Re: Add generate_series(numeric, numeric)

Thanks for the review. Attached the formatted patch according to your
suggestion.

- numeric datatype is large, but there are limitations. According to doc,
>> the limit is: up to 131072 digits before the decimal point; up to 16383
>> digits after the decimal point. How can we check if the next step
>> overflows? As a comparison, in int.c, generate_series_step_int4 checks if
>> its overflows, and stop the next call by setting step to 0. Should we do
>> that?
>>
> Yes we should.
>

how can we check the overflow after add_var?
(in int.c, the code checks for integer calculation overflow, that wraps the
result to negative value)

in numeric.sql regression test, i've added this query:
select (i / (10::numeric ^ 131071))::numeric(1,0)
from generate_series(-9*(10::numeric ^ 131071),
9*(10::numeric ^ 131071),
(10::numeric ^ 131071))
as a(i);

Because the doc notes that the maximum numeric digit before decimal point
is 131072, i hope this query covers the overflow case (in the last value it
will generate, if we add 9 x 10^13071 with 10^13071, add_var will
overflows). But in my tests, that isn't the case. The code works without
any error and returns the correct rows:

numeric
---------
-9
-8
-7
-6
-5
-4
-3
-2
-1
0
1
2
3
4
5
6
7
8
9
(19 rows)

Regards,
--
Ali Akbar