Hi Wolfgang, This is not a mvel issue, that in this is case is correctly reporting the syntax error, but only a small bug in drools failing to catch and correctly menage the excpetion thrown by mvel in that particular case. I just pushed the fix, thank you for reporting this. Mario On Sun, Mar 11, 2012 at 7:26 PM, Wolfgang Laun <wolfgang.laun(a)gmail.com&gt;wrote: > This is not correct: > Foo( id == "\a" ) > and it is rightly flagged as a syntax error, but the ensuing stack dump is > uncalled for: > > Exception in thread "main" [Error: illegal escape sequence: a] > [Near : {... "\a" ....}] > ^ > [Line: 1, Column: 3] > at org.mvel2.util.ParseTools.handleEscapeSequence(ParseTools.java:889) > at org.mvel2.util.ParseTools.handleStringEscapes(ParseTools.java:1533) > at org.mvel2.compiler.AbstractParser.nextToken(AbstractParser.java:1105) > at > org.mvel2.compiler.ExpressionCompiler._compile(ExpressionCompiler.java:128) > at > org.mvel2.compiler.ExpressionCompiler.compile(ExpressionCompiler.java:62) > at org.mvel2.MVEL.analysisCompile(MVEL.java:670) > at org.mvel2.MVEL.analysisCompile(MVEL.java:674) > at > org.drools.rule.builder.PatternBuilder.setInputs(PatternBuilder.java:942) > at > org.drools.rule.builder.PatternBuilder.buildRelationalExpression(PatternBuilder.java:638) > at org.drools.rule.builder.PatternBuilder.build(PatternBuilder.java:588) > at > org.drools.rule.builder.PatternBuilder.processConstraintsAndBinds(PatternBuilder.java:449) > at org.drools.rule.builder.PatternBuilder.build(PatternBuilder.java:296) > at org.drools.rule.builder.PatternBuilder.build(PatternBuilder.java:118) > at > org.drools.rule.builder.GroupElementBuilder.build(GroupElementBuilder.java:65) > at org.drools.rule.builder.RuleBuilder.build(RuleBuilder.java:80) > at org.drools.compiler.PackageBuilder.addRule(PackageBuilder.java:2503) > at org.drools.compiler.PackageBuilder.addPackage(PackageBuilder.java:847) > at > org.drools.compiler.PackageBuilder.addPackageFromDrl(PackageBuilder.java:443) > at > org.drools.compiler.PackageBuilder.addKnowledgeResource(PackageBuilder.java:626) > at > org.drools.builder.impl.KnowledgeBuilderImpl.add(KnowledgeBuilderImpl.java:41) > at foobar.Main.setup(Main.java:68) > at foobar.Main.main(Main.java:124) > > -W > > > _______________________________________________ > rules-dev mailing list > rules-dev(a)lists.jboss.org > https://lists.jboss.org/mailman/listinfo/rules-dev > >