Entry number from string/label

[Calle]

Hi,

Datelabel gives date label/string from an entry number. How can I go the other way around and create an entry number from a string.

For example:

cal(d) 2020:01:29
display datelabel(1) *displays 2020:01:29
com dateString = "2020:01:29"
display someFunction(dateString) * should display 1

Thanks,
Carl