[antlr-interest] Out of memory error

[Mark Bednarczyk]

I've experimented with this a lot.  And yes I have tried using the ? to make
the whole thing optional, but still run out of memory. 

tableConstants
	:	tableConstant (',' tableConstant)* ';'
		->	^(TABLE_CONST tableConstant)*
	|	';'!
	;


tableDeclaration
	:	modifiers 'table' id typeParameters? tableBody  
		-> ^(	TABLE_DEF id 
				modifiers 
				typeParameters?
				tableBody)
	;

variableDeclaratorRest
	:	('[' ']')+ ('=' variableInitializer)?
	|	'=' variableInitializer
	|	tableBody
	|
	;

As you can see tableConstants can take an optional single ';', so that is
the requirement right now for empty tables. It would be wonderful if I could
figure out how to make tableConstants optional so an empty table with no
constants would not require a single ';' to separate from the blockStatement
list. Tables in NPL are almost like enums in java except you are allowed
blockStatements inside the body of a table. 


Table body and blockStatement do not allow another table to be created
inside, so there shouldn't be any left recursion on rules, as far as I can
tell.

> 	-> {$tcs==null} ^(BLOCK_STATEMENT $bs*}
> 	-> 	          ^(SLIST $tcs)

Is using multiple '->' rewrites allowed? I haven't tried that yet.

Cheers,
mark...

> -----Original Message-----
> From: antlr-interest-bounces at antlr.org 
> [mailto:antlr-interest-bounces at antlr.org] On Behalf Of Jim Idle
> Sent: Wednesday, March 14, 2007 7:51 PM
> To: ANTLR Interest
> Subject: Re: [antlr-interest] Out of memory error
> 
> You could probably reduce the memory requirements by 
> expressing this slitghtly differently (needs 
> experimentation), though you can increase the heap space on 
> the jvm when you run ANTLR of course. I wonder if this will help you:
> 
> tableBody
> 	: '{' (tcs=tableConstants)? (bs+=blockStatement)* '}' 
> 
> ;
> 
> Then if you really do wish to write only the tableConstants 
> and ignore the blockStatements you can set a flag or check 
> for null in a conditional rewrite:
> 
> tableBody
> 	: '{' (tcs=tableConstants)? (bs+=blockStatement)* '}' 
> 
> 	-> {$tcs==null} ^(BLOCK_STATEMENT $bs*}
> 	-> 	          ^(SLIST $tcs)
> ;
> 
> -----Original Message-----
> From: antlr-interest-bounces at antlr.org
> [mailto:antlr-interest-bounces at antlr.org] On Behalf Of Mark Bednarczyk
> Sent: Wednesday, March 14, 2007 3:33 PM
> 
> 
> Here is the rule that triggers this error. If I comment out 
> the second alternative, I don't run out of memory:
> 
> tableBody
> 	:	('{' tableConstant)
> 		=> ('{' tableConstants blockStatement* '}')
> 		-> ^(SLIST tableConstants+)
> 		
> 	|	'{' blockStatement* '}'
> 	;
> 
> Cheers,
> mark...
> 
> 
>