Re: patch: to_string, to_array functions

https://commitfest.postgresql.org/action/patch_view?id=300

Why did you add to_string() and to_array() functions though we already
have string_to_array() and array_to_string() functions? I prefer adding
three arguments version of string_to_array() instead of to_array().
Please notice me if you think to_string() and to_array() are better names
for the feature. For example, compatibility for other databases.

* string_to_array( str text, sep text, nullstr text DEFAULT NULL )
is compatible with the existing string_to_array( str, sep ), and
"nullstr => 'NULL'" will be same as your to_array().

* array_to_string( arr anyarray, sep text, nullstr text DEFAULT NULL )
is compatible with the existing array_to_string(); separator also ignored
when nullstr is NULL. "nullstr => ''" (an empty string) will be same as
your to_array().

--
Itagaki Takahiro