Add or subtract numerical values.
The following construct(s) refer to this construct:
The AdditiveExpr provides the usual arithmetic operations
for adding and subtracting numerical values. Each operand is
atomized so that
it is either a single atomic value or an empty sequence. If one of the operands
is atomized to an empty sequence, the result of the operation is also an empty
sequence.
A sequence of expressions that consists of string and numeric literals:
(59 - 17)
As integer literals the operands are already atomic values and of valid
type for the operator. Tamino returns the expected result 42.
Compute the years, in which all patients turned 18 years:
for $a in input()/patient/born return $a + 18
The variable $a is bound to the
born element. After atomization the addition can be
performed.
