ruby-boost-regex

Wraps the Boost.Regex library to provide Boost regexes. Why? Why not! (Plus, it's worth seeing if it's faster.)

I'm trying to match the API to be at least completely compatible with normal Regexps, and then add Boost features. So far...

Features

Matches set global special variables like $`, $1-$9, $&, and so on
Supports =~ operator, === operator (for case...when)
Supports #match method as in normal Regexps, returning the same type of object (MatchData).
Spiffy monkey patch (see below)

Cool monkey patch

So monkey patching is bad, right? Right. And rubyists monkey patch all the time, which makes us bad people. Well, this module adds a new, alternate regex, but Ruby has a syntax for regexes already:

reg = /\d{3}/

This is nice because we don't have to escape the backslashes, plus it looks really nice with syntax highlighting. With these boost regexes, you'll either have to do

reg = Boost::Regexp.new("\\d{3}")
# or
reg = Boost::Regexp.new(/\d{3}/)

Why do all that typing? We have a literal regex syntax! But it creates normal regexes. So, we have a compromise:

Boost::Regexp.enable_monkey_patch! # only have to do this once
reg = /\d{3}/.boost!
reg.class # ==> Boost::Regexp

Cool, eh?

Of course, Boost gives us lots of crazy flags:

reg = /abc(def)/.boost!(Boost::Regexp::NO_SUBS & Boost::Regexp::IGNORECASE)
reg =~ "zzzABCDEF" # ==> 3
puts $1  # ==> nil

Benchmarks

I adapted the ruby-benchmark-suite's bm_regex_dna benchmark, which is used in the Computer Language Shootout. However, it uses str.scan(), which will fail if confronted with a non-standard Regexp. So I had to write my own, which is less optimized. The benchmark code is free to be scrutinized! It uses the standard benchmark module because lifting the spiffy one from ruby-benchmark-suite proved to be too much of a hassle for now.

Anyway, here's some results:

DNA-Matching (Computer Language Shootout)
=========================================
Rehearsal ------------------------------------------------
Normal regex  17.240000   0.050000  17.290000 ( 17.353051)
Oniguruma     16.300000   0.030000  16.330000 ( 16.384928)
Boost regex   11.400000   0.040000  11.440000 ( 11.489252)
-------------------------------------- total: 45.060000sec

                   user     system      total        real
Normal regex  17.190000   0.030000  17.220000 ( 17.273140)
Oniguruma     16.220000   0.040000  16.260000 ( 16.325460)
Boost regex   11.330000   0.030000  11.360000 ( 11.402222)

Failing to match a phone number in a big string of text
=======================================================
Rehearsal ------------------------------------------------
Normal regex   0.070000   0.000000   0.070000 (  0.072128)
Oniguruma      0.040000   0.000000   0.040000 (  0.043422)
Boost regex    0.040000   0.000000   0.040000 (  0.034708)
--------------------------------------- total: 0.150000sec

                   user     system      total        real
Normal regex   0.070000   0.000000   0.070000 (  0.071984)
Oniguruma      0.040000   0.000000   0.040000 (  0.044686)
Boost regex    0.030000   0.000000   0.030000 (  0.036421)

Usage

Install the gem, use as follows:

require 'ruby-boost-regex'

r = Boost::Regexp.new("(\\d{3})-(\\d{3})-(\\d{4})")
r =~ "555-123-4567"
p $1 # ==> "555"
matches = r.match("123-456-7890")
p matches[2] # ==> "456"

Boost::Regex.enable_monkey_patch!

r = /hello|world/i.boost!
r =~ "i'm Mike. Hello!" #==> 10

Installation

gem install ruby-boost-regex

Note on Patches/Pull Requests

Fork the project.
Make your feature addition or bug fix.
Add tests for it. This is important so I don't break it in a future version unintentionally.
Commit, do not mess with rakefile, version, or history. (if you want to have your own version, that is fine but bump version in a commit by itself I can ignore when I pull)
Send me a pull request. Bonus points for topic branches.