Conditional ordering operators

Some times ago I've written a script which creates two operators:

@< - ascending ordering
@> - descending ordering

(here is the script conditional_ordering.sql)

It allows you to replace code like this

if <condition1> then
  for
      select <fields>
      from <tables>
      where <restrictions>
      order by
          field1 desc,
          field2
  loop
      <actions>
  end loop;
elsif <condition2> then
  for
      select <fields>
      from <tables>
      where <restrictions>
      order by
          field3,
          field1 desc,
          field2 desc
  loop
      <actions>
  end loop;
else
  for
      select <fields>
      from <tables>
      where <restrictions>
      order by
          field4
  loop
      <actions>
  end loop;
end if;

that way

for
  select <fields>
  from <tables>
  where <restrictions>
  order by
      case when <condition1> then
          @>field1
          @<field2
      when <condition2> then
          @<field3
          @>field1
          @>field2
      else
          @<field4
      end
loop
  <actions>
end loop;

It looks better, doesn't it?

Also it provides Oracle like OVER PARTITION effect

select * from (
  values
  (1.2, '2007-11-23 12:00'::timestamp, true),
  (1.4, '2007-11-23 12:00'::timestamp, true),
  (1.2, '2007-11-23 12:00'::timestamp, false),
  (1.4, '2007-01-23 12:00'::timestamp, false),
  (3.5, '2007-08-31 13:35'::timestamp, false)
) _
order by
  @<column1 ||
  case
  when column1 = 1.2 then @<column3
  when column1 = 1.4 then @>column3
  else
      @>column2
      @<column3
  end;

column1 |       column2       | column3
---------+---------------------+---------
   1.2 | 2007-11-23 12:00:00 | f
   1.2 | 2007-11-23 12:00:00 | t
   1.4 | 2007-11-23 12:00:00 | t
   1.4 | 2007-01-23 12:00:00 | f
   3.5 | 2007-08-31 13:35:00 | f
(5 rows)

Note that rows 1-2 and 3-4 have opposite order in third column.

p.s. Unfortunately I haven't manage yet with text fields because of
localization.

Here is the script conditional_ordering.sql