Timeline for When is a regexp not a Regular Expression?
Current License: CC BY-SA 4.0
13 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| May 16, 2022 at 11:46 | comment | added | ratchet freak | @assembly_wizard yeah I was assuming that there is no overlap where A and B could be. More formally A(?=B)C is A concatenated with intersection of B and C. (with the same reasoning) | |
| May 14, 2022 at 23:36 | comment | added | assembly_wizard | Look-around aren't always a simple intersection: ^A*(?=AB)B matches nothing, while the intersection of ^A*AB and ^A*B matches AAB. Though I'm pretty sure they're still regular. | |
| Mar 1, 2019 at 11:06 | history | edited | ratchet freak | CC BY-SA 4.0 | deleted 1 character in body |
| Feb 16, 2015 at 18:10 | history | edited | ratchet freak | CC BY-SA 3.0 | deleted 33 characters in body |
| Feb 16, 2015 at 16:33 | history | edited | ratchet freak | CC BY-SA 3.0 | added 6 characters in body |
| Feb 16, 2015 at 16:08 | history | edited | ratchet freak | CC BY-SA 3.0 | added 8 characters in body |
| Feb 16, 2015 at 13:59 | history | edited | ratchet freak | CC BY-SA 3.0 | added 359 characters in body |
| Feb 16, 2015 at 13:42 | history | edited | ratchet freak | CC BY-SA 3.0 | added 298 characters in body |
| Feb 16, 2015 at 13:36 | history | migrated | from programmers.stackexchange.com (revisions) | ||
| Feb 14, 2015 at 0:19 | comment | added | Jörg W Mittag | @MSalters: If you want to get really technical, (a)\1 is not a regular expression, but recognizes a regular language. | |
| Feb 13, 2015 at 22:56 | vote | accept | peperunas | ||
| Feb 13, 2015 at 12:40 | comment | added | MSalters | Is this necessary and sufficient? It looks to me like (a)\1, while using a backref, is equivalent to aa and therefore trivially Regular. I'm also wondering if lookahead assertions can use to recognize non-Regular languages. | |
| Feb 13, 2015 at 11:29 | history | answered | ratchet freak | CC BY-SA 3.0 |