Certain aspects of this me of the modf macro for Common Lisp: https://github.com/smithzvk/modf https://github.com/smithzvk/modf You use place syntax like what

Certain aspects of this me of the modf macro for Common Lisp: https://github.com/smithzvk/modf https://github.com/smithzvk/modf You use place syntax like what is used with incf or setf, denoting part of some complex object. But the modification is made to the corresponding part of a copy of the object, and the entire new object is returned.