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The generated Sequencer of some Grammars gets too big in its init method. Maybe its pattern should be change (e.g. factoring out the or-ed conditions to own methods see - https://www.eclipse.org/forums/index.php/t/457587/ - https://www.eclipse.org/forums/index.php/m/1564072/
Created attachment 250335 [details] The sequencer.java class Please look into the init(IGrammarAccess) method.
Hi christian Thanks for filing a bug. I am using Windows 7 and eclipse version: Eclipse DSL Tools Version: Kepler Service Release 2 Build id: 20140224-0627 I have tried using a solution from the bug : https://bugs.eclipse.org/bugs/show_bug.cgi?id=349992 where it says to modify the fieldPerClass in the Options block. But still could not make it work. Thanks for help in advance. Regards Puneet
Thank you Puneet, but I'll need the grammar to do some useful analysis. Could you attach it to this bug? If you can't make the grammar public, would it be possible to send it to me via email? I can assure that I will not pass it to anybody else.
The options discussed in bug 349992 are for the parser and do not affect the serializer.
If the generated init() method gets too big, this means that for the serializer there are many syntactic ambiguities in your grammar. Example: Rule: "foo"? ("bar" | "baz") buz="buz"; For the serializer, there are two syntactic ambiguities here: - It doesn't know whether to write out "foo" - It doesn't know whether to write out "bar" or "baz" - "buz" is *not* a syntactic ambiguity, because due to the assignment buz= it's stored in the model. In your MyDslSyntacticSequencer, you'll find many emit_*() methods. Each method handles one syntactic ambiguity and the JavaDoc comment in front of the method contains the grammar snippet that is actually ambiguous for the serializer. To work around the too-big init() method, you can modify your grammar to be less ambiguous to the serializer, for example by introducing more assignments.
Don't confuse this bug with bug 457579. That bug appeared for a different reason.
Hi Moritz Thanks for your comments. Firstly, I will like to also point that I have quite a few unordered groups in my grammar. Secondly, Yes I see that the bug 349992 is for antlr generation problem. Thirdly, I am trying to understand the example and try to implement. Fourthly, I have sent you the grammar. Your co-operation will be highly solicited. Regards Puneet
ahh i missed 457579
Hi Moritz I understood the example and the concern in your comment. I also checked by modifying my grammar and reducing the emit_*() methods. In fact, I can avoid almost all of them by bringing in concrete assignments but I cannot do that. The reason being I am generating Xtext from EMF ecore model and not vice-versa. Therefore I cannot create utility EClasses in my ecore just to compensate the ambiguities that gets created in the serializer. Hope you understand what I mean.! Regards Puneet
Hi Moritz, I would really like to thank you, because your motivation to clean up the grammar worked out very very well. I cleaned up the grammar as opposed to what I sent you yesterday. The init() method has shrunk to a size of only 10 lines from 250 lines!! In the process, I also reduced the number of emit_*() methods. I guess these simple tricks and motivations should be provided in the documentation itself, so that user benefits. Anyways, the problem for the init() method exceeding 640K size still exists and hope you people find a way out. Thanks & Regards Puneet
The fix pushed to https://git.eclipse.org/r/#/c/41016/ reduces the size of Puneet's generated SyntacticSequencer from 2632 to 397 LOC. Java compiles the init() method just fine. The patch needs more cleanup and testing, though.
I'm interrupting my work on this bug in favor of other, faster-to-fix, bugs. The current state of work can be found here: https://git.eclipse.org/r/#/c/41016/
