyman.com>wrote:
> I think something like this would work:
> myFlag = unsafePerformIO $ do
> [x] <- getArgs
> return $ x == "debug"
> In general, unsafePerformIO should be avoided, but this is one of
> those situations where we can give you a pass ;).
> On Sun, Dec 26, 2010 at 9:53 PM, <briand at aracnet.com> wrote:
> > Hi,
> > I have a program with a debug flag in it (Strangely I've yet to be
> > able to write bug-free code). I'd like to change the state of the
> > debug flag based on command line args.
> > I looked at IOVar but that would cause all the pure procedures to get
> > swallowed by the IO Monad.
> > Is a better way to get this behavior ?
> > Thanks,
> > Brian
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