[antlr-interest] Is ANTLR Hallucinating?

Thomas Brandon tbrandonau at gmail.com
Tue Jun 26 07:32:18 PDT 2007


On 6/27/07, Randall R Schulz <rschulz at sonic.net> wrote:
> On Tuesday 26 June 2007 07:03, Wincent Colaiuta wrote:
> > El 26/6/2007, a las 15:59, Randall R Schulz escribió:
> > >> Yeah, I'm using standalone ANTLRWorks as well. This screenshot
> > >> (<http://antlr.org/works/screenshots/ambiguouspath.jpg>) shows
> > >> what ambiguous path visualization looks like. Note the check boxes
> > >> for the alternatives; in order to see both paths both check boxes
> > >> must be checked.
> > >
> > > I've never seen anything like that, even when I get those warnings
> > > from
> > > the ANTLR tool.
> > >
> > > How do you get multiple productions at one time in the Syntax
> > > Diagram? I
> > > can't get that to happen—I never see the racetrack diagram for more
> > > than one production at a time.
> >
> > No specific action should be required on your part. If multiple rules
> > need to be shown in order to display the ambiguous paths then
> > ANTLRWorks should display them automatically whenever the rule with
> > the ambiguity (highlighted red in the list of rules) is selected.
>
> Too many interacting issues and options...
>
> So I have to turn off backtracking and then try to apply the grammar in
> the Interpreter before it does whatever it does to recompute the
> conflicts. (I just saw your message about using the Generate Code
> command instead of the Interpreter). Then I get non-terminal /
> production names in red and when I select one of them, I see the set of
> rules that participate in the ambiguity with the green and red conflict
> arcs.
>
You can also run Grammar->Check Grammar to display ambiguities.
> What does the bold, pulsating red arc mean?
I believe the first segment of the path is displayed like that.
>
>
> Is anything supposed to happend when I issue the Help command (from the
> Help menu)? 'Cause nothing happens on my system (not even a "not help
> available" alert).
I get a browser open at http://www.antlr.org/works/help/index.html
>
> Also, when the conflict diagram is displayed and the ANTLRworks window
> is active, it seems to consume all available CPU cycles.
I get higher CPU usage (about 11% compared to 5% normally) when
viewing a syntax diagram, but thats on windows (dualcore 3GHz).
>
>
> > Cheers,
> > Wincent
>
>
> Thanks for your help.
>
> Randall Schulz
>
Tom.


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