[ruby-core:99714] [Ruby master Bug#17030] Enumerable#grep{_v} should be optimized for Regexp
From:
marcandre-ruby-core@...
Date:
2020-08-26 19:31:50 UTC
List:
ruby-core #99714
Issue #17030 has been updated by marcandre (Marc-Andre Lafortune).
Dan0042 (Daniel DeLorme) wrote in #note-15:
> But static analysis has other limits
Good example but it is easily resolved: assume `v` isn't a Regexp and we may get a false positive, which is not a big issue. There will be other false positives: `str.gsub(regexp, &block)`. That's not a real issue, simply assume that `block` will want access to `Regexp.last_match`. I'm really only worried about false negatives... Any other example comes to mind?
----------------------------------------
Bug #17030: Enumerable#grep{_v} should be optimized for Regexp
https://bugs.ruby-lang.org/issues/17030#change-87204
* 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: <mailto:ruby-core-request@ruby-lang.org?subject=unsubscribe>
<http://lists.ruby-lang.org/cgi-bin/mailman/options/ruby-core>