% perl -MO=Concise -e 'print "Hello, $world!"'
a  <@> leave[1 ref] vKP/REFC ->(end)
1     <0> enter ->2
2     <;> nextstate(main 1 -e:1) v ->3
9     <@> print vK ->a
3        <0> pushmark s ->4
-        <1> ex-stringify sK/1 ->9
-           <0> ex-pushmark s ->4
8           <2> concat[t3] sKS/2 ->9
6              <2> concat[t2] sK/2 ->7
4                 <$> const[PV "Hello, "] s ->5
-                 <1> ex-rv2sv sK/1 ->6
5                    <#> gvsv[*world] s ->6
7              <$> const[PV "!"] s ->8