From: daniel@...42.com Date: 2020-08-26T19:17:58+00:00 Subject: [ruby-core:99713] [Ruby master Bug#17030] Enumerable#grep{_v} should be optimized for Regexp Issue #17030 has been updated by Dan0042 (Daniel DeLorme). > Couldn't static analysis of the code determine in most cases if match data need be generated or not? scivola20 had a good idea, but this is even better. We can automatically get the best performance without having to manually optimize each case. But static analysis has other limits besides `const_get(:Regexp).last_match` ```ruby def foo(v) /x/ =~ 'x' # needs_last_match? depends on whether 'v' is regexp case method when v $1 end end ``` So a simpler approach would be to check if the match operation's scope (in this case the method body) contains any of the regexp-related pseudo-globals. ---------------------------------------- Bug #17030: Enumerable#grep{_v} should be optimized for Regexp https://bugs.ruby-lang.org/issues/17030#change-87203 * Author: marcandre (Marc-Andre Lafortune) * Status: Open * Priority: Normal * Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN ---------------------------------------- Currently: ```ruby array.select { |e| e.match?(REGEXP) } # about 3x faster and 6x more memory efficient than array.grep(REGEXP) ``` This is because `grep` calls `Regexp#===` which creates useless `MatchData` -- https://bugs.ruby-lang.org/ Unsubscribe: