define a common lisp macro named threewaybranch, which takes three parameters: x, y, and z. all parameters will be lists containing an arbitrary number of sublists where the first sublist is a conditional.

The common lisp macro is defined as:(set threewaybranch x y (+ z 3)) .What is lisp macro?The Common Lisp macro facility enables the user to describe arbitrary functions that convert different Lisp forms prior to actually evaluating or compiling them. This is completed at the expression level, rather than at the character-string level as is done in most other languages.Lisp macros have the unique ability to control evaluation (as demonstrated by evaluating the input expression via expr) and perform arbitrary source-to-source transformations with full power of the language at their disposal.The Lisp expression would be passed to the macro function during a macro expansion phase. At macro expansion time, this macro function can perform any computation. This call's output must be Lisp code once more. This Lisp code is then seen and executed by the interpreter or compiler.To learn more about lisp macro refer to :https://brainly.com/question/15855701#SPJ4