Re: PL/pgSQL 'i = i + 1' Syntax

Mark Dilger wrote:
> David Wheeler wrote:
>
>>Hellow PostgreSQL hackers,
>>
>>Quick question. Why does the 'i = i + 1' syntax work in this PL/pgSQL
>>function?
>>
>>try=# CREATE OR REPLACE FUNCTION inc_by_two(
>>try(# upfrom int,
>>try(# upto int
>>try(# ) RETURNS SETOF INT AS $$
>>try$# BEGIN
>>try$# FOR i IN upfrom..upto LOOP
>>try$# RETURN NEXT i;
>>try$# i = i + 1;
>>try$# END LOOP;
>>try$# END;
>>try$# $$ LANGUAGE 'plpgsql';
>>CREATE FUNCTION
>>try=# select * from inc_by_two(1,10);
>>inc_by_two
>>------------
>> 1
>> 3
>> 5
>> 7
>> 9
>>(5 rows)
>>
>>Someone posted a PL/pgSQL function in my blog with this syntax, which
>>is how I know about it, but I couldn't find it documented anywhere. Is
>>it a special exception for loop variables, perhaps?
>>
>>Thanks,
>>
>>David
>>
>>---------------------------(end of broadcast)---------------------------
>>TIP 2: Don't 'kill -9' the postmaster
>>
>
>
> The syntax for assignment is:
>
> i := i + 1
>
> what you are doing is merely comparison. Since you are not using the results of
> the comparison, it is a no-op.
>
> mark

So I don't know why it works for you. I wrote the following, and it also
increments the variable:

CREATE OR REPLACE FUNCTION weird () RETURNS SETOF INT AS $$
DECLARE
i integer;
BEGIN
i := 0;
return next i;
i = i + 1;
return next i;
i = i + 1;
return next i;
return;
END;
$$ LANGUAGE plpgsql;

So I don't think it has anything to do with loop variables, specifically.

mark