Operators

All operators known from C are available, with the following exceptions:

• assignment is a statement, not an operator
• no comma operator
• no ? : operator
• no cast or sizeof operator
• no pointer-related operators (&, ->, etc.)
• / acts a mask operator (see below) when the left operand is an IPv4 or IPv6 address, e.g. 1.2.3.4/8, 1.2.3.4:8, and 1.0.0.0 are all equivalent.

The following new operators have been added:

• the mask operator value:$[$left$][$:$[$right$]]$

  value:left

  zeroes all bits but the upper left

  value: :right

  zeroes all bits but the lower right.

  Note that there is a syntactical ambiguity between the zero IPv6 address (::) and this form of the mask operator. It is therefore recommended to always put a space between the two colons if using the mask operator.

  value:left:right

  zeroes all bits but the next right after skipping the upper left

  When using an integer or an IPv4 address, the value is always considered to have 32 bits when counting ``upper'' bits. When using an IPv6 address, the value is considered to have 128 bits.
• unit qualifiers (see above)
• relational operators and plus also work on strings
• the host operator host integer or host string, which returns an IPv4 address. When used on a string or string expression, host performs a host name lookup to obtain the address.
• the host4 operator, which is equivalent to the host operator described above
• the host6 operator, which works like host, but for IPv6 addresses instead of IPv4 addresses
• the precond operator, see section 3.6

Operator precedence is exactly as in C. In order to leave the precedence of C operators undisturbed, the mask operator and unit qualifiers have been given the highest precedence, while host, host4, host6, and precond can be used like functions.