Re: GDB/MI Output Syntax

[Bob Rossi <bob at brasko dot net>]

On Tue, Aug 24, 2004 at 02:58:01PM -0400, Andrew Cagney wrote:
> >Bob Rossi <bob@brasko.net> wrote:
> >
> >  ~"GNU gdb 6.1-debian\n"
> >  ~"Copyright 2004 Free Software Foundation, Inc.\n"
> >  ~"GDB is free software, covered by the GNU General Public License, and 
> >  you are\n"
> >  ~"welcome to change it and/or distribute copies of it under certain 
> >  conditions.\n"
> >  ~"Type \"show copying\" to see the conditions.\n"
> >  ~"There is absolutely no warranty for GDB.  Type \"show warranty\" for 
> >  details.\n"
> >  ~"This GDB was configured as \"i386-linux\"."
> >  ~"\n"
> >  (gdb) 
> >
> >This looks almost okay to me, it's just got a few differences with
> >newline characters versus the grammar
> >
> >  output -> (out-of-band-record)* [result-record] "gdb" NL
> >  (out-of-band-record)* -> stream_record stream_record stream_record 
> >  stream_record stream_record stream_record stream_record stream_record
> >  stream_record -> console_stream_output
> >  console_stream_output -> "~" C_STRING
> >  [result-record] ->
> >
> >It is eight stream-records in a row, where each stream-record is a
> >console-stream-output.  The gotcha is that the grammar as written does
> >not allow for a NL after a console-stream-output or a stream-record.
> 
> That's clearly a bug in the doco.  Any half decent compiler construction 
> course will use a new grammer each year (while stopping cheats, also 
> means that the students get to flush out a few bugs :-).

OK, so we can add that to the doco? I'll submit a patch.

> -> should all the [missing] @var{nl} be moved to @var{output}, that way 
> the're all in the one place.
> 
> Rossi writes:
> >Yes, this could work. However, was the original grammer meant to be
> >LALR(2)?
> 
> rewritable into something needing only one level of look-ahead, which I 
> see is being done.

Andrew, Michael has helped me figure out a more efficient way to reduce
the grammar. Now I have a LL(1) parser that has no conflicts, without
playing games in the lexer.

Also, a word of good news, so far I have sent several 'output' commands
of GDB through the parser, and it likes the syntax! This is a good thing
in my opinion, and so far, something to be thankful for :)

I would greatly appreciate it if we could validate GDB's output with the
library I am currently working on. I would love to know that everything
GDB outputs is sanitary. Anyways, the next step for me is to write a
syntax tree, representing the output. From there, I will be able to get
some work done on my front end.

Thanks,
Bob Rossi