slow-J commented on code in PR #12462: URL: https://github.com/apache/lucene/pull/12462#discussion_r1290188698
########## lucene/core/src/java/org/apache/lucene/util/automaton/RegExp.java: ########## @@ -1067,22 +1071,44 @@ private boolean check(int flag) { } final RegExp parseUnionExp() throws IllegalArgumentException { - RegExp e = parseInterExp(); - if (match('|')) e = makeUnion(flags, e, parseUnionExp()); - return e; + return iterativeParseExp(this::parseInterExp, () -> match('|'), RegExp::makeUnion); } final RegExp parseInterExp() throws IllegalArgumentException { - RegExp e = parseConcatExp(); - if (check(INTERSECTION) && match('&')) e = makeIntersection(flags, e, parseInterExp()); - return e; + return iterativeParseExp( + this::parseConcatExp, () -> check(INTERSECTION) && match('&'), RegExp::makeIntersection); } final RegExp parseConcatExp() throws IllegalArgumentException { - RegExp e = parseRepeatExp(); - if (more() && !peek(")|") && (!check(INTERSECTION) || !peek("&"))) - e = makeConcatenation(flags, e, parseConcatExp()); - return e; + return iterativeParseExp( + this::parseRepeatExp, + () -> (more() && !peek(")|") && (!check(INTERSECTION) || !peek("&"))), + RegExp::makeConcatenation); + } + + /** + * Custom Functional Interface for a Supplying methods with signature of RegExp(int int1, RegExp + * exp1, RegExp exp2) + */ + @FunctionalInterface + private interface MakeRegexGroup { + RegExp get(int int1, RegExp exp1, RegExp exp2); + } + + final RegExp iterativeParseExp( + Supplier<RegExp> gather, BooleanSupplier stop, MakeRegexGroup reduce) + throws IllegalArgumentException { + Deque<RegExp> regExpStack = new ArrayDeque<>(); Review Comment: Thanks for the suggestion Patrick and Stefan. As long as we do the suggested `reduce.get(flags, res, e)` instead of `reduce.get(flags, e, res)` the result should be correct. Will rename `reduce` to highlight it's associativeness. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: issues-unsubscr...@lucene.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@lucene.apache.org For additional commands, e-mail: issues-h...@lucene.apache.org