How to get User full name or first name in confiform

[Dhiraj Kr_ Gupta]

I have a confiform field definition with field User. So i got user name as Snow, John2 [ABC] Or aa0000. I want only to return John in Display or confiform table view.

[Alex Medved _ConfiForms_]

user.fullName

See https://wiki.vertuna.com/display/CONFIFORMS/Accessing+field+values+and+properties

[Dhiraj Kr_ Gupta]

I want something different 

For eg

Full name : Medved, Alex23[CONF]

Output : Alex 

I am trying this in the formula but getting error Unknown operator at position 46

IF(EMPTY(SPLIT(REGEXREPLACE([entry.Name.fullName], "\[?\d+\]?", ""), ",")[1]), 

   SPLIT(REGEXREPLACE([entry.Name.fullName], "\[?\d+\]?", ""), ",")[0].strip(), 

   SPLIT(REGEXREPLACE([entry.Name.fullName], "\[?\d+\]?", ""), ",")[1].strip()

)

[Dhiraj Kr_ Gupta]

FirstName= [entry.Name.fullName.replaceAll('.*?\\,\\s(\\D+?)(\\d|\\s|\\[).*', '$1')].

FirstName=[entry.OwnerName.split(", ")[1].replaceAll('[\\d\\[\\]]', '').split(' ')[0]]

It is also not working after IFTTT macro