Where is explained the Integration Center functions (operations) ?

[pboulicaut]

Integration Center comes with a set of operations : 

• Concatenate/Append

• To Upper Case

• To Lower Case

• Truncate

• Trim Whitespace

• Remove All

• Replace All

• Prepend Text

• Truncate from Left

• Truncate from Right

• Substring

• Split

However, there is no explanation for them in the documentation : 

Available Operations Based On Calculated Field Data Types | SAP Help Portal

I would like to split email address in 2 fields : 

user for the section before @

domain for the section after @

I'm unclear weather i should use split or substring