optree output of crazier.pl (see https://gist.github.com/2499830)

gistfile1.txt

 >>> perl -MO=Concise,-exec crazier.pl 
1  <0> enter 
2  <;> nextstate(main 66 crazier.pl:4) v:%,*,&,{,$,2048
3  <{> enterloop(next->8 last->8 redo->4) v
4  <;> nextstate(PackageA 51 crazier.pl:7) v:%,*,&,{,$,2048
5  <{> enterloop(next->7 last->7 redo->6) v
6  <0> stub v
7  <2> leaveloop vK/2
8  <2> leaveloop vK/2
9  <;> nextstate(main 69 crazier.pl:41) v:%,*,&,{,$,2048
a  <{> enterloop(next->q last->q redo->b) v
b  <;> nextstate(PackageB 66 crazier.pl:42) v:%,*,&,{,$,2048
c  <0> pushmark s
d  <$> const(PV "PackageA") sP
e  <0> pushmark s
f  <$> gv(*PackageB::ISA) s
g  <1> rv2av[t2] lKPRM*/OURINTR,3
h  <2> aassign[t3] vKS
i  <;> nextstate(PackageB 68 crazier.pl:46) v:%,*,&,{,$,2048
j  <0> pushmark s
k  <$> const(PV "PackageB") sM
l  <0> pushmark sRM
m  <$> anoncode[CV ] lRM
n  <1> refgen lKM/1
o  <$> method_named(PV "configure") 
p  <1> entersub[t5] vKS/TARG,2
q  <2> leaveloop vK/2
r  <@> leave[1 ref] vKP/REFC
crazier.pl syntax OK