Compile time function execution...

[Bill Baxter]

Walter Bright wrote:
> Walter Bright wrote:
>> This should obsolete using templates to compute values at compile time.
> 
> For contrast, compare with the C++ proposal:
> http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2006/n1972.pdf

It's kinda long and boring, but it looks like the key differences are

1) The need to tag compile-time functions with a new keyword, 
"constexpr", though they seem to sell this as an advantage.  "a 
programmer can state that a function is intended to be used in a 
constant expression and the compiler can diagnose mistakes." -- page 9.

2) The restriction that a constexpr function can only contain "return" 
followed by exactly one expression.  No loops for you!  And I hope you 
like quadruply nested b?x:y expressions!

That's just a proposal, though, right?  Has it been accepted for C++09? 
   Seems like a hard sell given the limitations and the new keyword.

--bb