jruby_to_r_regex_last_match.rb

def foo
  if("moo" =~ /(\w+)/)
    puts "  inside foo: #{$1.inspect} #{Regexp.last_match.inspect}"
  end
end

def replace
  "something".gsub(/(foo)/, "bar")
end

class String
  def replace_test
    self.gsub(/(foo)/, "bar")
  end
end

def bar
  if("hello" =~ /(\w+)/)
    puts "before foo: #{$1.inspect} #{Regexp.last_match.inspect}"
    foo
    puts "after foo: #{$1.inspect} #{Regexp.last_match.inspect}"
    5.to_r
    puts "after Integer#to_r: #{$1.inspect} #{Regexp.last_match.inspect}"
    0.25.to_r
    puts "after Float#to_r: #{$1.inspect} #{Regexp.last_match.inspect}"
    replace
    puts "after replace: #{$1.inspect} #{Regexp.last_match.inspect}"
    ".25".replace_test
    puts "after String#replace_test: #{$1.inspect} #{Regexp.last_match.inspect}"
    ".25".to_r
    puts "after String#to_r: #{$1.inspect} #{Regexp.last_match.inspect}"
  end
end

bar

# MRI ruby 1.9.3p545
# before foo: "hello" #<MatchData "hello" 1:"hello">
#   inside foo: "moo" #<MatchData "moo" 1:"moo">
# after foo: "hello" #<MatchData "hello" 1:"hello">
# after Integer#to_r: "hello" #<MatchData "hello" 1:"hello">
# after Float#to_r: "hello" #<MatchData "hello" 1:"hello">
# after replace: "hello" #<MatchData "hello" 1:"hello">
# after String#replace_test: "hello" #<MatchData "hello" 1:"hello">
# after String#to_r: "hello" #<MatchData "hello" 1:"hello">
#
# MRI ruby 2.1.1p76
# before foo: "hello" #<MatchData "hello" 1:"hello">
#   inside foo: "moo" #<MatchData "moo" 1:"moo">
# after foo: "hello" #<MatchData "hello" 1:"hello">
# after Integer#to_r: "hello" #<MatchData "hello" 1:"hello">
# after Float#to_r: "hello" #<MatchData "hello" 1:"hello">
# after replace: "hello" #<MatchData "hello" 1:"hello">
# after String#replace_test: "hello" #<MatchData "hello" 1:"hello">
# after String#to_r: "hello" #<MatchData "hello" 1:"hello">
#
# JRuby 1.7.11
# before foo: "hello" #<MatchData "hello" 1:"hello">
#   inside foo: "moo" #<MatchData "moo" 1:"moo">
# after foo: "hello" #<MatchData "hello" 1:"hello">
# after Integer#to_r: "hello" #<MatchData "hello" 1:"hello">
# after Float#to_r: "hello" #<MatchData "hello" 1:"hello">
# after replace: "hello" #<MatchData "hello" 1:"hello">
# after String#replace_test: "hello" #<MatchData "hello" 1:"hello">
# after String#to_r: nil nil