Hi. Need help with creating the ‘for’ macro. It must take a parameter, an initial value, an end value, and a loop step. Macro must return amount of iteration. Various operations should take place inside it. It should be designed without leaks.The preliminary version looks like this:
(defmacro for ((param-name start-value end-value &optional (step1 1)) &body body)
(let* ((func-name (gensym))
(start (gensym))
(param-name (gensym))
(comparison (if (< step1 0) '< '>))
(end (gensym))
(step (gensym))
(k (gensym)))
'(labels ((,func-name (,param-name ,start ,end ,step ,k)
(let ((new-exprs (progn ,))
(newK (+ 1 ,k)))
(if (,comparison ,end ,param-name)
(,func-name (+ ,param-name ,step) ,start ,end ,step newK)
newK))))
(,func-name ,param-name ,start-value ,end-value ,step1 0))))
I understand that it looks terrible. I don’t understand how you can access the parameter without violating the rule about leaks.
(defmacro for
((param-name start-value end-value &optional (step1 1)) &body body)
(let* ((func-name (gensym))
(comp (gensym))
(comparison (if (< step1 0) '<= '>=))
(start (gensym))
(end (gensym))
(step (gensym))
(k (gensym)))
`(let ((,start ,start-value)
(,comp ,comparison)
(,end ,end-value)
(,step ,step1))
(labels ((,func-name (,param-name ,k)
(if (,comparison ,end ,param-name)
(progn (progn ,@body)
(,func-name (+ ,param-name ,step)
(1+ ,k)) ,k))))
(,func-name ,start 1)))))
Do you know how can I close leak with comparison? When I am trying to bound comp to evaluated operator of comparison I receive error.