XSLT 2.0 and XPath 2.0 Programmer's Reference, 4th Edition (347 page)

NodeComp

is | << | >>

This means that all 15 operators listed here have the same priority. For all these operators the result of the expression is always an
xs:boolean
value. The reference to
RangeExpr
in the syntax can be ignored for now: it just refers to the next kind of expression in operator precedence order, which happens to be the range expression (of the form
1 to 10
) described in Chapter 10.

The biggest difference between the value comparison operators and the general comparison operators described on page 588 is that the value comparison operators always compare two atomic values with each other, whereas the general comparison operators can be used to compare sequences.

Permitted Operand Types

The detailed effect of the comparison depends on the types of the two operands. These must be compatible with each other. There are some data types that can be compared using the
eq
and
ne
operators but not the
lt
,
le
,
gt
, or
ge
operators. An example is
xs:QName
—you can test whether two
xs:QName
values are equal to each other but not whether one is less than the other.