f@o(…)

f@o(…)

With different function options, a function can implement different functions. The basic format of function options is f@o(…), in which "o" is the option of function f

f

Function name

@o

Function option. Different options support different functions, and a same option has similar meaning in different functions

(...)

The input parameters of a function. The separator of parameters can be colon ":", comma ",", and semicolon ";" and their priorities decrease from left to right just as the order of introducing them