start making file source configurable

utils.lisp

@@ -27,10 +27,19 @@
 (defun string->bool (s)
   (if (string-equal (string-downcase s) "true") t nil))
 
+(defun find-string (str seq)
+  (sequence:find str seq :test #'string-equal))
+
 (defclass data-source ()
   ((cache :initform nil :accessor cache)
    (file-path :initarg :file-path :accessor file-path)))
 
+(defun maybe-pass (func arg)
+  "Pass ARG to FUNC if arg is not nil."
+  (if (fnil)arg
+      (funcall func arg)
+      (funcall func)))
+
 (defmacro define-data-source (singular-name)
   (let* ((class-name (symbolicate singular-name '-data-source))
          (constructor-name (symbolicate 'make- singular-name '-data-source))
@@ -39,8 +48,8 @@
     `(progn
        (defclass ,class-name (data-source) ())
 
-       (defun ,constructor-name ()
-         (make-instance ',class-name :file-path ,file-name)))))
+       (defun ,constructor-name (&optional (file-path ,file-name))
+         (make-instance ',class-name :file-path file-path)))))
 
 (defgeneric data (data-source))
 (defmethod data ((ds data-source))