anchor.diff:  ----
   SELECT LOWER(SPLIT(" ", line)) AS word FROM receiver
   ----
  +
  +In that case the function +lower+ would of course be applied to each of +split+
  +results.
   
   WARNING: Notice that function names are case insensitive but keep in mind that
   field names are _not_!
  
positive.code: 
  It will return from 1 (if the separator is not found) to many results.
  
  When a function outputs several results then as many tuple will be output by the operation as a whole. When the SELECT statement uses several functions returning multiple results, the Cartesian product of all those results is output.
  
  So for instance the output tuples of +split(" ", "foo bar"), 42+ would be:
  
    "foo", 42
    "bar", 42
  
  and the output tuples of +split(" ", "foo bar"), split(" ", "baz bam")+ would be:
  
    "foo", "baz"
    "foo", "bam"
    "bar", "baz"
    "bar", "bam"
  
  In our case we just want to split incoming field +line+ by spaces:
  
  
negative.code: 
  - Integer overflows;
  
  - Better parse errors;
  
  - Edition syntax-aware tools (such as context-aware suggestions, syntax
    highlighting...  Require more annotations during parsing).
  