On Tue, 2009-10-20 at 15:45 +0100, Simon Marlow wrote:
I've not yet seen anyone put forward any practical programs that have confusing behaviour but were not written deliberately to be as wacky as possible and avoid all the safety mechanism.
The standard use case for hGetContents is reading a read-only file, or stdin where it really does not matter when the read actions occur with respect to other IO actions. You could do it in parallel rather than on-demand and it'd still be ok.
There's the beginner mistake where people don't notice that they're not actually demanding anything before closing the file, that's nothing new of course.
If the parallel runtime reads files eagerly, that might hide a resource problem that would occur when the program is run on a sequential system, for example.
That's true, but we have the same problem without doing any IO. There are many ways of generating large amounts of data. Duncan