mechanize：Mechanize::Form#set_fields

everyday Ruby

以下のような HTML で

<html>
<head>
<title>form test</title>
</head>
<body>

<form method="get" action="cgi/foo00.cgi" name="form1">
  <input type="hidden" name="hidden1" />

  <input type="text" name="text1" />
  <textarea name="textarea1" rows="4" cols="40">foo</textarea>

  <input type="text" name="text1" />
  <textarea name="textarea1" rows="4" cols="40">bar</textarea>
</form>

</body>
</html>
>> require 'mechanize'
=> true
>> agent = Mechanize.new
=> #<Mechanize:0xb74dc594 ...
>> page = agent.get('http://127.0.0.1:8080/test17_form.html')
=> #<Mechanize::Page
  ...
>> f = page.form('form1')
=> #<Mechanize::Form
  ...
>> f.fields_with(:name => "text1")[0].value
=> ""
>> f.fields_with(:name => "text1")[1].value
=> ""
>> f.fields_with(:name => "textarea1")[0].value
=> "foo"
>> f.fields_with(:name => "textarea1")[1].value
=> "bar"
>> f.set_fields(:text1 => "hoge")
=> {:text1=>"hoge"}
>> f.fields_with(:name => "text1")[0].value
=> "hoge"
>> f.fields_with(:name => "text1")[1].value
=> ""
>> f.set_fields(:text1 => { 0 => "HOGE" , 1 => "HOGEHOGE"})
=> {:text1=>{0=>"HOGE", 1=>"HOGEHOGE"}}
>> f.fields_with(:name => "text1")[0].value
=> "HOGE"
>> f.fields_with(:name => "text1")[1].value
=> "HOGEHOGE"

なんでインデックス番号なんかで指定するんだろう？と思ったけど、Array だと抜かして指定するのが面倒だからそうしたのかな？