On 18th of February, Alvaro Herrera committed patch:
Convert Postgres arrays to Perl arrays on PL/perl input arguments More generally, arrays are turned in Perl array references, and row and composite types are turned into Perl hash references. This is done recursively, in a way that's natural to every Perl programmer. To avoid a backwards compatibility hit, the string representation of each structure is also available if the function requests it. Authors: Alexey Klyukin and Alex Hunsaker. Some code cleanups by me.