[Haskell-beginners] Parse string with optional entries [Parsec]

[Stefan.Lukasser-EE at infineon.com]

Hi all,

I'm trying to parse a string in one of the following forms using Parsec:

"1\t1\t123\t456" -> desired output: [Just 1, Just 1, Just 123, Just 456]

or

"1\t\1\t\t456"  -> desired output: [Just 1, Just 1, Nothing, Just 456]

i.e., the input is a list of numbers, separated by '\t' characters, with the possibility of missing entries.
I'm having troubles with the backtracking in case of missing numbers. Can anybody give me a hint?

Thanks in advance,
Stefan