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I really don't understand what you're trying to get at in #4. Sure, you can view a changing variable as a function of time, keeping a list of the changes. But the point of FP is that it makes explicit that you've got that list of changes; you can no longer ask for "the value of x" at get one of the many values; you have to ask for "the value of x at time t," which forces you to change your design, sure, but gives you the benefit that "the value of x at time t" will always be the same, everywhere in the program. It's basically brought out into the open what was once a piece of hidden state about x (time).

I sense from your comments about integers and Church's thesis that you're pointing out that something different goes on under the hood than what you really see. If that's the case, sure, but that's the *whole point*.

To go back to the simple example, yes, we all know what happens in C when you try to assign 2^32+1 to a 32-bit unsigned integer. That's bad. Thats why in many, many languages (I'll use Ruby as an example, since I know it reasonably well) we don't usually deal with what's actually going on inside the box when we maniuplate integers. If in ruby I say "3 + 2" I get "5", and it's probably doing 32-bit integer arithmetic. If I say "2 << 35", the numbers may well be 32-bit integers internally, but certainly the result isn't. Yet everything continues to work; I get the right answer and I can use it in further calculations. It's all kept under the hood. I can reason much more easily about my program because I don't have to worry about integers being bigger or smaller than a certain size.

That, it seems to me, is the whole point of FP; it's to make it easy to reason about your programs by putting certain constraints on them and hiding certain things you don't want to worry about. This process was started a long time ago by doing things like replacing dynamic with lexical scoping (BTW, hello? Who, besides perl, uses dynamic scoping nowadays?).

So I really don't see the point of this rant. When you take out the "it's hidden but I'll look at it anyway," stuff, the dynamic scoping straw man (nobody forces it, and neither Haskell nor Scheme nor many others even support it!), and the "this was made explicit but I'll pretend that that wasn't the whole point" stuff, there doesn't seem to be much left here.

In reply to #4 Confuses Me by Anonymous Monk
in thread pissed off about functional programming by mstone

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