arrays in pl/pgsql - Mailing list pgsql-sql

Is it possible in pl/pgsql to declare and then assign to arrays?
For example if I declare an array as follows
DECLARE    dn text[];

How do I assign the first element to a string (say 'a').
I have tried the following (which doesn't work)
dn[1] := \'a\';

The parser doesn't like the [ that follows dn.