confused by int2vector typdelim

[jian he <jian.universality@xxxxxxxxx>]

hi.

select
        pt.typtype
        , pt.typcategory
        , pt.typdelim
        , pt.typelem  
        , pt1.typname   as elem_type
        ,pt.typsubscript
        ,pt.typname
from    pg_type pt  join pg_type pt1 on pt.typelem = pt1.oid
where   pt.typname = 'int2vector';

returns
 typtype | typcategory | typdelim | typelem | elem_type |      typsubscript       |  typname
---------+-------------+---------+----------+-----------+-------------------------+------------
 b        | A          | ,        |      21  | int2     | array_subscript_handler | int2vector
(1 row)

from manual:

typdelim char
Character that separates two values of this type when parsing array input. Note that the delimiter is associated with the array element data type, not the array data type.

 

should I expect the typdelim be a white space? Since '1 2'::int2vector works, '1,2'::int2vector does not work.