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Subject: Re: [geometry] How far should I expect to get with points that are "values"?
From: Patrick J. LoPresti (lopresti_at_[hidden])
Date: 2014-07-16 19:22:16

Barend Gehrels <barend_at_[hidden]> writes:

> Why is this not an option? You don't to have setters or getters. If
> you use this macro without the const, it just creates traits to get
> and set x,y directly.

Sorry; I did not explain myself very well. My actual code looks more
like this:

    struct MyPoint {
      // constructors, getters, etc. (but no setters)

      __m128i vec;

I was trying to provide a minimal compilable example to illustrate a
failure I was not expecting.

> The _CONST suffix means that the set part of the traits is not
> implemented. But Boost.Geometry can therefore not create any point
> then.

OK... But why not? Don't 2D points -- especially "value class" points --
generally have a constructor accepting the x,y components as arguments?

I suppose you do not want Boost.Geometry to assume that (?) But then a
lot of things in the library will never work with value classes.

> No, that is not necessary. It should work fine like this.

I guess I am curious what is the point (no pun intended) of
BOOST_GEOMETRY_REGISTER_POINT_2D_CONST if most of the algorithms are not
going to work with such points. Also I am curious how to know what I
should expect to work and not to work, apart from just trying it...


 - Pat

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