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* "format" function documentation fix
@ 2013-09-14 08:29 rudolf <stu3.1@eq.cz>
0 siblings, 1 reply; 6+ messages in thread
From: rudolf @ 2013-09-14 08:29 UTC (permalink / raw)
To: pgsql-docs
(Please CC me the reply, since I'm not subscribed to the list.)
Hi,
The last example from
http://www.postgresql.org/docs/9.3/static/functions-string.html#FUNCTIONS-STRING-FORMAT
- "examples using width fields and the - flag" seems to be incorrect,
see the attached patch.
Regards,
r.
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Attachments:
patch.diff (text/x-patch, 398B) download
--- doc/src/sgml/func.sgml.orig 2013-09-14 10:02:56.000000000 +0200
+++ doc/src/sgml/func.sgml 2013-09-14 10:03:25.000000000 +0200
@@ -3021,7 +3021,7 @@
<lineannotation>Result: </><computeroutput>|foo |</>
SELECT format('|%-*s|', -10, 'foo');
-<lineannotation>Result: </><computeroutput>|foo |</>
+<lineannotation>Result: </><computeroutput>| foo|</>
</screen>
</para>
* Re: "format" function documentation fix
@ 2013-09-17 08:49 Dean Rasheed <dean.a.rasheed@gmail.com>
parent: rudolf <stu3.1@eq.cz>
0 siblings, 1 reply; 6+ messages in thread
From: Dean Rasheed @ 2013-09-17 08:49 UTC (permalink / raw)
To: rudolf <stu3.1@eq.cz>; +Cc: pgsql-docs
On 14 September 2013 09:29, rudolf <stu3.1@eq.cz> wrote:
> (Please CC me the reply, since I'm not subscribed to the list.)
>
> Hi,
>
> The last example from
> http://www.postgresql.org/docs/9.3/static/functions-string.html#FUNCTIONS-STRING-FORMAT
> - "examples using width fields and the - flag" seems to be incorrect, see
> the attached patch.
>
No, the example is correct. Referring to the documentation above that:
If the width argument is negative, the result is left aligned (as
if the - flag had been specified) ...
This applies even if the "-" flag is also specified. So the last
example is meant to illustrate that 2 minuses don't make a plus here.
Regards,
Dean
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^ permalink raw reply [nested|flat] 6+ messages in thread
* Re: "format" function documentation fix
@ 2013-09-17 09:00 rudolf <stu3.1@eq.cz>
parent: Dean Rasheed <dean.a.rasheed@gmail.com>
0 siblings, 2 replies; 6+ messages in thread
From: rudolf @ 2013-09-17 09:00 UTC (permalink / raw)
To: Dean Rasheed <dean.a.rasheed@gmail.com>; +Cc: pgsql-docs
(Please CC me the reply, since I'm not subscribed to the list.)
Dean Rasheed wrote:
> On 14 September 2013 09:29, rudolf <stu3.1@eq.cz> wrote:
>> The last example from
>> http://www.postgresql.org/docs/9.3/static/functions-string.html#FUNCTIONS-STRING-FORMAT
>> - "examples using width fields and the - flag" seems to be incorrect, see
>> the attached patch.
>
> No, the example is correct. Referring to the documentation above that:
>
> If the width argument is negative, the result is left aligned (as
> if the - flag had been specified) ...
>
> This applies even if the "-" flag is also specified. So the last
> example is meant to illustrate that 2 minuses don't make a plus here.
That's very unusual, IMO. This behavior follows some SQL standard or is
it an invention of PostgreSQL?
Thanks,
r.
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^ permalink raw reply [nested|flat] 6+ messages in thread
* Re: "format" function documentation fix
@ 2013-09-17 10:41 Dean Rasheed <dean.a.rasheed@gmail.com>
parent: rudolf <stu3.1@eq.cz>
1 sibling, 0 replies; 6+ messages in thread
From: Dean Rasheed @ 2013-09-17 10:41 UTC (permalink / raw)
To: rudolf <stu3.1@eq.cz>; +Cc: pgsql-docs
On 17 September 2013 10:00, rudolf <stu3.1@eq.cz> wrote:
> (Please CC me the reply, since I'm not subscribed to the list.)
>
> Dean Rasheed wrote:
>>
>> On 14 September 2013 09:29, rudolf <stu3.1@eq.cz> wrote:
>>>
>>> The last example from
>>>
>>> http://www.postgresql.org/docs/9.3/static/functions-string.html#FUNCTIONS-STRING-FORMAT
>>> - "examples using width fields and the - flag" seems to be incorrect, see
>>> the attached patch.
>>
>>
>> No, the example is correct. Referring to the documentation above that:
>>
>> If the width argument is negative, the result is left aligned (as
>> if the - flag had been specified) ...
>>
>> This applies even if the "-" flag is also specified. So the last
>> example is meant to illustrate that 2 minuses don't make a plus here.
>
>
> That's very unusual, IMO. This behavior follows some SQL standard or is it
> an invention of PostgreSQL?
>
It's not part of the SQL standard, but it is based on C printf() and
friends from the Single UNIX Specification, see for example
http://pubs.opengroup.org/onlinepubs/7908799/xsh/fprintf.html
My reading of that is that "-" is to be treated as a flag, not as a
minus sign, so specifying it multiple times has the same effect as
specifying it once. On my linux box, the following both produce
left-justified output:
printf("'%-10s'\n", "foo");
printf("'%--10s'\n", "foo");
Regards,
Dean
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^ permalink raw reply [nested|flat] 6+ messages in thread
* Re: "format" function documentation fix
@ 2013-09-18 19:46 Pavel Stehule <pavel.stehule@gmail.com>
parent: rudolf <stu3.1@eq.cz>
1 sibling, 1 reply; 6+ messages in thread
From: Pavel Stehule @ 2013-09-18 19:46 UTC (permalink / raw)
To: rudolf <stu3.1@eq.cz>; +Cc: Dean Rasheed <dean.a.rasheed@gmail.com>; pgsql-docs
hello
2013/9/17 rudolf <stu3.1@eq.cz>
> (Please CC me the reply, since I'm not subscribed to the list.)
>
> Dean Rasheed wrote:
>
>> On 14 September 2013 09:29, rudolf <stu3.1@eq.cz> wrote:
>>
>>> The last example from
>>> http://www.postgresql.org/**docs/9.3/static/functions-**
>>> string.html#FUNCTIONS-STRING-**FORMAT<http://www.postgresql.org/docs/9.3/static/functions-string.html#FUNCTIONS-STRING-FORMAT;
>>> - "examples using width fields and the - flag" seems to be incorrect, see
>>> the attached patch.
>>>
>>
>> No, the example is correct. Referring to the documentation above that:
>>
>> If the width argument is negative, the result is left aligned (as
>> if the - flag had been specified) ...
>>
>> This applies even if the "-" flag is also specified. So the last
>> example is meant to illustrate that 2 minuses don't make a plus here.
>>
>
> That's very unusual, IMO. This behavior follows some SQL standard or is it
> an invention of PostgreSQL?
>
>
this is postgresql feature - standard doesn't support any similar
functionality - and printf is some like developer Esperanto. We
significantly reduced complexity of printf function and we modified basic
rules for usage in SQL, but some very typical rules - like format
placeholders, we share - we don't introduce own rules there.
Regards
Pavel Stehule
> Thanks,
>
> r.
>
>
>
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>
^ permalink raw reply [nested|flat] 6+ messages in thread
* Re: "format" function documentation fix
@ 2013-09-20 08:05 rudolf <stu3.1@eq.cz>
parent: Pavel Stehule <pavel.stehule@gmail.com>
0 siblings, 0 replies; 6+ messages in thread
From: rudolf @ 2013-09-20 08:05 UTC (permalink / raw)
To: Pavel Stehule <pavel.stehule@gmail.com>; +Cc: Dean Rasheed <dean.a.rasheed@gmail.com>; pgsql-docs
(Please CC me the reply, since I'm not subscribed to the list.)
Pavel Stehule wrote:
> 2013/9/17 rudolf
> Dean Rasheed wrote:
[...]
> This applies even if the "-" flag is also specified. So the last
> example is meant to illustrate that 2 minuses don't make a plus
> here.
>
> That's very unusual, IMO. This behavior follows some SQL standard or
> is it an invention of PostgreSQL?
>
> this is postgresql feature - standard doesn't support any similar
> functionality - and printf is some like developer Esperanto. We
> significantly reduced complexity of printf function and we modified
> basic rules for usage in SQL, but some very typical rules - like format
> placeholders, we share - we don't introduce own rules there.
Yes, as I already wrote to Dean (and forgot to cc the list), you are
right, the behavior is correct. Thanks for the explanation!
Kind regards,
r.
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^ permalink raw reply [nested|flat] 6+ messages in thread
end of thread, other threads:[~2013-09-20 08:05 UTC | newest]
Thread overview: 6+ messages (download: mbox mbox.gz follow: Atom feed)
-- links below jump to the message on this page --
2013-09-14 08:29 "format" function documentation fix rudolf <stu3.1@eq.cz>
2013-09-17 08:49 ` Dean Rasheed <dean.a.rasheed@gmail.com>
2013-09-17 09:00 ` rudolf <stu3.1@eq.cz>
2013-09-17 10:41 ` Dean Rasheed <dean.a.rasheed@gmail.com>
2013-09-18 19:46 ` Pavel Stehule <pavel.stehule@gmail.com>
2013-09-20 08:05 ` rudolf <stu3.1@eq.cz>
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