anchor.diff:  
       // Next we have a series of zero or more import statements with
       // intermingled javadoc comments
  -    ( /* (invariantConditions)* */ importDefinition )*
  +    ( /* (invariantCondition)* */ importDefinition )*
       {
         clearInvariants();
       }
   
       // Wrapping things up with any number of class or interface definitions
       // with their corresponding invariants
  -     ( (invariantConditions)* typeDefinition )*
  +     ( (invariantCondition)* typeDefinition )*
   
       EOF
     ;
   
  -invariantConditions
  +invariantCondition
     : JAVADOC_OPEN ( iv:INVARIANT_CONDITION { addInvariant(iv); } | PRE_CONDITION | POST_CONDITION | ASSERT_CONDITION )* JAVADOC_CLOSE
     ;
   
  
positive.code: 	// empty statement
      |	SEMI
        
        //assertion
      |   assertCondition
  	)
      ;
  
  
  
negative.code:       lc:LCURLY
        // include the (possibly-empty) list of statements
        (statement)*
        rc:RCURLY
      )
      {
  