Re: proposal: plpgsql - Assert statement - Mailing list pgsql-hackers

From Robert Haas
Subject Re: proposal: plpgsql - Assert statement
Date
Msg-id CA+Tgmoa7B1aPa7K+_pTgd6_wCy_X=DGs3Ma0sRKaHBG8OGirEw@mail.gmail.com
Whole thread Raw
In response to Re: proposal: plpgsql - Assert statement  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: proposal: plpgsql - Assert statement  (Pavel Stehule <pavel.stehule@gmail.com>)
List pgsql-hackers
On Mon, Nov 24, 2014 at 2:07 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Two comments on that:
>
> 1. What is the likely use-case for such a thing (considering SQL is not
> exactly friendly to pointers or reference types),

I happen to know that Oracle supports more possible LHS syntaxes in
PL/SQL than we do in PL/pgsql, including things like foo(1) := 3.
There is more than one problem with supporting that syntax in
PL/pgSQL, and I haven't heard anyone complaining about its absence.
But it doesn't have to be that thing particularly: anything that even
vaguely resembles a general expression syntax on the LHS is going to
run into this.

> and is it more
> interesting than new statements that we are going to reject on the grounds
> that we don't want to reserve any more plpgsql keywords?

Probably not, but my crystal ball isn't working too well today.

> 2. The actual behavior would be the same as it would be for the case of
> implicit-CALL that we discussed upthread.  Namely, that it'd work just
> fine as long as "foo" isn't any unreserved keyword.  So the net effect
> would be that plpgsql keywords would be sort of semi-reserved, much like
> col_name_keywords in the core grammar: you can use 'em as variable names
> but not necessarily as function names.  With the current behavior where
> they're fully reserved, you can't use them as either, not even where the
> context is completely unambiguous.  I have not heard anyone complaining
> that col_name_keyword is a dumb idea and we should make all keywords fully
> reserved.

I see.  Well, that sounds fine, then.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company



pgsql-hackers by date:

Previous
From: Robert Haas
Date:
Subject: Re: group locking: incomplete patch, just for discussion
Next
From: Pavel Stehule
Date:
Subject: polymorphic types - enforce casting to most common type automatically