[Haskell-cafe] the Haskell "with" "pattern"?

[Johan Tibell]

On Wed, Aug 6, 2008 at 5:44 PM, Jules Bean <jules at jellybean.co.uk> wrote:
> Johan Tibell wrote:
>> You probably knew this already but there's nothing in the "with idiom"
>> that prevents the resource to escape.
>
> And, it doesn't always matter. Some withs are more unsafe that others :)
>
> if the 'with' constructs a nice ordinary heap allocated haskell structure
> from the external resource then it may not matter one jot if it escapes: it
> may be out-of-date, perhaps, but still a useful data value.

I'm sure you're right but at the moment I can't really think of any
such structure. Perhaps you could give an example? Why would you need
the "with" in the first place for such a structure?

Cheers,

Johan