FOREACH中的嵌套双条件语句

Question

我有以下Pig Latin代码段（为了便于阅读，在多行格式化）：

data = LOAD 'some_file' 
  as (bid:chararray,
    pvs:long,
    paid:long,
    social:long,
    search:long,
    direct:long,
    morning:long,
    afternoon:long,
    evening:long,
    night:long,
    platform:long);

user_dedication = FOREACH (GROUP data BY pvs) 
  GENERATE 
    (group==1L?'one offs':
      (group<=10L:'between 1 and 10':
        (group<=100L?'between 10 and 100':'more than 100'))) as bin, 
    COUNT(pvs) as bids;

导致以下错误：

2014-05-22 19:10:22,418 [main] ERROR org.apache.pig.tools.grunt.Grunt - 
  ERROR 1200: <line 3, column 70>  
    Syntax error, unexpected symbol at or near 'group'

我可以＆＃34;修复＆＃34;通过改写以上内容：

tmp1 = FOREACH (GROUP data BY pvs) 
  GENERATE 
    group as pvs,
    (group==1L?'one offs':'else') as bin, 
    COUNT(bid_segments) as bids;
tmp2 = FOREACH tmp1 GENERATE 
  pvs, (bin=='else'?( pvs<=10L?'between 1 and 10':'else' ):bin) as bin, bids;
user_dedication = FOREACH tmp2 GENERATE 
  pvs, (bin=='else'?( pvs<=100L?'between 10 and 100':'more than 100' ):bin) as bin, bids;

对我来说这看起来像个直接的错误。为什么我不能编写嵌套的双条件语句？