Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2])
	by hub.org (8.9.3/8.9.3) with ESMTP id BAA33490
	for <pgsql-interfaces@postgreSQL.org>;
	Tue, 8 Feb 2000 01:42:39 -0500 (EST)
	(envelope-from tgl@sss.pgh.pa.us)
Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1])
	by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id BAA00408;
	Tue, 8 Feb 2000 01:42:14 -0500 (EST)
To: Thomas Lockhart <lockhart@alumni.caltech.edu>
cc: Axel at ansonic <goddyna@ansonic.com.au>, pgsql-interfaces@postgreSQL.org,
	"Ross J. Reedstrom" <reedstrm@wallace.ece.rice.edu>, blackw@sfu.ca
Subject: Re: [INTERFACES] Bug in parser? 
In-reply-to: <389FB27B.1F9702BD@alumni.caltech.edu> 
References: <NABBLEOMMPNHHMBPOBPFIENAFFAA.goddyna@ansonic.com.au>
	<27734.949981876@sss.pgh.pa.us>
	<389FB27B.1F9702BD@alumni.caltech.edu>
Comments: In-reply-to Thomas Lockhart <lockhart@alumni.caltech.edu>
	message dated "Tue, 08 Feb 2000 06:06:51 +0000"
Date: Tue, 08 Feb 2000 01:42:13 -0500
Message-ID: <405.949992133@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>

Thomas Lockhart <lockhart@alumni.caltech.edu> writes:
> Pretty sure that the SQL92 rules for the "string across lines" is more
> restrictive than just allowing spaces between double quotes; you
> actually need something close to a line break.
>
> select * from "T1" "A1";
>
> would do horrible things if I interpret your suggestion correctly.

No, because we're talking about string literals (single quotes) not
double-quoted names.  Is there harm in interpreting
	select 'a string' ' literal';
as
	select 'a string literal';
?  And if so, why does it suddenly become OK if I write it as
	select 'a string'
	       ' literal';

The SQL92 spec isn't particularly transparent about this, but if I am
looking at the right syntax items, we have

         <character string literal> ::=
              [ <introducer><character set specification> ]
              <quote> [ <character representation>... ] <quote>
                [ { <separator>... <quote> [ <character representation>... ] <quote> }... ]

         <separator> ::= { <comment> | <space> | <newline> }...

which sure as heck looks like you can write either newline or just
plain space between 'a string' and ' literal' and get the same answer.

A couple other items:

* I see why xqdouble has to be separate from xqcat; the former
produces a single quote in the represented string, the latter doesn't.
So xqcat must at least be defined as
	xqcat	{quote}{space}{space}*{quote}
to allow it to be distinguished from xqdouble.

* I see that the spec allows comments between segments of a string
literal.  This works in current code:

regression=# select 'a string' -- zzz
regression-# ' literal';
     ?column?
------------------
 a string literal
(1 row)

but I'm durned if I see where that behavior is implemented.
Do you?

			regards, tom lane