[PATCH] Explain generate_subscripts() more clearly

Hi,

the current documentation on generate_subscripts() uses a
"rectangular" example, i. e. where both arrays in question
have the same length (that is furthermore equal to the num-
ber of arrays, a "square" example so to speak :-)). To point
out that generate_subscripts () can be used for more complex
cases as well, please find attached patch.

Tim
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 3419440..2677db9 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -11427,21 +11427,22 @@ select generate_subscripts('{NULL,1,NULL,2}'::int[], 1) as s;
 -- presenting an array, the subscript and the subscripted
 -- value requires a subquery
 select * from arrays;
-         a
---------------------
+       a
+---------------
  {-1,-2}
- {100,200}
-(2 rows)
+ {100,200,300}
+(2 Zeilen)

 select a as array, s as subscript, a[s] as value
 from (select generate_subscripts(a, 1) as s, a from arrays) foo;
-   array   | subscript | value
------------+-----------+-------
- {-1,-2}   |         1 |    -1
- {-1,-2}   |         2 |    -2
- {100,200} |         1 |   100
- {100,200} |         2 |   200
-(4 rows)
+     array     | subscript | value
+---------------+-----------+-------
+ {-1,-2}       |         1 |    -1
+ {-1,-2}       |         2 |    -2
+ {100,200,300} |         1 |   100
+ {100,200,300} |         2 |   200
+ {100,200,300} |         3 |   300
+(5 Zeilen)

 -- unnest a 2D array
 create or replace function unnest2(anyarray)