Re: string_to_array with an empty input string - Mailing list pgsql-hackers

From Tom Lane
Subject Re: string_to_array with an empty input string
Date
Msg-id 7639.1281544612@sss.pgh.pa.us
Whole thread Raw
In response to Re: string_to_array with an empty input string  ("David E. Wheeler" <david@kineticode.com>)
Responses Re: string_to_array with an empty input string  (Robert Haas <robertmhaas@gmail.com>)
Re: string_to_array with an empty input string  ("David E. Wheeler" <david@kineticode.com>)
List pgsql-hackers
"David E. Wheeler" <david@kineticode.com> writes:
> On Aug 11, 2010, at 7:41 AM, Tom Lane wrote:
>> So maybe we need to revisit the issue.  Pavel was claiming that
>> switching to a zero-element array result was a no-brainer, but evidently
>> it isn't so.  Is anybody still excited about the alternatives?

> % perl -E 'say q{"}, join(",", ""), q{"}'
> ""
> % ruby -e 'puts %q{"} + [""].join(",") + %q{"}'
> ""
> % python -c 'print "\"" + ",".join([""]) + "\""'
> ""

> I believe those are all "", rather than '"' + undef + '"'.

If you believe my previous opinion that the design center for these
functions is arrays of numbers, then a zero-entry text[] array is what
you want, because you can successfully cast it to a zero-entry array of
integers or floats or whatever.  Returning a single empty string will
make those cases fail.  So at the moment I'm on the side of the fence
that says zero-entry array is the best answer.
        regards, tom lane


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