Re: patch: to_string, to_array functions - Mailing list pgsql-hackers

2010/7/21 Robert Haas <robertmhaas@gmail.com>:
> On Wed, Jul 21, 2010 at 12:08 PM, Pavel Stehule <pavel.stehule@gmail.com> wrote:
>>>> I am thinking so we have to do decision about string_to_array and
>>>> array_to_string deprecation first. If these function will be
>>>> deprecated, then we can use a similar names (and probably we should to
>>>> use a similar names) - so text_to_array or array_to_string can be
>>>> acceptable. If not, then this discus is needless - then to_string and
>>>> to_array have to be maximally in contrib - stringfunc is good idea -
>>>> and maybe we don't need thinking about new names.
>>>
>>> Well, -1 from me for deprecating string_to_array and array_to_string.
>>>
>>> I am not in favor of the names to_string and to_array even if we put
>>> them in contrib, though.  The problem with string_to_array and
>>> array_to_string is that they aren't descriptive enough, and
>>> to_string/to_array is even less so.
>>
>> I am not a English native speaker, so I have a different feeling.
>> These functions do array_serialisation and array_deseralisation, but
>> this names are too long. I have not idea about better names - it is
>> descriptive well (for me) text->array, array->text - and these names
>> shows very cleanly symmetry between functions. I have to repeat - it
>> is very clean for not native speaker.
>
> Well, the problem is that array_to_string(), for example, tells you
> that an array is being converted to a string, but not how.  And
> to_string() tells you that you're getting a string, but it doesn't
> tell you either what you're getting it from or how you're getting it.
> We already have a function to_char() which can be used to format a
> whole bunch of different types as strings; I can't see adding a new
> function with almost the same name that does something completely
> different.
>
> array_split() and array_join(), following Perl?  array_implode() and
> array_explode(), along the lines suggested by Brendan?

I have a problem with array_split - because there string is split. I
looked on net - and languages usually uses a "split" or "join". split
is method of str class in Java. So when I am following Perl, I feel
better with  just only "split" and "join", but "join" is keyword :( -
step back, maybe string_split X array_join ?

select string_split('1,2,3,4',',');
select array_join(array[1,2,3,4],',');

so my preferences:

1. split, join - I checked - we are able to create "join" function
2. split, array_join - when only "join" can be a problem
3. string_split, array_join - there are not clean symmetry, but it
respect wide used a semantics - string.split, array.join
4. explode, implode
5. array_explode, array_implode
-- I cannot to like array_split - it is contradiction for me.

Pavel

p.s. It is typical use case for packages - with it, we can have the
functions string.split() and array.join()

>
> --
> Robert Haas
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