$
variable
anonymous state variable
https://docs.raku.org/language/variables#The_$_variable
The anonymous state variable can be used without an explicit
C<state> declaration.  Each reference to C<$> within a lexical
scope is in effect a separate variable.

$_
variable topic
the current topic
https://docs.raku.org/language/variables#The_$__variable
Every block has its own topic variable.  It can be set directly,
or is set automatically with statements such as C<given>, C<with>
and C<for>.

$/
variable regex
the current regex match result
https://docs.raku.org/language/variables#The_$/_variable
Results of many actions related to regular expressions set
this variable.  Each C<Routine> has its own copy of it.  It
also provides C<Positional> functionality, so that C<$/[0]>
refers to the first positional capture (which can be shortened
to C<$0>).  And it also provides the C<Associative> functionality
so that that C<$/<foo>> refers to the named capture "foo"
(which can be shortened to C«$<foo>».

$!
variable
the current error variable
https://docs.raku.org/language/variables#The_$!_variable
Typically contains the last caught exception seen.  Each
C<Routine> has its own copy of it.


contains all variables that are always available for usage in a
lexical scope.
