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Re: GDB/MI Output Syntax
- From: Bob Rossi <bob at brasko dot net>
- To: Andrew Cagney <cagney at gnu dot org>
- Cc: gdb at sources dot redhat dot com
- Date: Thu, 26 Aug 2004 17:25:17 -0400
- Subject: Re: GDB/MI Output Syntax
- References: <20040825154348.GA19533@white> <412E5221.8010601@gnu.org>
On Thu, Aug 26, 2004 at 05:12:01PM -0400, Andrew Cagney wrote:
> >Hi,
> >
> >Along with the newline changes, there are 2 other changes that I propose
> >to the grammar. They are,
> >
> >async-record ==> exec-async-output | status-async-output |
> >notify-async-output
> >exec-async-output ==> [ token ] "*" async-output
> >status-async-output ==> [ token ] "+" async-output
> >notify-async-output ==> [ token ] "=" async-output]
>
> FYI, these were done this way so that the complete structure and intent
> was clear (rather than worry about language issues). As you note a
> rewrite gives an ll(1) grammar; it also looses that clarity.
Yes, clarity is very important. Honestly, Michael helped me get the
original grammar to be ll(1). The only problem with the original grammar
that I have found so far is that it is missing a 'nl' on one line.
I only propose rearranging the gramar a little, written in the way
that it is in the doco. Also, I propose that the grammar Michael and I
are working also get posted, and say that it is a dirivative of the
original. Both ways of posting the data are helpful to front end
developers.
The only change to the original grammar I am interested in is to match
the names/rules to be similar to the grammar that Michael and I are
generated (loosing productions we have eliminated, adding productions
that we added, ... ). Either way, I think it would be helpful to say,
here is the grammar, and here is the bison input to the grammar.
In the end, it's up to you guys.
> >The second change is identical but refers to the rules of
> > stream-record ==> console-stream-output | target-stream-output |
> > log-stream-output
> > console-stream-output ==> "~" c-string
> > target-stream-output ==> "@" c-string
> > log-stream-output ==> "&" c-string
> >
> >to
> > stream-record => stream-record-kind c-string
> > stream-record-kind => "~" | "@" | "&"
> >
> >The reason it would be helpful to modify the grammar in this way is that
> >it leads to a more elegant form when trying to build an intermediate
> >representation. At the parse level of 'stream-record' or 'async-record'
> >you have all of the information necessary in order to populate a
> >structure with data. Otherwise, the information is a few levels down
> >stream.
>
> I don't follow.
This may not interest you at all. However, with the rules,
> > stream-record ==> console-stream-output | target-stream-output |
> > log-stream-output
> > console-stream-output ==> "~" c-string
> > target-stream-output ==> "@" c-string
> > log-stream-output ==> "&" c-string
when bison get's to stream-record, it doesn't have available to it the
c-string data. So, I can't do
stream_record: stream_record_class CSTRING {
$$ = malloc ( sizeof ( struct stream_record ) );
$$->stream_record = $1;
$$->cstring = strdup ( gdbmi_text );
};
With the rules,
> > stream-record => stream-record-kind c-string
> > stream-record-kind => "~" | "@" | "&"
I can do the above code, which is nice.
I understand there is other ways to do the same thing, however, this
seems elegant to me.
Thanks,
Bob Rossi