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From "Nathan Beyer" <nbe...@gmail.com>
Subject Re: What should we choose for Harmony: JavaCC or AntLR? Was: Google Summer of Code and Harmony
Date Sat, 29 Mar 2008 16:49:23 GMT
Neither would be my preference. Parser generators have their value,
but low-level frameworks, containers and runtimes should avoid as many
dependencies as possible, and these are just convenience tools, which
I think are only useful as temporary solutions for Harmony.

As for RTF in particular, I believe you'll spend just as much time
working out a grammar and helper methods for a parser generator as you
would implementing a custom parser. RTF is a nasty, nasty thing.

-Nathan

On Sat, Mar 29, 2008 at 9:28 AM, Alexei Fedotov
<alexei.fedotov@gmail.com> wrote:
> Hello, Aleksey,
>
>  This is a good question indeed. Currently both popular parser
>  generators, i.e. JavaCC and ANTLR, are used in Harmony. We have to
>  decide which one is the preferable one for your project and overall. I
>  believe people who have some experience may help us to decide what
>  suits RTF parser and Harmony better. For your application you may just
>  note that you are collecting arguments to choose one generator from
>  two to be most applicable for Harmony instead of naming the only one,
>  and list the arguments you have already collected.
>
>  The licensing of both generators is acceptable. I have heard recent
>  talks about incompatible change of AntLR license, and cannot confirm
>  that. It seems that AntLR 3.0 uses conventional BSD license [1].
>  JavaCC has a proprietary origin [2], but Sun does not claim its rights
>  for this generator.
>
>  There was a conflict between ANTLR from our boot class path and the
>  one from Dacapo benchmark. I don't think this should be a problem for
>  RTF parser: one can load classes into another class loader. Vladimir
>  Beliaev, Paulex and Alexey Varlamov have to say more about this [3].
>  From the other side people said that ANTLR provides more
>  understandable syntax that JavaCC [4], and AFAIK your mentor devoted
>  his university studies to ANTLR.
>
>  Alexei, all, do you have a parser generator preference?
>
>  [1] http://www.antlr.org/license.html
>  [2] http://markmail.org/message/v62n2jt7hvb234fi
>  [3] http://markmail.org/message/ja64toonfbo26yz5
>  [4] http://www.theserverside.com/news/thread.tss?thread_id=45464#233154
>
>
>
>  On Sat, Mar 29, 2008 at 2:01 AM, Aleksey Lagoshin <ayzen.quwe@gmail.com> wrote:
>  > Thanks for links and additional information.
>  >
>  >  I noticed that CSS parser is created by JavaCC. As far as I know there is
>  >  another one parser generator - ANTLR. So the question is: which tool is more
>  >
>  >  preferred/better JavaCC or ANTLR?
>  >
>  >
>  >  2008/3/28, Tim Ellison <t.p.ellison@gmail.com>:
>  >
>  >
>  > >
>  >  > Alexei Fedotov wrote:
>  >  > > Hello Aleksey,
>  >  > > That's great that you appeared on the list. That is nice to chat on
>  >  > > GTalk, but the list is preferred. People tend to think thoroughly
>  >  > > before sending their letters, so the communication become more
>  >  > > thoughtful and transparent. Please, don't hesitate to ask questions
on
>  >  > > the list: UK guys provide us an object lesson in English courtesy
>  >  > > here.
>  >  >
>  >  >
>  >  > LOL, yeah, not like those brash American-types ;-)
>  >  >
>  >  >
>  >  > > I'm happy that you are ok with RTF editor task. From mentor's FAQ it
>  >  > > reads that getting two dependent projects accepted is harder than
>  >  > > different projects.
>  >  >
>  >  >
>  >  > I think we just need the grammar, look at [1] for the CSS grammar.
>  >  >
>  >  > We already looked at one [2] contribution for RTF but the license does
>  >  > not allow us to incorporate it into Harmony.  We need an equivalent to
>  >  > that (but don't derive it from this version).
>  >  >
>  >  > [1]
>  >  >
>  >  > http://svn.apache.org/viewvc/harmony/enhanced/classlib/trunk/modules/swing/src/main/java/common/org/apache/harmony/x/swing/text/html/cssparser/CSSGrammar.jj?view=markup
>  >  > [2] http://issues.apache.org/jira/browse/HARMONY-3898
>  >  >
>  >  >
>  >  > Regards,
>  >  >
>  >  > Tim
>  >  >
>  >
>  >
>  >
>  >  --
>  >  Thanks,
>  >  Aleksey
>  >
>
>
>
>  --
>  With best regards,
>  Alexei
>

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