Re: [xsl] What the default datatype of an stylesheet parameter ?

[Michael Kay <mike@xxxxxxxxxxxx>]

> Thank you for your response Ken, but as said Michael my question was 
> about "always supplied parameters".
> But this make me think about another question : if no parameters is 
> supplied, I'm use to test it againts empty string with
> <xsl:if test="$foo=''"/>
> and it usually works.
> Is an empty sequence equal to an emty string?
> (maybe the equal operator tries to cast both part to the same type ?

The '=' operator compares two sequences, and returns true if there is a 
pair of values, one from each sequence, that are equal to each other. If 
one of the sequences is empty, the result will always be false.

However, I may have misinformed you in my previous response. The 
specification says:

"If an optional parameter has no select attribute and has an empty 
sequence constructor, and if there is no as attribute, then the default 
value of the parameter is a zero length string."

This is why the test $foo='' is working for you.

The default value changes to an empty sequence if an "as" attribute is 
present to declare the type. In this case the test to apply is 
test="empty($foo)".

Michael Kay
Saxonica