more unsafePerformIO questions (is it safe to use with ReadMode Handles)?

[Ganesh Sittampalam]

On Tue, 19 Aug 2003 10:52:57 +0100, "Simon Marlow" <simonmar@microsoft.com>
wrote:

>> Isn't there the possibility of inlining causing a read to 
>> happen twice even if it only appears to happen once?
>
>In theory that would be a valid transformation, but in practice no
>compiler would duplicate arbitrary computations.  GHC certainly doesn't.

I was thinking of a situation like 

let x = unsafePerformIO readFooFromDB in x+x

I see from your "Secrets of the GHC inliner" paper that x wouldn't be
inlined by GHC, but it seems to me like a serious abuse of the principle of
referential transparency to write programs that _assume_ that.

Cheers,

Ganesh