XSLT 2.0 and XPath 2.0 Programmer's Reference, 4th Edition (332 page)

• Boolean operators
  and
  and
  or
  

Many of these operators behave in much the same way as similar operators in other languages. There are some surprises, though, because of the way XPath handles sequences, and because of the way it mixes typed and untyped data. So don't skip this chapter just because you imagine that everything about these operators can be guessed.

Arithmetic Operators

These operators are normally used to perform calculations on numbers, which may be of any of the numeric types:
xs:integer
,
xs:decimal
,
xs:float
, or
xs:double
. They are also overloaded to perform calculations on dates and durations.

Note that this section only describes arithmetic operators built in to the XPath syntax. These operators are complemented by a range of arithmetic functions in the standard function library, described in Chapter 13. The functions in this library include
abs()
,
ceiling()
,
floor()
,
round()
,
round-half-to-even()
,
sum()
,
max()
,
min()
, and
avg()
.

Syntax

The syntax of expressions using the arithmetic operators is defined by the following syntax productions in the XPath grammar.

Expression	Syntax
AdditiveExpr	MultiplicativeExpr (( + | - ) MultiplicativeExpr )*
MultiplicativeExpr	UnionExpr (( * | div | idiv | mod ) UnionExpr )*
UnaryExpr	( - | + )* PathExpr