I have this code:
(setf prg '(+ 1 n)) ; define a very simple program
(print prg) ; print the program
I need to add more code so that when the above code is executed, it should set n to 1 and execute the program stored in variable prg.
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Prg is a list of 3 values, you need to evaluate it in an environment where n is bound to 0. You can bind n globally to 0 with defvar. Why not use a function instead?coredump– coredump2021-01-30 14:23:41 +00:00Commented Jan 30, 2021 at 14:23
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1 Answer
I think you want to do this:
(setf prg (lambda (n) + 1 n)) ; define a very simple program
(print (funcall prg 1)) ; print the program
In your example: (+ 1 n) is not a valid Common Lisp program.
EDIT: If you wanted to play with variables binding, you could also declare a variable:
(setf prg '(+ 1 n)) ; define a Common Lisp expression
(defparameter n 1) ; bind a variable to the value 1
(print (eval prg)) ; evaluate the Common Lisp expression
> 2
