Re: [HACKERS] merging some features from plpgsql2 project

On 1/8/17 12:03 AM, Pavel Stehule wrote:

        BTW, I do wish you could change the label of the scope that
        arguments went into, so that you could use that label to refer
        to function parameters. If we allowed that it'd perhaps be the
        best of both worlds: you'd be guaranteed access to all auto
        variables and parameters, and that access wouldn't need to be
        tied to the function name (which can be both painful and error
        prone).


    We can talk about compiler directive.

    PRAGMA auto_variables_label(xxxx) -- require function scope only


If we know a list of all auto variables, then it can be on function or
block level - it can create aliases.

Oh, the problem is that if you have an argument with the same name as an auto variable you're in trouble.

Probably the easiest thing is to have a scope that sits above the scope containing the arguments, and then allow the user to rename both scopes if so desired. So in effect you'd end up with

<<plpgsql>> -- new scope
DECLARE
FOUND;
etc
BEGIN
  <<function_name>>
  DECLARE
  argument_1;
  argument_2;
  BEGIN
    -- User supplied block goes here, with optional label
  END;
END;

Alternatively, we could do...

<<function_name>>
DECLARE
FOUND;
etc
BEGIN
  DECLARE-- User's DECLARE
  argument_1;
  argomuent_2;
  -- User supplied declare code
  BEGIN -- User's BEGIN
  ....
END

That removes one level of nesting. It's probably better to go with the first option though, since it's simpler.

In both cases, I'd really like the ability to rename those blocks. #pragma would be fine for that.

--
Jim Nasby, Data Architect, Blue Treble Consulting, Austin TX
Experts in Analytics, Data Architecture and PostgreSQL
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