code: function statementExpr(lastClause) {
        
        return function(ascent) {
     
           // kick off the evaluation by passing through to the last clause
           var exprMatch = lastClause(ascent);
                                                       
           return exprMatch === true ? head(ascent) : exprMatch;
        };
     }
docs: Generate a statement wrapper to sit around the outermost
  clause evaluator.
  
  Handles the case where the capturing is implicit because the JSONPath
  did not contain a '$' by returning the last node.