Iterate through a table type variable

Hi,

     I want to assign value by value into each of the table type probably through an index like varchar_tab(i):='abc'

basically my intention is to convert comma seperated values 1,2,3 as

1

2

3

This I'm planning to implement using a function which would accept a varchar and load it into a table type varchar variable.

Request to help.

Thanks in advance.

-Athrey