What library functionality would you most like to see in D?

[Jonathan M Davis]

On Sunday 31 July 2011 22:28:51 Johann MacDonagh wrote:
> On 7/31/2011 9:56 PM, Jonathan M Davis wrote:
> > If we do a hand-written lexer of D for Phobos, it really should be a
> > fairly direct port of the dmd front-end. It should be _somewhat_
> > D-ified as appropriate, (and the API should definitely be properly
> > range-based and all that), but the implementation needs to be fairly
> > close to dmd itself so that it's easy for someone to port changes and
> > fixes back and forth between the two. Otherwise, they're going to get
> > out of sync fairly easily. If we're not going to do a direct port, then
> > we might as well just do the template-based lexer generator that Andrei
> > and others would really like to see (which we should still do, but I
> > think that the hand-written lexer is nowhere near as valuable if it's
> > not a direct port of dmd's lexer).
> 
> Yeah, I get the point, but I feel that I could port most trivial changes
> from DMD's lexer to lexer.d. The layout of the code is different, of
> course, but I'm borrowing most of the lexing logic from DMD. Plus with
> unittests, I think we could ensure things are lexing the same.
> 
> > Also, I see _zero_ value in making it support D1. If it's for D2's
> > standard library, then what's the point of it lexing D1? That just
> > complicates the lexer for what is essentially a legacy product. And
> > given that the differences between D1 and D2 in dmd's lexer are covered
> > with #ifdefs, it would be rather complicated to try and do a direct
> > port which covers both D1 and D2. It would probably be easier if the
> > two were completely separate.
> 
> Well, it doesn't appear that there are that many lexical differences
> between D1 and D2. A few operators, a few keywords, D2 supports a few
> different string constants, etc...
> 
> I wanted this to be usable by IDEs. Do we not want to support D2 for
> development? I could certainly make this D2 only.
> 
> > As for what I've done so far, I'd have to go look. I haven't touched it
> > in a couple of months, I expect. There has been a lot of other stuff
> > that I've needed to do, and Andrei was trying to discourage such an
> > implementation the last time that I brought it up. So, I haven't
> > exactly been in a rush to get it done. I'd like to do it, but I've been
> > rather busy.
> 
> Well, if Andrei wants to flex the power of D2's templates / etc... with
> a parser generator then maybe we should go down that route. Andrei, what
> do you think? Would the lexer/parser be generated at compile time or a a
> regular tool that would generate the appropriate D files?
> 
> > So, if you really want to work on a potential D lexer for Phobos, that's
> > fine, but I really think that it needs to be a rather direct port, and
> > that doesn't sound like what you've been doing.
> > 
> > - Jonathan M Davis
> 
> If we decide to scrap my idea and go a more generic route, I'd probably
> start working on a standard database interface. I'd like to see D become
> a little more web framework friendly, and a nice generic database
> interface is definitely a start.
> 
> So, Andrei, what do you think about a lexer / parser in Phobos? Generic
> or a straight port?

I can tell you right now that he wants a generic, template-based lexer / 
parser generator rather than a hand-written solution. He doesn't like the idea 
of the hand-written solution. And I definitely think that we should have a 
template-based lexer / parser generator. The question is whether it's also 
worth having a hand-written port of the dmd front-end's lexer and parser to 
Phobos so that we can have on official lexer and parser in Phobos which parse D 
the same way that the compiler does.

- Jonathan M Davis