"DESCRIBE FUNCTION array" throws ParseException

hive> describe function array;
describe function array;
FAILED: Parse Error: line 1:18 cannot recognize input 'array' in describe statement

hive> describe function 'array';
describe function 'array';
OK
array(n0, n1...) - Creates an array with the given elements 
Time taken: 0.396 seconds
hive> describe function map;
describe function map;
FAILED: Parse Error: line 1:18 cannot recognize input 'map' in describe statement

hive> describe function 'map';
describe function 'map';
OK
map(key0, value0, key1, value1...) - Creates a map with the given key/value pairs 
Time taken: 0.054 seconds
hive> describe function case;
describe function case;
FAILED: Parse Error: line 1:18 cannot recognize input 'case' in describe statement

hive> describe function 'case';
describe function 'case';
OK
There is no documentation for function case
Time taken: 0.072 seconds