Re: WIP: default values for function parameters

2008/11/25 Tom Lane <tgl@sss.pgh.pa.us>:
> Peter Eisentraut <peter_e@gmx.net> writes:
>> On Monday 24 November 2008 23:21:15 Pavel Stehule wrote:
>>> Default parameters are implemented similar to variadic functions - so
>>> no changes on PL part - all changes are on caller part.
>
>> Then I don't understand why you need this special data type instead of using
>> an array of text with nulls for parameters without default.
>
> I'm not even sure you need to store any nulls.  We're going to require
> defaults to be provided for the last N parameters consecutively, right?
> So that's just what the array contents are.  Or maybe it's not an array
> at all but a single text item containing the representation of a List
> --- compare the storage of index expressions.  There shouldn't be any
> need to read the contents of the value during function resolution;
> an appropriate representation will have the number of non-defaultable
> parameters stored as a separate integer column.
>

this can be the most simple solution, I used special datatype because
a) I am afraid add more columns to system tables, b) I dislike
serialisation into text type, because simple select from this values
returns some "strange" values. But maybe I am thinking and searching
to much complicate solutions. I'll try to simplify patch.

Regards
Pavel Stehule

>                        regards, tom lane
>