Re: Implicit casts with generic arrays

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Joe Conway <mail(at)joeconway(dot)com>
Cc: Peter Eisentraut <peter_e(at)gmx(dot)net>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: Implicit casts with generic arrays
Date: 2007-06-06 20:22:42
Message-ID: 7529.1181161362@sss.pgh.pa.us
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Joe Conway <mail(at)joeconway(dot)com> writes:
> Tom Lane wrote:
>> Maybe I am missing something, but the only such construct I see in
>> SQL2003 is concatenation of arrays of equal rank. There is nothing
>> corresponding to array_prepend or array_append.

> Well, I've never claimed to be particularly good at interpreting the SQL
> spec, but as an example...

> <array concatenation> ::=
> <array value expression 1> || <array primary>
> <array primary> ::=
> <value expression primary> ::=
> <nonparenthesized value expression primary> ::=
> <unsigned value specification> ::=
> <unsigned literal> ::=
> <unsigned numeric literal>

> Doesn't this mean that array concatenation should include things like:
> <array value expression> || <unsigned numeric literal>

No, because the first syntax rule for that is

1) The declared type of <value expression primary> shall be an
array type.

However, assuming that the anynonarray idea works out, we can do that
and not worry about touching the array operators.

regards, tom lane

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