bench.rb

$:.unshift(File.expand_path('../lib', __FILE__))

require 'oga'
require 'benchmark/ips'
require 'nokogiri'

query    = 'foo/bar[baz]'
ast      = Oga::XPath::Parser.new(query).parse
compiler = Oga::XPath::Compiler.new
block    = compiler.compile(ast)

document = Oga.parse_xml <<-EOF
<foo a="b">
  <bar>
    <baz>This is the baz node</baz>
  </bar>
</foo>
EOF

noko_doc = Nokogiri::XML(document.to_xml)

Benchmark.ips do |bench|
  bench.report 'evaluator' do
    document.xpath(query)
  end

  bench.report 'compiler' do
    block.call(document)
  end

  bench.report 'nokogiri' do
    noko_doc.xpath(query)
  end

  bench.compare!
end

output.txt

end
Calculating -------------------------------------
           evaluator     2.613k i/100ms
            compiler    18.386k i/100ms
            nokogiri     3.561k i/100ms
-------------------------------------------------
           evaluator     27.535k (± 6.2%) i/s -    138.489k
            compiler    217.725k (±18.2%) i/s -      1.048M
            nokogiri     39.600k (± 2.8%) i/s -    199.416k

Comparison:
            compiler:   217725.3 i/s
            nokogiri:    39600.0 i/s - 5.50x slower
           evaluator:    27534.8 i/s - 7.91x slower