Inside an OP

• BASEOP in op.h:

    OP* op_next;	/* next in sequence */
    OP* op_sibling;	/* children, e.g. arguments */
    OP* (CPERLscope(*op_ppaddr))(pTHX);	/* which pp function? */
    PADOFFSET op_targ;
    OPCODE op_type;	/* which op? */
    U16 op_seq;	/* assigned by optimizer */
    U8 op_flags;	/* flags for all ops */
    U8 op_private;	/* flags for ust this type of op */