Hi,
Then I have a "second pass" in the caller function, where for programs which have a link, I would fetch the extra page, and call a second function, which will fill in the extra data (thankfully if pictures are present I only store their URL so it would stop there, no need for a third pass for pictures).
It annoys me that the first function returns "incomplete" objects... It somehow feels wrong.
I just realized i have the wrong way of thinking about it, in Haskell data is immutable therefore the first function wouldn't return incomplete "objects" that would be completed later: the second function will re-create completely the data anyway. So I would have duplicate data structures, once without the extra data, once with. Or something like that.
And otherwise I guess this is the policy when writing Haskell code: absolutely avoid spreading impure/IO tainted code, even if it maybe negatively affects the general structure of the program? There should be a reason for separating pure and impure code. If your code doesn't get easier to reason about or more reusable, than there's little reason for separation.
Yes.. I thought the goal is to strive for as much pure code as possible (which is easier to test and so on), but in this case (and obviously it's a small program) it doesn't seem tractable. I wonder what is the ratio pure/impure in bigger programs. Thank you... Emmanuel