Is tokenize($s) the same as tokenize($s, ' ')?

Question

https://www.w3.org/TR/xpath-functions/#func-tokenize explains about the single argument version of tokenize:

The one-argument form of this function splits the supplied string at whitespace boundaries.

and then goes on to define or explain that with

calling fn:tokenize($input) is equivalent to calling fn:tokenize(fn:normalize-space($input), ' ')) where the second argument is a single space character (x20)

However, when I try count(tokenize('1 2 3')), count(tokenize('1
2
3')) with Saxon or BaseX or XmlPrime I get 3 3 while the supposedly equivalent count(tokenize('1 2 3', ' ')), count(tokenize('1
2
3', ' ')) in all three implementations gives me 3 1.

So all three implementations seem to do with tokenize($s) what the textual explanation says ("splits the supplied string at whitespace boundaries") but it doesn't seem that the equivalence of fn:tokenize($input) and fn:tokenize(fn:normalize-space($input), ' ')) given in the spec holds up, if a space is literally passed in then only that single space is used as a separator and not whitespace boundaries.

Is that equivalence given in the spec as a definition of the single argument version wrong?

Answer 1

The call on normalize-space() replaces newlines by x20 space characters. So while count(tokenize('1
2
3', ' ')) gives 1, count(tokenize(normalize-space('1
2
3'), ' ')) gives 3.

The substitution of newlines and tabs by single spaces could have been achieved using a smarter regular expression, but the key thing that the call on normalize-space() achieves is to trim leading and trailing whitespace. For example tokenize(" red green blue ", "\s+") gives 5 tokens, but tokenize(" red green blue ") gives 3.