[HACKERS] TODO for plpgsql: RETURN should accept arbitrary composite expressions

[Josh Berkus]

Folks,

On 8.0.4 and 8.1b4 given:

create type return_value as (
id INTEGER,
message TEXT
);

this function:

create function return_test (
vuser INT, vsession INT
) returns return_value as $fnc$
declare vtemp return_value;
begin
vtemp := row( -1, 'bad' );
return vtemp;
end; $fnc$ language plpgsql;

works, but this function:

create function return_test_2 (
vuser INT, vsession INT
) returns return_value as $fnc$
begin
vtemp := row( -1, 'bad' );
end; $fnc$ language plpgsql;

gives this error at run time:

ERROR:  syntax error at or near vtemp at character 1
QUERY:  vtemp := row( -1, 'bad' )
CONTEXT:  PL/pgSQL function return_test_2 line 2 at SQL statement
LINE 1: vtemp := row( -1, 'bad' )

... the problem seems to be that RETURN will accept variables and constants 
but not arbitrary composites.  We should fix that eventually.   Can we put 
it on the TODO list?



-- 
--Josh

Josh Berkus
Aglio Database Solutions
San Francisco

---(end of broadcast)---
TIP 1: if posting/reading through Usenet, please send an appropriate
   subscribe-nomail command to [EMAIL PROTECTED] so that your
   message can get through to the mailing list cleanly

Re: [HACKERS] TODO for plpgsql: RETURN should accept arbitrary composite expressions

[Josh Berkus]

Folks,

Two corrections:

The second example was the wrong code, it should have been this function:

create function return_test_2 (
vuser INT, vsession INT
) returns return_value as $fnc$
begin
return row( -1, 'bad' );
end; $fnc$ language plpgsql;

Also, this issue is documented, but I believe that it still needs fixing, 
as current behavior is cumbersome and unintuitive:

When returning a scalar type, any expression can be used. The expression's 
result will be automatically cast into the function's return type as 
described for assignments. To return a composite (row) value, you must 
write a record or row variable as the expression.

-- 
--Josh

Josh Berkus
Aglio Database Solutions
San Francisco

---(end of broadcast)---
TIP 2: Don't 'kill -9' the postmaster