Rubyでstrscanを使ってiniをパースする

実装

require "strscan"

def parse_ini src
  section = { "" => {} }
  current = section[""]
  s = StringScanner.new(src)

  while !s.eos?
    case
    when s.scan(/\s+/)
      # nothing
    when s.scan(/\[(.+?)\]/)
      section[s[1]] = current = {}
    when s.scan(/(\w+)\s*=\s*(["'])?([^\n]+)\2/)
      current[s[1]] = s[3]
    when s.scan(/(\w+)\s*=\s*(\d+\.\d+)/)
      current[s[1]] = s[2].to_f
    when s.scan(/(\w+)\s*=\s*([\d]+)/)
      current[s[1]] = s[2].to_i
    else
      raise "Parse Error. rest=#{ s.rest }"
    end
  end

  return section
end

if $0 == __FILE__
  require "pp"
  pp parse_ini(DATA.read)
end

__END__
piyo = "piyopiyo"

[foo]
name  = "hoge"
age   = 20
point = 10.7

[bar]
hoge = 'hogehoge'

実行結果

% ruby /tmp/aaa.rb
{""=>{"piyo"=>"piyopiyo"},
 "foo"=>{"name"=>"hoge", "age"=>20, "point"=>10.7},
 "bar"=>{"hoge"=>"hogehoge"}}

感想

Rubyでテキストをパースする時はstrscanが本当に便利!
もう正規表現には戻れない。