[boost] Re: mpl functions, pow_, root_, reciprocal

From: Andy Little (andy_at_[hidden])
Date: 2004-02-01 18:27:41

"David Abrahams" <dave_at_[hidden]> wrote ...
> "Andy Little" <andy_at_[hidden]> writes:

[snip]

> > OK I have started on boost::mpl::rational_c.
> > I have derived from that into boost::mpl::integral_rational_c.
>
> I can't imagine what that would mean or why that would be needed.  A
> rational number is by definition both:
>
>      a. Not integral
>      b. A ratio of integers.

That was a bait.;-) OK to hack Alexey Gurtovoys rational_c ?
This message has been recorded etc.

>
> > In implementing that I need some promotion...so may try Fernando
Cacciolas
> > converter. OTOH Alexey Gurtovoys types_promotion_traits if all needs to
be
> > mpl.
>
> I think you want Joel de Guzman's technology.  You might search the
> message archives for his postings about it.

OK  I need this in the library...btw so does mpl impl ! too much ad-hoc
stuff for my likeing :-)

[snip]

> >>From there I go to int_rational, long_rational etc
> > I prefer   int_rat but.... ok forget it :-)
>
> Overkill, IMO, but it's your party.

I'll make sure I go to bed early . :-)

>
> > Finally can use that to implement  simple pow,root reciprocal etc.
> > Should I do  reciprocal<integral_c> --> integral_rational_c or is that a
> > user thing?
>
> Sorry, I don't understand the question.

sorted by your previous reply.

> MPL metafunctions only deal in types (which may be wrappers for
> numbers).  That simplifies everything a lot.

I'm going for naming members xx_value and xx_type.
Any good ?... whats (rolling up my trouser leg) *traditional*.

[snip]

> > Are there some written guidelines on these conventions or am I just
meant to
> > 'know' them? hmm..I seem to remember asking this before :-)
>
> Just look back a little bit in the thread to Daniel Wallin's posting
> and I think you'll find the answer you seek.

This ?  :
"

This is not the "traditional" use of trailing underscores. Normally they
are used for keywords.

   int -> int_
   bool -> bool_

etc. MPL uses tons of names that clashes with names in std. This is a
problem for the user, not the library.

-- 
Daniel Wallin
"
Cant see the reference or the link to written guidelines ...?
I do see ... "Dont worry about the user" though !
hmm ...Ok to use the _t suffix then ..."traditional" way to represent a
typedef . Started in the 70's I think ;-)
BTW I declined joining the freemasons ...I prefer things to be open  to
everybody.
BUT .......... mpl rocks! ..........................  :-)
regards
Andy Little