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From: Weapon Liu (weapon.liu_at_[hidden])
Date: 2006-12-14 09:15:16

John Maddock wrote:
> I have a piece of boilerplate code that accepts a tuple (of any size) and
> prints out either a csv file or a boost::array C++ code conaining the data
> passed.
> It allows me to output data for graphing, or matrixes of test data very
> quickly just by creating a short function that returns a tuple, and then
> passing that function to my boilerplate. If I want more columns of data I
> just increase the size of tuple by 1.
> I suppose I could have used a vector instead, but it's less elegant somehow.
> I've also used tuples in place of struct's whenever I have an API that needs
> to return more than 2 items. For example I have some root finding
> algorithms that accept a unary functor whose root is to be found: the
> functor returns a tuple containing the function evaluation, plus the first
> two derivatives. Using a tuple here simplified both implementation and
> documentation. Had I felt the need, I could have performed compile time
> dispatch to different algorithms based on how many derivatives were
> available (the tuples size).
Thanks John, that's very informative. Although a little bit of code
would be excellent :-)

I do have a question about the second application, I mean, don't you
have to wait until runtime to know how many derivatives a function
actually have? Or is it just that it can be known in the very scenario
you mentioned?

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