perl -MO=Concise,-exec -e "grep { 1; $1 eq $_ } @a"
1  <0> enter v
2  <;> nextstate(main 1 -e:1) v:{
3  <0> pushmark s
4  <#> gv[*a] s
5  <1> rv2av[t4] lKM/1
6  <@> grepstart K
7  <|> grepwhile(other->8)[t5] vK
8      <0> enter s
9      <;> nextstate(main 2 -e:1) v
a      <#> gvsv[*1] s
b      <#> gvsv[*_] s
c      <2> seq sK/2
d      <@> leave sKP
           goto 7
e  <@> leave[1 ref] vKP/REFC