[antlr-interest] Error handling using parallel instances of a C-target parser

[Johannes Goller]

Thank you, Jim, for the quick reply.
I read through all the posts I could find related to
displayRecognitionError, but I still have one question:
Inside my new definition of displayRecongitionError, how do I access
the members of my parser defined
through @apifuncs?

displayRecongitionError has two arguments: the recognizer and the
token names. The recognizer appears
to contain a "super" pointer that leads to the ANTLR3_PARSER struct.
That also has a "super" member, but
I don't understand where it points to.
How can I get to the data structure, whose members are defined by @apifuncs?


Many thanks,
johannes.


Use antlr.markmail.org and look for displayRecognitionError. Remember that if
you have parallel threads, you will want the error collections to be thread
instances, not global members. Therefore you add them as context members
@apifuncs etc.

http://antlr.markmail.org/search/?q=apifuncs#

http://antlr.markmail.org/search/?q=displayRecognitionError+C

Jim

-----Original Message----- From: antl... at antlr.org
[mailto:antlr-interest- boun... at antlr.org] On Behalf Of Johannes
Goller Sent: Sunday, May 09, 2010 11:05 PM To: antl... at antlr.org
Subject: [antlr-interest] Error handling using parallel instances of a
C-target parser

Hello,

I am working with a C-target parser, and I have multiple instances of
the parser running in parallel.

Now I would like to stop the parser from printing error messages to
stderr. Instead, I would like each instance of the parser to collect
the error messages in a list of strings, so that the caller can access
the complete list of error messages after the parser finished and
decide what to do about them.

>From an example I found here: http://groups.google.com/group/il-antlr-
interest/browse_thread/thread/80ec25032e9af7a8?pli=1 I understand how
members of the parser instance can be defined using @parser::context
and @parser::apifuncs, and that works very well. So, let's say I
defined a member

error_list_t *error_list

which points to some kind of dynamic list structure, and assume there
is a global function

add_to_error_list(error_list_t *, const char* msg)

which can be used to add a new message to the list.

Now I wonder how can the error handling methods of ANTLR be modified
to add error messages to the list rather than printing them to stderr.

Looking at various sources on the internet, it seems there is a
function emitErrorMessage() which is called whenever an error occurs.
Taking that as a starting point, I have the following questions:

(1) Is that the right function to override? Or is there a better one?
(2) How exactly do I have to specifiy the override in the ANTLR
grammar? (3) How can I access the current instance of the parser from
inside the error handling function? Remember that error_list must be a
member of the parser, rather than a global object, because I have
several parsers operating in parallel.

Many thanks for any help.

johannes.

List: http://www.antlr.org/mailman/listinfo/antlr-interest
Unsubscribe: http://www.antlr.org/mailman/options/antlr-interest/your-
email-address