Tricky.

You can't get some characters into strings, so it wouldn't work in all cases. A common string delimiter in file data is Chr(0), and you can't get that into a string to supply as a parameter. You could pass just the numeric value I guess, but that would make passing multi-character delimitors difficult. To be useful you'd probably want to have multiple alternate values - space, tab, CR and LF are the most obvious selection.

If would be nice to be able to differentiate between CRLF and CR delimited files though.