[racket] testing impure stuff

On Mon, 23 Dec 2013 20:51:16 -0600
Robby Findler <robby at eecs.northwestern.edu>
wrote:

> I don't think the proposed fix would "resist" in this manner. The
> directory could be deleted between the time you check for its
> existence and when you ask for its contents.
> 

I would differentiate between static and dynamic errors.

Static error is that a directory couldn't be traversed because of
permission denied. An optional parameter would do.

Dynamic error is that during traversing a bad thing happens.
Permissions gets changed or even the directory gets deleted. In this
case it is an exception, and in-directory stops. However, the issuer of
in-directory should have an option to resume.


-- 
Manfred



> 
> 
> On Mon, Dec 23, 2013 at 7:05 PM, Matthias Felleisen
> <matthias at ccs.neu.edu>wrote:
> 
> >
> > If you don't have permissions, you can't recur and the current
> > implementation throws an error w/o recourse to a fix. As Manfred
> > points out, this is a 'fair weather' function. A real
> > implementation should resist such external mishaps. But I also
> > agree w/ you about the parameter. It would generalize this
> > situation -- Matthias
> >
> >
> >
> >
> >
> >
> > On Dec 23, 2013, at 5:53 PM, Robby Findler wrote:
> >
> > Perhaps in-directory can take an optional parameter that controls
> > whether or not to recur?
> >
> > Robby
> >
> >
> > On Mon, Dec 23, 2013 at 4:42 PM, Matthias Felleisen
> > <matthias at ccs.neu.edu>wrote:
> >
> >>
> >> On Dec 23, 2013, at 5:12 PM, Manfred Lotz
> >> <manfred.lotz at arcor.de> wrote:
> >>
> >> > I think in-directory should be fixed in the long run.
> >>
> >> Agreed. -- Matthias
> >>
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> >
> >
> >
>