Re: proposal: PLpgSQL parallel assignemnt

2017-06-02 10:15 GMT+02:00 Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>:

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> 2017-06-02 10:06 GMT+02:00 Craig Ringer <craig(at)2ndquadrant(dot)com>:
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>> On 2 June 2017 at 15:51, Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> wrote:
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>> > a, b := fx();
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>> > Comments, notes, ideas?
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>> I'd be pretty happy to have
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>> (a, b) = (x, y);
>> (a, b) = f(x);
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>> which is SQL-esque.
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> This is not too far to my proposal - and it is fully adequate alternative.
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The ANSI form is related to SET or UPDATE commands - so in this case I see
classic languages style
https://en.wikipedia.org/wiki/Assignment_(computer_science) better. The
assign statement in PLpgSQL is not related to embedded SQL. If we introduce
SQL syntax and SET commands for schema variables then ( ) syntax is
perfect, but for := PLpgSQL I am not sure

It is maybe strange, but

SET (a,b) = (SELECT a,b FROM foo)

a, b := fx()

are sentences from two independent worlds and different syntax can be
correct (depends how much we would to integrate procedural and SQL worlds
.. 100% T-SQL, 80% SQL/PSM, ..20% PLpgSQL or 5%PL/SQL)

Regards

Pavel

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>> But what, if anything, does Ada do?
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> What I know, no, Ada has not this statement - but the design of OUT
> parameters in Ada absolutely different than PostgreSQL - so in this case we
> cannot to use Ada language as our base :(
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> Regards
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> Pavel
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>
>>
>> --
>> Craig Ringer http://www.2ndQuadrant.com/
>> PostgreSQL Development, 24x7 Support, Training & Services
>>
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