[hibernate-dev] HQL Grammar for "ON" joins...

[Steve Ebersole]

On Thursday 20 September 2007 09:14:47 am James Carman wrote:
> What do you guys think about this...
>
> fromClause
>
> 	: FROM^ { weakKeywords(); } fromRange ( onJoin | pathJoin | COMMA! {
>
> weakKeywords(); } fromRange )*
> 	;
>
> onJoin
>
>     : ( ( ( LEFT | RIGHT ) (OUTER)? ) | FULL | INNER )? JOIN^
>
>       identifier asAlias ON^ logicalExpression
>     ;
>
> pathJoin
>
>     : ( ( ( LEFT | RIGHT ) (OUTER)? ) | FULL | INNER )? JOIN^ (FETCH)?
>
> 	  path (asAlias)? (propertyFetch)? (withClause)?
>     ;
>
> The "pathJoin" is basically what we currently support.  The "onJoin"
> is what we want to support.  Does it look correct to you?
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At a bare minimum this would not work because the identifier sub-rule result 
(recognized after JOIN) would need to be resolved before allowing the lexer 
to continue on to the resolution of the logicalExpression sub-rule.

But even more basic, I don't think "identifier" is the correct sub-rule here.  
It would catch imported entity name scenarios, but obviously fail on 
non-imported entity names (aka FQN).

Have you looked the grammars I started for the re-work of the query parser?  
It is obviously more work to go this route, but much more correct imo.

http://viewvc.jboss.org/cgi-bin/viewvc.cgi/hibernate/core/branches/HQL_ANTLR_2/g2/