# Ruby Regexp implementation? **URL:** \ **Category:** ruby-talk\ **Created:** [12 March 2010 18:54 UTC](https://rubytalk.org/t/ruby-regexp-implementation/57750 "2010-03-12T18:54:09Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![Aldric\_Giacomoni2](https://avatars.discourse-cdn.com/v4/letter/a/91b2a8/32.png) [@Aldric\_Giacomoni2](https://rubytalk.org/u/Aldric_Giacomoni2)\ **Post date:** [12 March 2010 18:54 UTC](https://rubytalk.org/t/ruby-regexp-implementation/57750/1 "2010-03-12T18:54:09Z")
This probably doesn't belong in Ruby Core. I was reading this article: [http://swtch.com/~rsc/regexp/regexp1.html](http://swtch.com/~rsc/regexp/regexp1.html) [http://swtch.com/~rsc/regexp/regexp2.html](http://swtch.com/~rsc/regexp/regexp2.html) [http://swtch.com/~rsc/regexp/regexp3.html](http://swtch.com/~rsc/regexp/regexp3.html) And in the first few lines of the first page, it shows that the Regexp implementation for Perl is absolutely terrible, and it says that Ruby is "the same" or at least similar. Is Ruby 1.8 / 1.9 using the Thompson NFA matching? Will Ruby 2.0 use it? > **···** > > -- > Posted via [http://www.ruby-forum.com/](http://www.ruby-forum.com/). ---
**Author:** ![Chuck\_Remes](https://avatars.discourse-cdn.com/v4/letter/c/3be4f8/32.png) [@Chuck\_Remes](https://rubytalk.org/u/Chuck_Remes)\ **Post date:** [12 March 2010 21:04 UTC](https://rubytalk.org/t/ruby-regexp-implementation/57750/2 "2010-03-12T21:04:24Z")
I remember reading that article when it was first published. Ruby switched to a new regex library almost 2 years ago. Check out [http://rubyforge.org/projects/oniguruma](http://rubyforge.org/projects/oniguruma) for more information. It would be interesting to see those benchmarks run again with these new implementations. cr > **···** > > On Mar 12, 2010, at 12:54 PM, Aldric Giacomoni wrote: > > > This probably doesn't belong in Ruby Core. I was reading this article: > > [Regular Expression Matching Can Be Simple And Fast](http://swtch.com/~rsc/regexp/regexp1.html) > > [Regular Expression Matching: the Virtual Machine Approach](http://swtch.com/~rsc/regexp/regexp2.html) > > [Regular Expression Matching in the Wild](http://swtch.com/~rsc/regexp/regexp3.html) > > > > And in the first few lines of the first page, it shows that the Regexp > > implementation for Perl is absolutely terrible, and it says that Ruby is > > "the same" or at least similar. Is Ruby 1.8 / 1.9 using the Thompson NFA > > matching? Will Ruby 2.0 use it? ---
**Author:** ![Siep\_Korteling](https://avatars.discourse-cdn.com/v4/letter/s/41988e/32.png) [@Siep\_Korteling](https://rubytalk.org/u/Siep_Korteling)\ **Post date:** [12 March 2010 21:14 UTC](https://rubytalk.org/t/ruby-regexp-implementation/57750/3 "2010-03-12T21:14:29Z")
Aldric Giacomoni wrote: > This probably doesn't belong in Ruby Core. I was reading this article: > [Regular Expression Matching Can Be Simple And Fast](http://swtch.com/~rsc/regexp/regexp1.html) > [Regular Expression Matching: the Virtual Machine Approach](http://swtch.com/~rsc/regexp/regexp2.html) > [Regular Expression Matching in the Wild](http://swtch.com/~rsc/regexp/regexp3.html) > > And in the first few lines of the first page, it shows that the Regexp > implementation for Perl is absolutely terrible, and it says that Ruby is > "the same" or at least similar. Is Ruby 1.8 / 1.9 using the Thompson NFA > matching? Will Ruby 2.0 use it? def pathologicalize (str, n)   tmp = str[0]\*n   [str\*n + tmp, tmp] end puts RUBY\_VERSION 1.step(101, 10) do |n|   full\_str, part\_str = pathologicalize("a?", n)   start = Time.now   1000.times do     full\_str =~ /#{part\_str}/   end   duration = Time.now-start   puts "#{n}:\t#{duration}" end #output 1.9.1 1: 0.015625 11: 0.015625 21: 0.015625 31: 0.03125 41: 0.03125 51: 0.046875 61: 0.046875 71: 0.046875 81: 0.0625 91: 0.0625 101: 0.078125 Siep > **···** > > -- > Posted via [http://www.ruby-forum.com/\](http://www.ruby-forum.com/%5C). ---
**Author:** ![Yukihiro\_Matsumoto2](https://avatars.discourse-cdn.com/v4/letter/y/b9e5f3/32.png) [@Yukihiro\_Matsumoto2](https://rubytalk.org/u/Yukihiro_Matsumoto2)\ **Post date:** [12 March 2010 22:47 UTC](https://rubytalk.org/t/ruby-regexp-implementation/57750/4 "2010-03-12T22:47:21Z")
Hi, > **···** > > In message "Re: Ruby Regexp implementation?" on Sat, 13 Mar 2010 03:54:09 +0900, Aldric Giacomoni \ writes: > > > And in the first few lines of the first page, it shows that the Regexp > > implementation for Perl is absolutely terrible, and it says that Ruby is > > "the same" or at least similar. Is Ruby 1.8 / 1.9 using the Thompson NFA > > matching? Will Ruby 2.0 use it? > > No plan. We need more (human) resource. > >               matz.