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Serializing & case-insensitive languages (java.lang.RuntimeException: Could not serialize EObjec [message #1730502]

Tue, 26 April 2016 12:02

Gerd Wütherich

Messages: 12
Registered: July 2009

Junior Member

Hi,

currently I'm developing a xtext based cypher (neo4j) editor (xtext version 2.9.2). Fortunately I was able to solve nearly all issues I run into (google is my friend), but now I have to deal with an issue where I'm a bit lost...

The problem is that formatting several cypher queries throws exceptions like the following one (I use formatter2):

java.lang.RuntimeException: Could not serialize EObject via backtracking.
	Constraint: Expression1_Expression3_ExpressionNodeLabelsAndPropertyLookup_BoolConstant returns BoolConstant: ((value='TRUE' | value='FALSE') nodeLabelList+=NodeLabel* expression3Parts+=Expression3Part*);
	Values: value(1)
	Semantic Object: Cypher.statement->SingleQuery.clauses[0]->Match.pattern->Pattern.patterns[0]->PatternElement.nodepattern->NodePattern.properties->MapLiteral.entries[0]->MapLiteralEntry.value->BoolConstant
	URI: __synthetic0.cypher
	Context: Expression returns BoolConstant
		at org.eclipse.xtext.serializer.diagnostic.ISerializationDiagnostic$ExceptionThrowingAcceptor.accept(ISerializationDiagnostic.java:131)
		at org.eclipse.xtext.serializer.sequencer.BacktrackingSemanticSequencer.createSequence(BacktrackingSemanticSequencer.java:480)
		at de.gerdwuetherich.opencypher.serializer.OpenCypherSemanticSequencer.sequence_Expression1_Expression3_ExpressionNodeLabelsAndPropertyLookup(OpenCypherSemanticSequencer.java:1699)
		at de.gerdwuetherich.opencypher.serializer.OpenCypherSemanticSequencer.sequence(OpenCypherSemanticSequencer.java:281)

After some investigation I found out that it might has to do with the "case-insensitiveness". As keywords in cypher are case-insensitive, I set the parserGenerator options to 'ignoreCase = true' (which works perfectly fine).

However, if i parse and format a cypher query like

MATCH (a{abstract=TRUE} RETURN a;

(BoolConstant is 'TRUE'), everything works fine.

When I change the query to

MATCH (a{abstract=true} RETURN a;

(BoolConstant is 'true'), the exception above occurs.

Do I miss something? Do I have to specify the case-insensitive property for other generators as well? Currently I have no idea how to get rid of the exception...

kind regards
Gerd

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Re: Serializing & case-insensitive languages (java.lang.RuntimeException: Could not serialize EO [message #1730507 is a reply to message #1730502]

Tue, 26 April 2016 12:39

Christian Dietrich

Messages: 14665
Registered: July 2009

Senior Member

can you please file a bug for that.

you may fix org.eclipse.xtext.serializer.tokens.KeywordSerializer.isValid(EObject, Keyword, Object, Acceptor) yourself as workaround

Twitter : @chrdietrich
Blog : https://www.dietrich-it.de

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