private ExpressionFunction parseRankingExpression(String name, List<String> arguments, String expression) throws ParseException {
        if (expression.trim().isEmpty())
            throw new ParseException("Empty expression");

        try (Reader rankingExpressionReader = openRankingExpressionReader(name, expression.trim())) {
            return new ExpressionFunction(name, arguments, new RankingExpression(name, rankingExpressionReader));
        }
        catch (com.yahoo.searchlib.rankingexpression.parser.ParseException e) {
            ParseException exception = new ParseException("Invalid expression '" + expression.trim());
            throw (ParseException)exception.initCause(e);
        }
        catch (IOException e) {
            throw new RuntimeException("IOException parsing ranking expression '" + name + "'", e);
        }
    }
Returns all filter fields in this profile and any profile it inherits.
config-model/src/main/java/com/yahoo/schema/RankProfile.java