I've seen actions based on switch (12 options) statement to get the first three letters from a date variable.
I use a one-liner.
The
DATE-VARIABLE is an input date type and it returns the first three letters of a month (these are in portuguese).
Substr("JanFevMarAbrMaiJunJulAgoSetOutNovDez",(Month(DATE-VARIABLE)*3)-3,3)
Hope it is usefull to somebody.