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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>
wrote:
>> "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
sentence.



-- 
Cheers,
Dimitre Novatchev
---------------------------------------
Truly great madness cannot be achieved without significant intelligence.
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I finally figured out the only reason to be alive is to enjoy it.


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