[xsl] () equivalent to () ?

Subject: [xsl] () equivalent to () ?
From: Frans Englich <frans.englich@xxxxxxxxx>
Date: Mon, 22 Aug 2005 13:03:28 +0000

Is the empty sequence equal to itself?

I would say yes, because what charactarizes the empty sequence, its length and 
its members(AFAICT), is always the same. IIRC, the empty sequence is a 
constant value and hence it must by common principles be identical to itself.

As a consequence, the expression "data( () )" should be equivalent to its 
argument, "()", the empty sequence.

However, testing this theory in practice in a host language such as XSLT 2.0 
is impossible(?) since all comparison operators returns the empty sequence 
when an operand is the empty sequence.

I wonder, does the problematism I encircle have an impact in a real world 
scenario? (e.g, is it something more than a confusing word game?)

I am rather empty on this topic and I guess that means... euhm.. that I am 
equivalent to..



The specs seems to be inconsistent in this area, sometimes the wording reads 
"if ... then the empty sequence is returned," and in other cases it reads "If 
the operand is an empty sequence".
In other words, sometimes "empty sequence" is referred to as a constant value, 
while in other cases as a type(or however one chooses to interpret this 
difference in definite form).

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