[boost] Re: N-arity operators in C++, also reducing temporaries. [Repost]

From: Larry Evans (cppljevans_at_[hidden])
Date: 2005-03-08 14:23:48

On 03/08/2005 06:26 AM, Tobias Schwinger wrote:
[snip]
> I use 'apply', 'apply_one' and 'apply_but' functions that allow me to 
> apply functors to all elements, one element and all but one elements, 
> respectively (I use different versions for both static and dynamic 
> indices and both static and dynamic functors):

What does "static" and "dynamic" mean here?  Does static mean
"evaluable at compile time" and "dynamic" means otherwise?

[snip]

> - Do you know the Boost.Assign technique ?
> I use a similar approach to have a nice syntax for initialization and 
> inlining that works within expressions:
> 
>   my_quaternion = n_x * sin_half_a
>                 , n_y * sin_half_a
>                 , n_z * sin_half_a
>                 , cos_half_a;
> 
> and
> 
>   vector_slice<0,3> (my_quaternion)
>     = (vec_inl| n_x,n_y,0.0) * sin_half_a;
> 
Never seen this (vec_inl| n_x,n_y,0.0).  Looks like
a set expression or lambda expression.  Could you
provide a reference.  I searched:

http://www.boost.org/libs/assign/doc/index.html#reference

for the character '|' but got no results.

> 
> 
> ( The 'my_quaternion' variable from the examples is a four-dimensional 
> vector, _not_ a boost::quaternion. )
> 
Does "four-dimensional" mean "length is four" or "accessing a scalar
requires four indices passed to the operator()", e.g.

   my_quaternion(0,2,1,1)

or something similar (I want to call the above operator() the
the index operator, but can't for obvious reasons) ?
[snip]