I pretty sure it should be shoter solution.(defun modulename-vinlist(val lst)  Check if value in list  (let ((res no))    (let (vv)      (dolist (pi lst vv)        (when (string-equal pi val)          (setq res yes)          (return))        (setq vv (cons pi vv))))    (when (string-equal res yes)      t)))
Checking if val is present in list
elisp
You want member:(member val lst)For example(if (member 3 '(1 2 3)) t nil) ; t(if (member 4 '(1 2 3)) t nil) ; nil