1{ 2 # pick-first-value data expression 3 # empty configs are not accepted by Kea 4 "Dhcp6": { 5 "valid-lifetime": 1800, 6 "client-classes": [ 7 # reduce literals 8 { 9 "name": "literal", 10 /// from: match if (option dhcp6.client-data) = (pick-first-value(substring('abcd', 0, 0), null, 'foobar')) 11 "test": "option[45].hex == 'foobar'" 12 }, 13 # null 14 { 15 "name": "null", 16 /// from: match if (option dhcp6.client-data) = (pick-first-value(null)) 17 "test": "option[45].hex == ''" 18 } 19 ] 20 } 21} 22