On 8/10/2012 5:19 PM, David Piepgrass wrote:
Your version is basically a very long-winded way to say "auto x = 5 - (3 + 1);"
so it really has nothing to do with the example.
The point of the example was to represent a simple AST and store it on the
stack, not to represent + and - operators as plus() and minus() functions.
I see that now, and I presented a D way of doing it using "expression
templates", a technique pioneered by C++ programmers.
Expression templates have been used before in D, in particular to implement a
regular expression engine. Dmitry Olshansky has since shown how fantastic this
is for generating incredibly fast regex engines.
As far as I know, only C++ and D have sufficiently powerful abstraction
mechanisms to make this possible.
Really? And here I genuinely thought D was good enough for all the things C and
FORTRAN are used for.
If you're going to write C code, use a C compiler. It's possible to use D as a C
compiler, but kinda pointless except as a transitory state towards using D
capabilities.
I hope someday to have a programming system whose features are not limited to
whatever features the language designers saw fit to include -- a language where
the users can add their own features, all the while maintaining "native
efficiency" like D. That language would potentially allow Rust-like code, D-like
code, Ruby-like code and even ugly C-like code.
I guess you don't want to be the one to kickstart that PL. I've been planning to
do it myself, but so far the task seems just too big for one person.
Andrei originally proposed to me a language like that. I talked him out of it
:-)
