libarray-unique-perl | Tie-able array that allows only unique values | Mehr ...
Array::Unique lets you create an array which will allow only one occurrence of any value. In other words, no matter how many times you put in 42, it will keep only the first occurrence and the rest will be dropped. . Uniqueness is checked with the 'eq' operator so among other things it is case sensitive. As a side effect, the module does not allow undef as a value in the array.
