C:\test>perl -MO=Terse
my $string = $shared_key . ' => ' . $shared_value;
^Z
LISTOP (0x191d964) leave [1]
    OP (0x191d948) enter
    COP (0x191d988) nextstate
    ## exception handler installed here!
    BINOP (0x191d9c4) sassign
    ## exception handler entered here and the entire subtree retried <<<------+
    ## critical section entered here (on second attempt)                      |
        BINOP (0x191d9e8) concat [5]                                          |
            BINOP (0x191da4c) concat [3]                                      |
                UNOP (0x191da90) null [15]                                    |
                    PADOP (0x191dab0) gvsv  GV (0x182435c) *shared_key        |
                    ## Exception triggered here by the access to shared data.-+
                SVOP (0x191da70) const [6] PV (0x1824374) " => "
            UNOP (0x191da0c) null [15]
                PADOP (0x191da2c) gvsv  GV (0x18243b0) *shared_value
        OP (0x191dad0) padsv [1]
    ## critical section exited here.
- syntax OK