gistfile1.rb

require "benchmark"

LITERALS = {
  nil => nil, 'nil' => nil, 'null' => nil, '' => nil,
  'true'  => true,
  'false' => false,
  'blank' => :blank?,
  'empty' => :empty?
}

def via_literal(key)
  LITERALS[key] if LITERALS.key?(key)
end

def via_case(key)
  case key
  when nil, 'nil', 'null', ''
    nil
  when 'true'
    true
  when 'false'
    false
  when 'blank'
    :blank?
  when 'empty'
    :empty?
  end
end

TESTS = 1_000_000
Benchmark.bmbm do |results|
  results.report('via_case(nil)') do
    TESTS.times { via_case(nil) }
  end
  
  results.report('via_literal(nil)') do
    TESTS.times { via_literal(nil) }
  end
  
  results.report('via_case("null")') do
    TESTS.times { via_case("null") }
  end
  
  results.report('via_literal("null")') do
    TESTS.times { via_literal("null") }
  end
  
  results.report('via_case("nomatch")') do
    TESTS.times { via_case("nomatch") }
  end
  
  results.report('via_literal("nomatch")') do
    TESTS.times { via_literal("nomatch") }
  end
end

Ruby 1.8.7

Rehearsal ----------------------------------------------------------
via_case(nil)            0.260000   0.000000   0.260000 (  0.296114)
via_literal(nil)         0.530000   0.000000   0.530000 (  0.552677)
via_case("null")         0.750000   0.000000   0.750000 (  0.761376)
via_literal("null")      0.570000   0.000000   0.570000 (  0.646138)
via_case("nomatch")      1.610000   0.000000   1.610000 (  1.669481)
via_literal("nomatch")   0.390000   0.010000   0.400000 (  0.430214)
------------------------------------------------- total: 4.120000sec

                             user     system      total        real
via_case(nil)            0.260000   0.000000   0.260000 (  0.263596)
via_literal(nil)         0.520000   0.000000   0.520000 (  0.530466)
via_case("null")         0.750000   0.000000   0.750000 (  0.772132)
via_literal("null")      0.560000   0.000000   0.560000 (  0.582794)
via_case("nomatch")      1.610000   0.000000   1.610000 (  1.803847)
via_literal("nomatch")   0.390000   0.000000   0.390000 (  0.395079)

Ruby 1.9.2

Rehearsal ----------------------------------------------------------
via_case(nil)            0.140000   0.000000   0.140000 (  0.146629)
via_literal(nil)         0.210000   0.000000   0.210000 (  0.210843)
via_case("null")         0.530000   0.000000   0.530000 (  0.561717)
via_literal("null")      0.350000   0.000000   0.350000 (  0.372644)
via_case("nomatch")      1.120000   0.010000   1.130000 (  1.135756)
via_literal("nomatch")   0.260000   0.000000   0.260000 (  0.271421)
------------------------------------------------- total: 2.620000sec

                             user     system      total        real
via_case(nil)            0.140000   0.000000   0.140000 (  0.174764)
via_literal(nil)         0.200000   0.000000   0.200000 (  0.280553)
via_case("null")         0.530000   0.000000   0.530000 (  0.570970)
via_literal("null")      0.360000   0.000000   0.360000 (  0.364196)
via_case("nomatch")      1.110000   0.000000   1.110000 (  1.165235)
via_literal("nomatch")   0.250000   0.000000   0.250000 (  0.293636)