Craig Dickson wrote:
> Why do you find this makes a significant difference? Personally, I find
>
> f x = ... f (x - 1)
>
> much more intuitive than
>
> f (x + 1) = ... f x
>
> I see no advantage in the n+k version.
>
>
I agree. n+k patterns make sense for a type of Natural Numbers (including 0),
but not for general Integral types.
They are also dangerous because they are defined in terms of < and -, which,
in a user-defined type, need not obey the usual laws, e.g. you cannot assume
that 0 < 1 holds.
The problem is that dropping them would break lots of stuff - but probably
more textbooks than programs.
--brian
