fn:intersperse → fn:join, array:join($arrays, $separator)

[ChristianGruen]

With string-join, you can create a string for multiple strings, optionally interspersed with a separator. array:join can be used to create an array from multiple arrays.

fn:intersperse, which has been added to the XQuery 4 draft, does something very similar, and early feedback indicates that the function is useful, but easily to overlook due to its name.

I propose to unify the functions by…

1. renaming fn:intersperse to fn:join;
2. adding a parameter to array:join: $separator as array(*)* := (); and
3. allowing a separator sequence for fn:string-join: $separator as xs:string* := ().

Examples

Query	Result	Info
string-join(('1','2','3'), '-')	'1-2-3'	existing syntax
array:join([[1],[2],[3]], ['-'])	[1,'-',2,'-',3]	new
join((1,2,3), '-')	(1,'-',2,'-',3)	now: intersperse((1,2,3),'-')
string-join(('1','2','3'))	'123'	existing syntax
array:join([[1],[2],[3]])	[1,2,3]	existing syntax
join((1,2,3))	(1,2,3)	now: intersperse((1,2,3)) (or just (1,2,3))
string-join(('1','2','3'), ('-','+')	'1-+2-+3'	new
array:join([[1],[2],[3]], ['-','+'])	[1,'-','+',2,'-','+',3]	new
join((1,2,3), ('-','+'))	(1,'-','+',2,'-','+',3)	now: intersperse((1,2,3),('-','+'))

[benibela]

renaming fn:intersperse to fn:join;

Could also call it sequence-join or items-join, then it is more consistent with string-join

items-join variant would also be consistent with items-after

adding a parameter to array:join: $separator as array() := (); and

or it could be a sequence.

array:join([1,2,3], '-') to make it [1,'-',2,'-',3]

[ChristianGruen]

Could also call it sequence-join or items-join, then it is more consistent with string-join

I suggested fn:join as we already have array:join and various other sequence functions that don’t include sequence.

items-join variant would also be consistent with items-after

The items- functions will probably be renamed:

https://qt4cg.org/pr/855/xpath-functions-40/Overview.html#func-subsequence-after https://github.com/qt4cg/qtspecs/issues/844#issuecomment-1826276165

or it could be a sequence. array:join([1,2,3], '-') to make it [1,'-',2,'-',3]

I thought about this, but then it wouldn’t be possible to include multiple arrays.

[joewiz]

+1 to fn:join (and array:join)

[michaelhkay]

I'm still a little uneasy that for many people with a database background, join means relational equijoin.

[ChristianGruen]

I noticed that during XML Prague the PRG-required label was added to this issue.

Does someone remember which of my suggestions were regarded as necessary? Would it be helpful if I create a PR for my initial proposal?

[michaelhkay]

Does someone remember

Not I, I'm afraid.