Re: [GD-General] Re: C++ turing complete

[Jesse J. <jes...@mi...>]

At 11:45 PM -0500 12/23/01, Patrick M Doane wrote:
>On Sun, 23 Dec 2001, Jesse Jones wrote:
>
>  > Well, there's a lot of value in being able to generate the code from
>>  within C++. It's more portable and convenient than using something
>>  like Perl and it's better integrated with the other parts of the
>>  language.
>
>There other ways to generate code besides Perl--consider a parser
>generator like Yacc.

Sure, but none of these are as tightly integrated with C++ as 
templates. This seems to me to limit their applicability. And, I'd 
note, that there are many more heavy duty template libraries than 
code generating systems like Yacc.

>One could probably implement this using template
>meta-programming techniques, but I'm sure that Yacc can give much better
>error messages and provides a syntax that is easier to use than templates.

Probably. If you haven't read it you might want to check out a book 
called "Generative Programming". It has several very interesting 
chapters including a good chapter on template meta-programming.

>Integration with the language is nice, but it's a pity that it comes at
>such a high price to the syntax.  This becomes especially noticeable when
>compared with similar systems in Lisp or Camlp4.

Yep, I think part of the problem was that templates were designed for 
things like containers and algorithms. From what I've read the 
functional programming aspects came as a surprise. The committee is 
talking about a few things like typeof that would make 
meta-programming a bit easier, but AFAICT it's going to remain an 
activity practiced by only a few people.

   -- Jesse