Re: proposal: plpgsql - Assert statement

On 18 November 2014 12:29, Pavel Stehule <pavel.stehule@gmail.com> wrote:

>> Why is that not a requirement for a less wordier form of IF?
>>
>> IF (something) THEN action
>
>
> statement IF is a control statement - and syntax, pattern for control
> statements in plpgsql is consistent. I don't want to break it (more,
> probably it is hardly implemented due problems in bison). PL/pgSQL, PL/SQL,
> Ada are well designed (in my opinion). Conditional statement has precedent
> in PL/pgSQL now. We support EXIT and CONTINUE WHEN, so we don't propose a
> new pattern, only reuse some existing.

I commend your wish to improve PL/pgSQL, I'm sorry to say that I just
don't see how this moves us forwards.

What this does is introduce a fairly restricted new feature that
removes backwards compatibility and takes us further away from Oracle
compatibility.

If I want to write an Assert style test that fits on a single line, just write
   PEFORM raise_error_when(boolean expression);

which requires a very short function like this
CREATE OR REPLACE FUNCTION raise_error_when(test boolean) returns void
language plpgsql
AS $$
  DECLARE
  BEGIN
     IF (test) THEN
          RAISE EXCEPTION 'assertion failure';
     END IF;
  END;
$$;

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 Simon Riggs                   http://www.2ndQuadrant.com/
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