On 6 Feb 2008, at 7:30 PM, Uwe Hollerbach wrote:
Hi, all, thanks for the responses. I understand the distinction between pure functions and impure functions/procedures/IO actions,
Um, I'm not sure of that, given what you go on to say.
it just felt to me in the samples that I quoted that I was in fact starting from basically the starting point,
Not really. The key difference to understand is that between difference between getCurrentTime and toUTCTime 42. These are your `starting points' --- the rest is just pure code.
eventually getting to the same endpoint (or at least a pair of endpoints that are not easily distinguished from each other by looking just at code), and inbetween
Well, the in-between paths are pure (or can be) either way. It's the starting point that needs liftIO or not.
one path was going through liftIO and the other not. But I guess it comes down to the fact that, since I'm in a REPL, I'm wallowing in impurity all the time (or something like that :-) )
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