title: Change the order of tuple fields
body: <p>As an example, lets say I load two different files into a pig script</p>
  
  <pre><code>A = LOAD 'file1' USING PigStorage('\t') AS (
      day:chararray,
      month:chararray,
      year:chararray,
      message:chararray);
  
  B = LOAD 'file2' USING PigStorage('\t) AS (
      month:chararray,
      day:chararray,
      year:chararry,
      message:chararray);
  </code></pre>
  
  <p>Now, notice the order of the fields is different, so if I combine them into one file <code>C = UNION A, B;</code> I get...</p>
  
  <pre><code>(2,OCT,2013,INFO INVALID USERNAME)
  (OCT,3,2013,WARN STACK OVERFLOW)
  </code></pre>
  
  <p>If for no other reason than to make the data easier to read, I'd like to reorder the fields, so that both of them follow a common format and have the same positional notation for each field.</p>
  
  <pre><code>(2,OCT,2013,INFO INVALID USERNAME)
  (3,OCT,2013,WARN STACK OVERFLOW)
  </code></pre>
  
  <p>This also crops up in a few other places with messages, levels, hosts, etc. It's not just date fields, I'd like to make everything "prettier" all around. </p>
  
  <p>In some weird pseudo-code, I'd be looking for something like:</p>
  
  <pre><code>D = FOREACH B
      REORDER (month,day,year) TO (day,month,year);
  </code></pre>
  
  <p>I haven't been able to find an example of anyone trying to do this and don't see a function that would do it. So maybe it's not possible and I'm alone here, but if anyone has any ideas I'd appreciate some hints.</p>