From: vivian.unger@... Date: 2019-08-17T18:30:17+00:00 Subject: [ruby-core:94402] [Ruby master Bug#16108] gsub gives wrong results with regex backreferencing and triple backslash Issue #16108 has been reported by VivianUnger (Vivian Unger). ---------------------------------------- Bug #16108: gsub gives wrong results with regex backreferencing and triple backslash https://bugs.ruby-lang.org/issues/16108 * Author: VivianUnger (Vivian Unger) * Status: Open * Priority: Normal * Assignee: * Target version: * ruby -v: ruby 2.6.3p62 (2019-04-16 revision 67580) [x64-mingw32] * Backport: 2.5: UNKNOWN, 2.6: UNKNOWN ---------------------------------------- I have written a script to convert LaTeX indexing files (.idx) to Macrex backup format (.mbk), so that I can import LaTeX-embedded indexes into the Macrex indexing program. A problem arises when I try to convert bolded text. LaTeX indicates bolded text with the tag \textbf{} while Macrex wraps it in backslashes: \\. In my test case, the input string is "\indexentry{\textbf{bold}|hyperpage}{2}", which I need to convert into "\indexentry{\bold\|hyperpage}{2}". For this I am using: record.gsub(/\\textbf\{([^\}]+)\}/, '\\\1\\') But instead of the expected output, I get: \indexentry{\1\|hyperpage}{2} ...as if I only had \\ rather than \\\. I have tried the same Regex in a search-and-replace in Notepad++ and it works as expected. It's only in Ruby that I get this unexpected result. The kludgey workaround I have found is to leave a space before the \\: record.gsub(/\\textbf\{([^\}]+)\}/, '\\ \1\\') ...giving the result: \indexentry{\ bold\|hyperpage}{2} But this won't do. Macrex complains and the extra space has to be edited out. Imagine if you have hundreds of lines with bold text in them! -- https://bugs.ruby-lang.org/ Unsubscribe: