Re: [boost] metactrl header [compile time asserts]

From: David Abrahams (abrahams_at_[hidden])
Date: 2000-07-23 11:44:12

I totally support all of Howard's arguments below :)

-Dave

----- Original Message -----
From: "Howard Hinnant" <hinnant_at_[hidden]>
To: <boost_at_[hidden]>
Sent: Sunday, July 23, 2000 11:32 AM
Subject: Re: [boost] metactrl header [compile time asserts]

> David Abrahams wrote on 7/23/2000 11:07 AM
> >Finally, I want to make a last-ditch plea to consider other naming
> >conventions than "meta_" for this stuff.
>
> Ok, I'll bite.  I see no need to prefix every compile-time computation
> object with "meta_" or "ct_" (or other similar conventions).  Compile
> time compuatation is evident from the syntax of its use.  type_traits.hpp
> is full of compile time compuations:
>
> remove_const
> remove_volatile
> remove_cv
> remove_pointer
> remove_reference
> remove_bounds
> remove_all
> is_same
> is_const
> is_volatile
> ...
>
> I would have strongly argued against:
>
> meta_remove_const
> meta_remove_volatile
> meta_remove_cv
> meta_remove_pointer
> meta_remove_reference
> meta_remove_bounds
> meta_remove_all
> meta_is_same
> meta_is_const
> meta_is_volatile
> ...
>
> It's just too wordy.  The prefix "meta_" hasn't conveyed any more
> information to me.  I know that is_const (for example) is a "meta"
> operation from the way I use it:
>
> bool b = is_const<T>::value;
>
> Similarly with IF:
>
> typedef IF<flag, type1, type2>::RET my_type;
>
> Ok, IF is a bad name (macro collision).  And "if" is a bad name (keyword
> collision).  "meta_if" or "ct_if" is not too bad, unless they are part of
> a grand scheme to blindly prepend every compile-time computation with
> "meta_" or "if_".  There are several other reasonable possibilities for
> this particlular construct than "...if...":
>
> typedef select     <flag, type1, type2>::type my_type;
> typedef choose     <flag, type1, type2>::type my_type;
> typedef choose_from<flag, type1, type2>::type my_type;
> typedef pick       <flag, type1, type2>::type my_type;
> typedef pick2      <flag, type1, type2>::type my_type;
> (thinking there might also be a pick3 where flag would take on 0, 1 or 2)
> typedef get_one_of <flag, type1, type2>::type my_type;
> typedef grab_one_of<flag, type1, type2>::type my_type;
> typedef decide_on  <flag, type1, type2>::type my_type;
> ...
> Ok, I'm getting punchy. ;-)  But hopefully my point is made:  The set of
> reasonable names is much bigger than "prefix_if".
>
> I argue similarly for the other recently discussed "meta" operations.
>
> -Howard
>
> ------------------------------------------------------------------------
> In Europe, more than 219 million people will access Internet services
> using mobile phones by 2003, according to Forrester Research.
> Learn Wireless Development on
> http://click.egroups.com/1/6222/4/_/9351/_/964366343/
> ------------------------------------------------------------------------
>
>