From: shortcutter@... Date: 2016-09-06T13:54:51+00:00 Subject: [ruby-core:77160] [Ruby trunk Bug#12728] Negative lookahead does not work for "+" even though works for "@" Issue #12728 has been reported by Robert Klemme. ---------------------------------------- Bug #12728: Negative lookahead does not work for "+" even though works for "@" https://bugs.ruby-lang.org/issues/12728 * Author: Robert Klemme * Status: Open * Priority: Normal * Assignee: * ruby -v: ruby 2.2.5p319 (2016-04-26 revision 54774) [x86_64-cygwin] * Backport: 2.1: UNKNOWN, 2.2: UNKNOWN, 2.3: UNKNOWN ---------------------------------------- I'll attach a test program that shows the effect. Basically, if I have a negative lookahead in the regex like (?!@) and "@" shows up in the proper location I get a mismatch (1. case). This is expected. If I exchange the "@" with a "\+" or "[+]" in the regex and a "+" in the input, a match occurs (case 2 and 3). This is the bug. If the "+" or "@" is removed from the string an expected match occurs (case 4 and 5). I was not able to boil this down to a smaller example yet. ---Files-------------------------------- rx-mini.rb (1.63 KB) -- https://bugs.ruby-lang.org/ Unsubscribe: