Anyone interested in a Spirit for D?

Walter Bright newshound at
Wed Oct 18 14:12:41 PDT 2006

Bill Baxter wrote:
> But given Don's experiments with compile-time text parsing in D, it's 
> conceivable that in D the above parser could just be created with:
>    r = make_parser("real_number (',' real_number)*");
> I.e. use the EBNF version directly in a string literal that gets parsed 
> at compile time.
> That would be pretty cool.

Yes, it would be. But there's a catastrophic problem with it. Spirit 
enables code snippets to be attached to terminals by overloading the [] 
operator. If the EBNF was all in a string literal, this would be impossible.

> Though, you know, even thinking about Boost::Spirit, I have to wonder if 
> it really is necessary.  From the intro it says that it's primary use is 
> "extremely small micro-parsers", not a full blown language processor. 
> But if that's the target then the runtime overhead of translating the 
> EBNF description to a parser would be pretty trivial.  So I guess the 
> real benefit of a compile-time parser-generator is that your grammar can 
> be _verified_ at compile-time.

I disagree. I think the real benefit is avoiding reliance on an add-on 
tool. Such tools are a nuisance; making archival, maintenance, etc., clumsy.

> At any rate the Spirit documentation seems to be rife with juicy 
> comments of the form "yes it looks funky, but we're stuck with C++ 
> here".  So it's a good place to get ideas for how to make things better.


More information about the Digitalmars-d mailing list