split function in calculated fields

When i try to save in Splunk Web calculated fields that contains split function i have a "Encountered the following error while trying to save: In handler 'props-eval': Bad function" message. Why i can't use this function in calculated fields? There is no word about this limitation here in Splunk Documentation, Examples of Eval expression that are not working:

split(anyfield,";")

or

split("x:x",":")

But in conjunction with eval in Search these are working fine.

Splunk Version............................................6.0 Splunk Build............................................182037