zapzap, `!!`, %zpzp
============================

Crash

`!?` is a natural rune that always crashes.

Produces
--------

Twig: `[%zpzp ~]`

Sample
------

Always ignored

Tall form
---------

None

Wide form
---------

    !!

Irregular form
--------------

None

Examples
--------

Frequently used as sentinel

    ~zod/try=> !!
    ! exit
    ~zod/try=> =|(a=(unit) ?^(a !! %none))
    %none
    ~zod/try=> :type; =|(a=(unit) ?^(a !! %none))
    %none
    %none
    ~zod/try=> ?+('a' !! %a 1, %b 2)
    1
    ~zod/try=> ?+('c' !! %a 1, %b 2)
    ! exit