parser Calculator:
 option: "context-insensitive-scanner"
 token END: "$"
 token NUM: "[0-9]+"
 rule goal: expr END -> << expr>>
 rule expr: factor expr_tail<<factor>> -> << expr_tail>>
 rule expr_tail<<v>>: -> << v>>
 &#124; "+" factor expr_tail<<v+factor>> -> << expr_tail>>
 &#124; "-" factor expr_tail<<v-factor>> -> << expr_tail>>
 rule factor: term factor_tail<<term>> -> << factor_tail>>
 rule factor_tail<<v>>: -> << v>>
 &#124; "*" term factor_tail<<v*term>> -> << factor_tail>>
 &#124; "/" term factor_tail<<v/term>> -> << factor_tail>>
 rule term: NUM -> << atoi(NUM)>>
 &#124; "(" expr ")" -> << expr>>
</div><div class="naked_ctrl">
<form action="/index.cgi/contrast" method="get" name="gate">
<p><a href="http://altstyle.alfasado.net">AltStyle</a> によって変換されたページ <a href="http://theory.stanford.edu/~amitp/yapps/expr.g">(-&gt;オリジナル)</a>
/ <label>アドレス: <input type="text" name="naked_post_url" value="http://theory.stanford.edu/~amitp/yapps/expr.g" size="22" /></label> <label>モード: <select name="naked_post_mode">
<option value="default">デフォルト</option>
<option value="speech">音声ブラウザ</option>
<option value="ruby">ルビ付き</option>
<option value="contrast" selected="selected">配色反転</option>
<option value="larger-text">文字拡大</option>
<option value="mobile">モバイル</option>
</select>
<input type="submit" value="表示" />
</p>
</form>
</div>