org str 'my string'; addr: 'SCALAR(0x22e8af8)'
rs 1 str 'my string + my string add'; addr: 'SCALAR(0x22e8af8)'
rs 2 str 'my string + my string add + add to ref'; ref: 'SCALAR(0x22e8af8)'; addr: 'SCALAR(0x22e8af8)'