[antlr-interest] Cannot understand why parser accepts input...

[Bern.McCarty at bentley.com]

Yes that is a big help.  Thanks. At least now I see a
NoViableAltException in the interpreter output "diagram".  However,
there is still no indication of anything being amiss at all in the
console window.  Shouldn't the console window have something to say
about an exception that has caused parsing to fail?

 

-Bern

 

From: antlr-interest-bounces at antlr.org
[mailto:antlr-interest-bounces at antlr.org] On Behalf Of G R
Sent: Friday, December 07, 2007 7:26 AM
To: antlr at mirality.co.nz; antlr-interest at antlr.org
Subject: Re: [antlr-interest] Cannot understand why parser accepts
input...

 

Try using this lexer rule at the end of your grammar :

OtherChar :.;

This will define every character, and if you don't mention in your
grammar that you want a "OtherChar", then, an exception will be raised. 
Hope, this helps you.

G.R.

2007/12/7, Bern.McCarty at bentley.com <Bern.McCarty at bentley.com >:

...but when I enter a clearly invalid input into the interpreter such as
simply "3" or "B=3C the console contains no errors or warnings at all.

How could a mode that allows incorrect input without even issuing a
complaint/warning possibly be helpful? Is there a way to turn it off? 

Thanks,
-Bern



-----Original Message-----
From: antlr-interest-bounces at antlr.org
[mailto: antlr-interest-bounces at antlr.org
<mailto:antlr-interest-bounces at antlr.org> ] On Behalf Of Gavin Lambert
Sent: Friday, December 07, 2007 3:23 AM
To: Bern McCarty; antlr-interest at antlr.org
Subject: Re: [antlr-interest] Cannot understand why parser accepts 
input...

At 17:45 7/12/2007, Bern.McCarty at bentley.com wrote:

>Why does the below grammer successfully parse the input " B ==3C"
>When there are no numerals allowed anywhere in the grammer? 

It's an automatic error-recovery thing.  When ANTLRv3 encounters a
character it can't figure out, it prints an error to the console
(by default), drops the character, and then tries again.

 

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