On 2/28/12 12:46 PM, Martin Nowak wrote:
I wrote a generic lexer generator some time ago.
It already let to some compiler O(N^2) optimizations, because the token
declarations sneak into the mangling :(.
I also finally added a workaround for a remaining CTFE bug (#6815).
https://gist.github.com/1255439 - lexer generator
https://gist.github.com/1262321 - complete and fast D lexer
Wow, now we have an embarrassment of riches!
I've ditched an attempt to write a parser combinator. It was based on
expression templates and ended up at spirit craziness.
I'm not sure what a parser combinator is. I think grammar inheritance
could actually be interesting to explore.
<PERSONAL OPINION
The hassle of providing good error messages and synthesizing parse results
in a generic parser outweigh the benefit of a declarative grammar.
/PERSONAL OPINION>
I think synthesizing ASTs is a solved problem, see my post before. Error
messages are still a hassle, but I missed the point they became good in
hand-written parsers :o).
A lot becomes feasible from the CTFE perspective,
despite some bugfixes I only miss exp and log currently.
I do not agree that it's the right moment to write a parser though.
It hits the first of phobos two biggest shortcomings, the lack of a good
I/O
system and the missing Allocators.
Any parser written now will either risk to not play nice with ranges
or has to come up with it's own buffering again.
Agreed, but that doesn't seem like the largest hurdle to me.
Andrei
