Stack overflow in HOF query

[Cezar Andrei]

In zorba-2.9 execute:

declare function local:f($x as xs:integer)
{
  $x+1
};

declare function local:for-each($seq, $f) {
  if (fn:empty($seq))
  then ()
  else $f(fn:head($seq)), local:for-each(fn:tail($seq), $f)
};

local:for-each( (1,2,3), fn:function-lookup(xs:QName('local:f'), 1) )

Result:
(no URI):9,27: Zorba error [zerr:ZXQP0003]: internal error: stack overflow

[Sorin Marian Nasoi (sorin.marian.nasoi)]

Nicolai implemented teh HOF functions used in this example so I reassigned the bug to him.

[Nicolae Brinza (nbrinza)]

It's not a bug, Zorba behaves correctly, it should really do a stack overflow with this query.

To get the desired behavior and get rid of the of the overflow, the line

    else $f(fn:head($seq)), local:for-each(fn:tail($seq), $f)

should be changed to:

    else ($f(fn:head($seq)), local:for-each(fn:tail($seq), $f))

[Cezar Andrei (cezar-andrei)]

The code is copied from the 21 May 2013 Candidate Recommendation:
http://www.w3.org/TR/xpath-functions-30/#func-for-each

Maybe Gishlain should take a look at it.

[Nicolae Brinza (nbrinza)]

I've opened this W3C bug for the F&O spec -- https://www.w3.org/Bugs/Public/show_bug.cgi?id=22302

[Nicolae Brinza (nbrinza)]

Michael Kay fixed the code snippet -- https://www.w3.org/Bugs/Public/show_bug.cgi?id=22302#c1 . I assume it didn't get into the Working draft yet.

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