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

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

Subject: [xsl] The specification of the standard function fold-left
From: "Dimitre Novatchev dnovatchev@xxxxxxxxx" <xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>
Date: Sun, 22 Jun 2014 02:31:41 -0000

 The section "16.2.3 fn:fold-left" of the W3C document "XPath and
XQuery Functions and Operators 3.0", contains this text:

"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".

Exactly the same paragraph is used in the specification of fold-right
-- and in that case the text is correct.

It seems that the paragraph was copied from the fold-right
specification into the specification of fold-left and this led to the
observed error.

Hope this would help and lead to a future correction.

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