Re: add function argument names to regex* functions.

On Thu, Dec 28, 2023 at 6:25 AM Peter Eisentraut <peter(at)eisentraut(dot)org> wrote:
>
> On 27.12.23 17:53, jian he wrote:
> > similar to [1], add function argument names to the following functions:
> > regexp_like, regexp_match,regexp_matches,regexp_replace,
> > regexp_substr,regexp_split_to_array,regexp_split_to_table,regexp_count
>
> Note that these functions are a quasi-standard that is shared with other
> SQL implementations. It might be worth looking around if there are
> already other implementations of this idea.
>

turns out people do like calling functions via explicitly mentioning
function argument names, example: [0]
There are no provisions for the argument names.

I looked around the oracle implementation in [1], and the oracle regex
related function argumentation name in [2]
I use the doc [3] syntax explanation and add the related function names.

Current, regex.* function syntax seems fine. but only parameter `N`
seems a little bit weird.
If we change the function's argument name, we also need to change
function syntax explanation in the doc; vise versa.

QUOTE:
The regexp_instr function returns the starting or ending position of
the N'th match of a POSIX regular expression pattern to a string, or
zero if there is no such match. It has the syntax regexp_instr(string,
pattern [, start [, N [, endoption [, flags [, subexpr ]]]]]). pattern
is searched for in string, normally from the beginning of the string,
but if the start parameter is provided then beginning from that
character index. If N is specified then the N'th match of the pattern
is located, otherwise the first match is located.
END OF QUOTE.

maybe we can change `N` to occurrence. but `occurrence` is kind of verbose.

[0] https://stackoverflow.com/questions/33387348/oracle-named-parameters-in-regular-functions
[1] https://docs.oracle.com/en/database/oracle/oracle-database/23/sqlrf/REGEXP_SUBSTR.html#GUID-2903904D-455F-4839-A8B2-1731EF4BD099
[2] https://dbfiddle.uk/h_SBDEKi
[3] https://www.postgresql.org/docs/current/functions-matching.html#FUNCTIONS-POSIX-REGEXP