[jhc] Monad.ST

Henning Thielemann jhc at henning-thielemann.de
Sun Nov 15 18:01:25 EST 2009

On Sun, 15 Nov 2009, Isaac Dupree wrote:

> hmm, I looked at the code. I don't quite understand lazy ST, but I don't 
> think that version you made is correct.  The writes (and reads) really may 
> not be re-ordered based on which data is demanded when.  I think the 
> distinctive thing about lazy ST is that the whole computation doesn't have to 
> be executed before returning a result (so you can return an infinite 
> list/computation, like, do{ a <- something; as <- recur; return (a:as) } ). 
> But I can't figure out how to implement the correct behavior... (or if I'm 
> just confused)...

Thank you for spotting the problem so quickly. I have pushed a patch that 
hopefully solves the problem.

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