Re: [boost] [time_series] Review

From: Steven Watanabe (steven_at_[hidden])
Date: 2007-08-13 14:18:34

AMDG

Eric Niebler <eric <at> boost-consulting.com> writes:

> I disagree with this. If anything non-trivial is going on in commit(), 
> then the second version cannot be *efficiently* implemented in terms of 
> the first, which means the second is necessarily the more primitive of 
> the two.

If anything interesting is going on in commit()
then neither one can be implemented efficiently
in terms of the other.  I was a bit unclear.  I
thought that buffering was the only reason for
using the second form. Thus, I envisioned

template<class T>
struct get_buffer_type {
    typedef no_buffer type;
};

template<bool>
ordered_assign_impl;

template<class T>
struct ordered_assign :
  ordered_assign_impl<
    is_same<typename get_buffer_type<T>::type, no_buffer>::value
  >::template apply<T> {};

template<>
struct ordered_assign_impl<true> {
  //use push_back
};

template<>
struct ordered_assign_impl<false> {
  //use a range assignment.
};

> The inserter design (with commit()) came out of a design discussion with 
> Dave A., which I took the time to review this morning. He was coming at 
> the problem from the perspective of MTL4 -- matrices and vectors. For 
> MTL4, he wanted generic ways of representing sparse data and of building 
> sequences. We wanted a mechanism that was general. He imagined a desire 
> to temporarily violate the invariants of a sequence while building it, 
> and then using commit() to "make it good".
> 
> <snip>

I see.  The inserters make a lot more sense in
a larger context.

In Christ,
Steven Watanabe