From: Tom Lane <tgl@sss.pgh.pa.us>
To: Thomas Lockhart <lockhart@alumni.caltech.edu>
Cc: Axel at ansonic <goddyna@ansonic.com.au>
Cc: pgsql-interfaces@postgreSQL.org, "Ross J. Reedstrom" <reedstrm@wallace.ece.rice.edu>
Cc: blackw@sfu.ca
Subject: Re: [INTERFACES] Bug in parser?
Date: Tue, 08 Feb 2000 01:42:13 -0500
Message-ID: <405.949992133@sss.pgh.pa.us> (raw)
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>
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-interfaces@postgresql.org
Cc: tgl@sss.pgh.pa.us, lockhart@alumni.caltech.edu, goddyna@ansonic.com.au, reedstrm@wallace.ece.rice.edu, blackw@sfu.ca
Subject: Re: [INTERFACES] Bug in parser?
In-Reply-To: <405.949992133@sss.pgh.pa.us>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox