Functions are specialized commands used to manipulate strings and other input. The format for a function is of this form: [fun-name(<input>)] Although usually the 's indicate an input that is optional, in this case they are necessary and tell the MUX that this is a function, although nested functions (like [first(rest(This is a nice day))] returns 'is') do not require more than one pair of 's. Nested brackets may be used when it is necessary to insert a function call in the middle of an argument, like [get(me/[get(me/vz)])], which returns the contents of the attribute named in the VZ attribute.
For help on a particular function, type 'help <functionname>'. You may need to include the parentheses with the function name, ie. 'help <functionname>()'. Type 'help' or '@list functions' for a list of the available functions. 'help function classes' will show a list of the functions broken down into classes.