Re: add function argument names to regex* functions. - Mailing list pgsql-hackers

From Tom Lane
Subject Re: add function argument names to regex* functions.
Date
Msg-id 1763682.1712090733@sss.pgh.pa.us
Whole thread Raw
In response to Re: add function argument names to regex* functions.  (jian he <jian.universality@gmail.com>)
Responses Re: add function argument names to regex* functions.
List pgsql-hackers
jian he <jian.universality@gmail.com> writes:
> On Thu, Jan 18, 2024 at 4:17 PM Peter Eisentraut <peter@eisentraut.org> wrote:
>> Reading back through the discussion, I wasn't quite able to interpret
>> the resolution regarding Oracle compatibility.  From the patch, it looks
>> like you chose not to adopt the parameter names from Oracle.  Was that
>> your intention?

> per committee message:
> https://git.postgresql.org/cgit/postgresql.git/commit/?id=6424337073589476303b10f6d7cc74f501b8d9d7
> Even if the names are all the same, our function is still not the same
> as oracle.

The fact that there's minor discrepancies in the regex languages
doesn't seem to me to have a lot of bearing on whether we should
follow Oracle's choices of parameter names.

However, if we do follow Oracle, it seems like we should do that
consistently, which this patch doesn't.  For instance, per [1]
Oracle calls the arguments of regex_substr

    source_char,
    pattern,
    position,
    occurrence,
    match_param,
    subexpr

while we have

    string,
    pattern,
    start,
    N,
    flags,
    subexpr

The patch proposes to replace "N" with "occurrence" but not touch
the other discrepancies, which seems to me to be a pretty poor
choice.  "occurrence" is very long and difficult to spell correctly,
and if you're not following Oracle slavishly, exactly what is the
argument in its favor?  I quite agree that Oracle's other choices
aren't improvements over ours, but neither is that one.

On the whole my inclination would be to stick to the names we have
in the documentation.  There might be an argument for changing "N"
to something lower-case so you don't have to quote it; but if we do,
I'd go for, say, "count".

            regards, tom lane

[1]
https://docs.oracle.com/en/database/oracle/oracle-database/23/sqlrf/REGEXP_SUBSTR.html#GUID-2903904D-455F-4839-A8B2-1731EF4BD099



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