Add support for null literal in jsonian-path

jsonian-tests.el

@@ -174,6 +174,13 @@ We test that all lines are unchanged"
              '("fizz" 4 "some")))
     (should (= (point) (point-min)))))
 
+(ert-deftest jsonian-path-with-null ()
+  (with-file-and-point "path-with-null" (point-min)
+    (should (equal
+             (jsonian-path nil 19)
+             '("b")))
+    (should (= (point) (point-min)))))
+
 (ert-deftest jsonian-simple-segment ()
   "Check that we correctly identify simple segments."
   (mapc

jsonian.el

@@ -180,6 +180,8 @@ Otherwise it will parse back to the beginning of the file."
                (jsonian--backward-true))
               ;; Boolean literal: false
               ((eq (char-before) ?e) (jsonian--backward-false))
+              ;; null literal
+              ((eq (char-before) ?l) (jsonian--backward-null))
               ((bobp) (cl-return nil))
               (t  (user-error "`jsonian--path': Unexpected character '%s'" (if (bobp) "BOB" (format "%c" (char-before)))))))))
 
@@ -420,6 +422,7 @@ and ARG2."
 
 (jsonian--defun-traverse "true")
 (jsonian--defun-traverse "false")
+(jsonian--defun-traverse "null")
 
 (jsonian--defun-traverse whitespace (x)
   (or (= x ?\ )

test-assets/path-with-null.json

@@ -0,0 +1,4 @@
+{
+  "a": null,
+  "b": true
+}