anchor.diff:      ;
   
   operationProcedureDecl
  -    :   OPERATION
  -        name=IDENTIFIER operationParameterList SEMICOLON
  -        (affectsClause)?
  -        (requiresClause)?
  -        (ensuresClause)?
  +    :   operationDecl
           PROCEDURE
           (facilityDecl)*
           (variableDecl)*
  
positive.code:     ;
  
  performanceOperationDecl
      :   OPERATION name=IDENTIFIER operationParameterList (COLON programNamedType)? SEMICOLON
          (affectsClause)?
          (requiresClause)?
          (ensuresClause)?
          (durationClause)?
          (manipulationDispClause)?
      ;
  
negative.code:     ;
  
  recursiveOperationProcedureDecl
      :   operationDecl
          RECURSIVE PROCEDURE
          decreasingClause
          (facilityDecl)*
  