On Thu, Sep 3, 2009 at 12:59 PM, OvermindDL1<overminddl1@gmail.com> wrote:
On Thu, Sep 3, 2009 at 3:45 AM, Richard Webb<richard.webb@boldonjames.com> wrote:
OvermindDL1 wrote:
Slightly off-topic, but I consider D to be a *fascinating* language, kind of like how C++ should have been. It would actually be *much* easier to create Spirit in D then it would have been in C++, and you could have used real PEG syntax instead of C++/D'ifying it.
I've been looking at D a bit myself recently, and i just saw this on the D mailing list: http://lists.puremagic.com/pipermail/digitalmars-d-announce/2009-August/0139...
<still off-topic>
Heh, interesting, but they are going about it the completely wrong way. First Spirit 1's design is quite a bit more convoluted then Spirit2's. Second, thanks to mixin's and the fact that templates can operate on strings in D (not just integers and types like in C++), they could implement a *real* PEG syntax that gets completely lowered to pure D code at compile-time.
Yes, D is that powerful. Heck, if C++ added D style templates and mixin support and compile-time functions (which I guess is kind of getting added to C++1x), I would be happier then you could believe. :)
For an example, I even saw a pure compile-time regex parser that you use like: static_regex!("gh.+a") r; regex_info info = r(someString);
In D a template is !() unlike in C++ where it is <>. I personally like <> better since I am used to it, but !() is certainly easier to parse and is unambiguous... But yes, that regex is completely lowered to pure D code at compile time, ala Boost.Xpressive's static regex parser.
D really does mix in a lot of LISP's power into a C++ syntax (not all of LISP's power, but it gets *REALLY* close). _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost
(further continuing the off-topic trail here) For what it's worth, I've written a proof-of-concept compile-time recursive descent string parser in pure C++: http://arcticinteractive.com/2009/08/15/cpp-compile-time-string-parser-proto... It even comes with a static regex string to Xpressive transformation grammar (through a layer of indirection) :) although it's currently limited to MPL strings, so the syntax isn't as pretty as it could be with C++1x user-defined literals. Just shows that it is possible to do even with "vanilla" C++. Best regards, Tor Brede Vekterli