Functions, operators, and data types for XPath 2.0

I have made the following changes to the function library:

• The count() and sum() functions now ork on any sequence, and new functions avg(), min(), and max() are provided.
• Added ends-with()
• Added upper-case() and lower-case(). These use the rules defined by the Java default locale
• Added properties "product-name" and "product-version" to system-property()
• Changed key() so that the second argument can be any sequence; each member of the sequence is converted to a string and treated as a potential key value
• Changed document() so that the first argument can be any sequence; each member of the sequence can be a URI of a document to be loaded.
• The node-set() function in the EXSLT common module is now a no-op; the object-type() function returns one of "sequence", "boolean", "number", "string", or "external".
• Changed highest() and lowest() in the EXSLT math module to work on arbitrary sequences.
• Added exists() and empty(), insert() and remove(), index-of() and sublist().
• Added not3() (three-valued not() function)
• Added string-pad() function
• Removed saxon:exists() and saxon:for-all(): these are superseded by the some and every constructs in XPath 2.0
• Added the compare() function: the third argument (collation) is initially mandatory, and must be a QName matching a saxon:collation element
• Added base-uri() function replacing the undocumented saxon:base-uri() extension function
• Added constructor functions as described in the XPath Functions and Operators specification: some of them don't do much yet, but float() is the only way of creating a single-precision floating point number.

Significant Omissions

In general, features of XSLT 2.0 and XPath 2.0 not listed above have not been implemented. In particular, these include:

• Backwards compatibility mode in XSLT
• The type attribute of xsl:variable, etc.
• Uniform handling of the empty sequence by functions and operators in XPath expressions
• XPath constructs related to types, for example instance of and cast as.