[antlr-interest] (newbie problem)out of memory problem

[Kay Roepke]

On Jul 13, 2007, at 2:52 AM, ali azimi wrote:

>   I have written the following grammar and rewrite rule. However,  
> when I try to generate code it produces some problems (like java  
> out of memory and I am sure the problem in my grammar comes from  
> this rule). Could you recommend a better way of writing it?

org.antlr.Tool is out of memory? If so, try to pass the -Xmx300m  
argument (substituting the appropriate of max memory) to the Java call.
However, I don't think the rule in question really is the problem, as  
the lookahead is fine for a simple test case I just made up.

It might however all depend on the rules you didn't include in your  
mail. There's no way to figure out the problem from just this rule.

>   blocksubstructuredefinition
>          :'substructure' qualifier? blocksubstructurename?  
> end'endsubstructure'qualifier? blocksubstructurename? end
>           (entityinsystem+ ->^('substructure' qualifier?  
> blocksubstructurename? end 'endsubstructure'qualifier?  
> blocksubstructurename? end  entityinsystem+ )
>               |channelconnection+ ->^('substructure' qualifier?  
> blocksubstructurename? end'endsubstructure'qualifier?  
> blocksubstructurename? end  channelconnection+ )
>               )
>               ;

Also, use whitespace and underscores or camelCase. The rule is really  
hard to read this way. You'll be thanking yourself sometime down the  
road...
And:
The rewrite rules don't look right to me, but this hasn't anything to  
do with you original question.
You haven't assigned labels to the qualifier,  blocksubstructurename,  
and end rules but reference them twice in the rule and in the rewrite.
This way, in the rewrite, you will end up with the first references  
twice because ANTLR calls reset() on the RewriteRuleSubtreeStreams.
That's probably not what you meant. Assign labels to the rule  
references and use the labels in the rewrites.

blocksubstructuredefinition
	:	'substructure'
			q1=qualifier? b1=blocksubstructurename? e1=end
		'endsubstructure'
			q2=qualifier? b2=blocksubstructurename? e2=end
		(	entityinsystem+		-> ^('substructure' $q1? $b1? $e1  
'endsubstructure' $q2? $b2? $e2 entityinsystem+ )
		|	channelconnection+	-> ^('substructure' $q1? $b1? $e1  
'endsubstructure' $q2? $b2? $e2 channelconnection+ )
		)
	;

HTH,
-k

-- 
Kay Röpke
http://classdump.org/