Local Variables

Local variables can be defined and used inside of any unlang processing section. A local variable is used any time a "temporary" variable is needed. Local variables exist only within a particular section (i.e. scope), and cannot be sent in a packet over the network.

Syntax

<keyword> {
    <data-type> <name>
    ...

    [ statements ]
}

<keyword>: One of case, else, elsif, foreach, group, if ,limit, or timeout. Local variables are forbidden in all other locations.
<data-type>: A "leaf" data type. Structural types such as group, struct, tlv, etc. are not allowed.
<name>: A unique name for the local variable. This name cannot be the same as any previously-defined local variable in the same scope, and it cannot be the same as any attribute defined in the current protocol dictionary.

Multiple local variables may be defined. All definitions must be at the top of a section.

[ statements ]: The unlang commands which will be executed. The local variable can be used, edited, modified, etc. within these statements.

Local variables cannot be deleted. Multiple local variables of the same name cannot be used. The local variables exist in their own list, and cannot be added to the normal lists request, reply, control, etc.

Local variables are not automatically created. There is no way to automatically determine what the "right" value is for a local variable. Instead, they are declared at the top of a block, and are created only when they are first assigned a value.

Local variables cannot be deleted. When the current scope exits, the local variable is deleted and is no longer accessible.

Example

if (&User-Name == "bob") {
    uint32 len

    &len := %length(%{User-Name})

    &Reply-Message := "Length of %{User-Name} is %{len}"
}

In v3 the default dictionaries included a series of Tmp-* attributes. These are no longer necessary, and should not be used.

Local variables exist on only if they have been created

if (&User-Name == "bob") {
    # declare "len" as ALLOWED to be used
    uint32 len

    # this test ALWAYS fails, as "len" has not been assigned a value
    if (&len) {
       ...
    }

    #  "len" is created, and can now be used
    &len := %length(%{User-Name})

    &Reply-Message := "Length of %{User-Name} is %{len}"
}

The variable declaration and assignment must be sepaarted. Constructions like uint32 len = %length(%{User-Name}) are not allowed.