[XSL-LIST Mailing List Archive Home] [By Thread] [By Date]

Re: [xsl] The specification of the standard function fold-left

Subject: Re: [xsl] The specification of the standard function fold-left
From: "Dimitre Novatchev dnovatchev@xxxxxxxxx" <xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>
Date: Sun, 22 Jun 2014 06:21:00 -0000

On Sat, Jun 21, 2014 at 11:08 PM, Wolfgang Laun
wolfgang.laun@xxxxxxxxx <xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>
>> "As a consequence of the function signature and the function calling
>> rules, a type error occurs if the supplied function $f cannot be
>> applied to two arguments, where the first argument is either the value
>> of $zero or the result of a previous application of $f, and the second
>> is $seq or any trailing subsequence of $seq"
>> The signature of the function fold-left is specified as:
>> fn:fold-left($seq as item()*,
>>                  $zero as item()*,
>>                  $f as function(item()*, item()) as item()*) as item()*
>> The above quoted paragraph violates the signature, because the
>> argument $f, as specified cannot have as its second argument a
>> sequence -- the type of the second argument of $f must be item(). But
>> the above quoted paragraph says "...the second is $seq or any trailing
>> subsequence of $seq".
> Since each call of $f is done with fn:head($seq), and the restriction
> defined here refers to the second argument of fn:fold-left I see no
> problem with this text.

The issue is that by definition the second argument of $f is of type
item()  -- this means that $f cannot accept as its second argument
"$seq or any trailing
subsequence of $seq".

And you are referring to the XQuery and XSLT code published in the
"Rules" section -- this code is correct. The issue is with the text of
the "Error Conditions" section -- more precisely, the end of the

Dimitre Novatchev
Truly great madness cannot be achieved without significant intelligence.
To invent, you need a good imagination and a pile of junk
Never fight an inanimate object
To avoid situations in which you might make mistakes may be the
biggest mistake of all
Quality means doing it right when no one is looking.
You've achieved success in your field when you don't know whether what
you're doing is work or play
To achieve the impossible dream, try going to sleep.
Facts do not cease to exist because they are ignored.
Typing monkeys will write all Shakespeare's works in 200yrs.Will they
write all patents, too? :)
I finally figured out the only reason to be alive is to enjoy it.

Current Thread