Implement string_to_array

[lmatz]

aka split, a fundamental operation,
wonder if there is any other workaround?

[lmatz]

For POC

[y-wei]

string_to_array ( string text, delimiter text [, null_string text ] ) → text[]
Splits the string at occurrences of delimiter and forms the resulting fields into a text array. If delimiter is NULL, each character in the string will become a separate element in the array. If delimiter is an empty string, then the string is treated as a single field. If null_string is supplied and is not NULL, fields matching that string are replaced by NULL. See also array_to_string.
string_to_array('xxyyzz', '~~', 'yy') → {xx,NULL,zz}

Do we need to support all 1, 2, or 3-parameter version?
No hard, tho

[lmatz]

it seems only the last parameter, null string, is optional, not sure if I understand you correctly?

The first two input arguments are necessary. We can first support the basic one without the last parameter if the last one introduces much complexity. It is the most common use case.

[y-wei]

Yes, my bad. The third parameter isn't a big problem yet I'm trying to solve the case where the second parameter is NULL...

[y-wei]

closed by merged #9289