小编Dfr*_*Dfr的帖子

我想在Haskell中创建一个简单的url路由,并且无法绕过警告:

Warning: Pattern match(es) are overlapped
             In a case alternative: "/" -> ...
Ok, modules loaded: Main.

片段:

{-# LANGUAGE OverloadedStrings #-}
import Network.Wai
import Network.Wai.Handler.Warp (run)
import Network.Wai.Middleware.Debug (debug)
import Network.HTTP.Types (statusOK, status404)
import qualified Data.ByteString as B
import qualified Data.ByteString.Lazy as L
import Data.ByteString.Char8 (unpack)
import Data.ByteString.Lazy.Char8 (pack)
import qualified Data.Text.Lazy as T
import Control.Monad.IO.Class (liftIO, MonadIO)

application req = do
  case unpack $ rawPathInfo req of
    "/items" -> itemsJSON 
    "/" -> indexPage
    _ ->  return $ responseLBS …

美好的一天,我的问题是关于优化SQL查询.以下查询很慢:

SELECT id, name,
, (SELECT rank_time FROM stage_rank WHERE stage = stage.id ORDER BY rank_time DESC LIMIT 1)::date AS rank_time
, (SELECT host_c    FROM stage_rank WHERE stage = stage.id ORDER BY rank_time DESC LIMIT 1) AS host_c
, (SELECT index_pa  FROM stage_rank WHERE stage = stage.id ORDER BY rank_time DESC LIMIT 1) AS index_pa
, (SELECT links_pa  FROM stage_rank WHERE stage = stage.id ORDER BY rank_time DESC LIMIT 1) AS links_pa
, (SELECT index_pb  FROM stage_rank WHERE stage = …

当用户单击any时commandButton，则在托管bean中调用相应的操作。是否可以从@PostConstruct方法或事件侦听器方法中获取此动作名称？

这是一个小的perl片段:

my $n = 1;
my $re_str = '\d';
my $re_str_q = '\Q1\E';

printf "re_str   match: %s\n", ($n =~ /$re_str/);
printf "re_str_q match: %s\n", ($n =~ /$re_str_q/);
printf "direct match: %s\n", ($n =~ /\Q1\E/);

运行时产生以下输出:

re_str   match: 1
re_str_q match: 
direct match: 1

所以,我的问题是为什么第二个printf不匹配？

这是一个例子:

  <table>
    <tr>
    <td style="background: lightgreen; vertical-align: middle">
      <button type="button">b1</button>
    </td>
    <td style="background: yellow; vertical-align: middle">
      <button type="button">b2</button>
        <textarea cols="40" rows="2"></textarea>
    </td>
    </tr>
  </table>

这里是JSFiddle链接:http://jsfiddle.net/jhqjumgL/1/

我想这是自我解释,我需要这里所有按钮垂直居中,但按钮与textarea配对由于某种原因决定在底部休息,任何想法如何解决？