Modern color-functions use a comma-free syntax because functions in CSS are used to group/name a syntax chunk. They should work by the same rules that CSS grammar does in general: values are optional ...
When making a method or function call, there MUST NOT be a space between the method or function name and the opening parenthesis.
Composite functions are made when the output from one function is used as the input of another function. The names of the functions are written next to each other, with the function that is used first ...