CTFE vs. traditional metaprogramming

[Don]

language_fan wrote:
> Sat, 10 Oct 2009 10:26:11 +0200, Don thusly wrote:
> 
>> CTFE doesn't mean "string mixins using CTFE". It just means CTFE. (BTW
>> you can do string mixins with templates only, no CTFE, if you are
>> completely insane).
> 
> CTFE without mixins is rather limited form of metaprogramming. You can 
> basically only initialize some static non-code data, and not much more. 

That's a lot, though. For example, you can perform the compilation step 
for a regexp, and determine whether it needs to be implemented with 
backtracking, or not. CTFE is perfect for parsing DSLs.

> String mixins with templates was the only way to go before CTFE became 
> possible -- those were the times!

They were very short times <g>. String mixins were introduced in 
DMDD1.005, (5 Feb 2007) and CTFE came in 1.006, ten days later.
But that was indeed a very fun time for D.

I did a lot of early metaprogramming work with template value 
parameters, before string mixins. It was quite ugly, and painful to 
write. D metaprogramming techniques have gradually got less hacky over time.